Download View/Open - ESIRC - Emporia State University

THE
ANALYSIS
OT
FOURTH
AND
DESIGN
~
GENERATION
LANGUAGE
A Thesis
Presented to the
Division of Mathematics and Physical Sciences
EMPORIA STATE UNIVERSITY
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
by
Karen I. Craft
May 1988
AN
ABSTRACT
OF
THE
THESIS
OF
Karen I. Craft for the Master of Science Degree
in Mathematics presented on March 1988
The Analysis and Design of a
Fourth Generation Language
The
enclosed
thesis
contains
a
study
of
the
first
three phases of the software engineering process as applied
to
the
project
(4GL).
of
Initially,
creating a
fourth
the
defined.
4GL
users are also defined the 4GL,
is
generation
Three
language
levels
the software engineer who creates
the application developer who uses the language to
develop a
specific application program, and the final
end­
user who operates the application program created with
4GL.
Incl uded
flow of
of
are
schematic
the language.
diagrams
to
show
the
the
logic
Sample screens are also included to
show the results of using the language for an application.
The
fourth
generation
process wi th
modul es
screen handling,
handling,
printer
data
control,
language automates
to
handl e
menu
the code writing
systems,
data
entry,
keyboard handling, validity testing, error
access
and
fi le and
searches,
index
report
management,
generation,
and
internal
data management of buffers, pointers, and system functions.
463000
DP OCT 21 'e~
o.Jdd",
--===
I -
CONTENTS
Introduction
II - Analysis
III - Design
IV
v
===-­
1
18
18
Screen Design
29
Developer Interface
41
VI - Code Design
48
VII - The Library
57
VIII - Testing
66
IX - Summary
68
Bibliography
78
--===
TABLE
OT
FIGURE 1 - Main Menu Screen
FIGURE 2 -
FIGURES
===-­
• • . . • . • . . . . . • . 30
I/O Screen Format • . . • • • . . • • • • • • 32
FIGURE 3 - Sample Entry Screen • • • . • • • • . • • . • 33
FIGURE 4 - Sample Coding Menu Screen • • • . . . • • . . 34
FIGURE 5 - Sample Code Screen
• • . • • . • • . . . . • 35
FIGURE 6 - Application Specific Help Screen
• • • • • • 36
FIGURE 7 - 4GL General Use Help Screen • . . • . • • . . 36
FIGURE 8 - Data Search Menu Screen • .
.
• • . • .
• • • 37
FIGURE 9 - Sample Data Search Screen • • . • • • . . . • 38
FIGURE 10- Sample Report Menu Screen • • • • • • • • • • 39
FIGURE 11- Sample Report Format
• • • • . • • • • . • . 40
FIGURE 12- Sample Report Format
• • • • • • • • • • . • 46
FIGURE 13- System Structure Diagram
• • • • . . . • . . 51
FIGURE 14- System Structure Diagram (continued)
• • • • 52
FIGURE 15- System Structure Diagram (continued)
• • . . 53
I
---===
Overview
first
three
process
fourth
as
---
This
critical
it
===-­
INTRODUCTION
is
document
phases
app 1 i ed
generation
of
to
language.
contains
the
the
a
study
software
proj ec t
Ini tiall y,
the
engineering
of
it
of
crea t i ng
a
is necessary to
provide some background information which defines the terms
engineer i ng,
so-f tl4lt3re
Engineering),
and
Understanding these
( Comp u t er
CASE
4~
(Fourth
terms will
Aided
Generation
Sof tware
Language).
aid in better understanding
the goals of the project.
Background
the
Information --- Within the past few years,
ever-changi ng
presen ted
many
value-added
new
mi cro-compu ter
probl ems
computer
to
retailers
sof tware
market
sol ve.
In
the
wor 1 d
(VARS) ,
specific
has
of
Rtarget
markets R have become the emphasis, such as medical, dental,
retai 1 er
inventory, accounts receivabl e,
applications, to name a few.
general
for
sof tware
these
becomes
market
develop
these
more
a
needs,
necessity.
eff i c i en t
1 edger
Off-the-shelf software is too
spec ia 1 i zed
the
or general
fields,
Wi th
software
methods
to
the
therefore
recent
custom
flood
of
engineer
is
forced
to
produce
the
vol ume
of
I
applications
(Automated
designer
the
Software
competitive
-
We
to
writing
to
and
appl ication
Custom
H
their
way
keeps
Inc.)
ASCI I
and
the
for
had
to
in
find
a
to do custom software.
that
and
versatility.
another
·We
automated
programmers
applications
retain
to
-
at
the changes required
ASCII.
package
productivi ty
increase
st i l l
1
a
1eader
International,
at
and affordable
develop
team
describes
approach
process.
standardize
Adams,
Concepts
GhostWri ter,
programming
decided
Tom
needed.
of
2
Q..9.
Introduction
coding
find
the
code
necessary
it
efficiency,
to
maintenance
efficiency
Continuity
from
the maintenance and
one
training
effort to a minimum.
Software Engineering --­
Software engineering is not just a matter of
wr i t i ng code!
•••
The sof tware engi neer i ng li-Fe
cycle involves a more or less standard sequence
of phases.
At the outset of a software project,
a
set of requirements are gathered, describing
the objectives that the software must satisfy.
Next is an analysis of the requirements, exposing
important
patterns and structures.
These are
called the design specifications.
At
th i s
poi nt,
sof tware
desi gn
begi ns.
Usually
a
schematic
design
phase
precedes
detailed design.
Upon completion of design, code
is wri tten --- this is the implementation phase -­
- followed by testing and l11dintenance.
I -
I~duction
2.9
---
Sof tware engi neer i ng therefore i nvol ves
3
the foll owi ng
phases in the life cycle --­
1
2
3
4
5
6
-
Requirements Analysis
Design
ImplementationTesting
Maintenance
-
gathering the objectives
exposing patterns and structures
schematic and then detailed design
actual coding
verifying correctness
correcting, updating, revising
Advances
in
technology and
techniques to
improve the process have not kept up wi th the
demand for new software; or perhaps programmers
have been too busy to 1earn them.
Whatever the
cause, many programmers have apparently decided
to skip designing software in favor of just
getting the job done.
R I t
can always be fixed
later R seems to be the attitude of the day.
Programming is costl y enough when it is done
correctly.
this haphazard rush to completion
only adds to the costs, both in maintaining the
software
a~
in
producing
truly
useful
applications.
In
a
software
engineering
project,
the
greatest effort is expended in the later phases
of
the
life
cycle.
Coding,
testing,
and
maintenance take far more time than analysis and
schematic design.
In contrast, decisions made early in the life
cycle have the greatest impact on the quality and
maintainability
of
the
resulting
software.
Studies have shown, for example,
that errors
detected during [the] requirements [phase] are
correc ted in far 1ess time than errors detec ted
during implementation or maintenance.
I n other words, the 1east effor t i s i nvesied
in the most important phases of the life cycle!
2.9.
I - Introduction ---
CASE
---
A
CASE
produc t i s
any
compu ter
tool
assists any phase of the software engineering process.
defini tion
is qui te
1 iberal
due
to
the fact
4
that
The
that software
-Any computer tool
engineering itself is a broad activity.
that assists in the process can legitimately claim the CASE
label. ,,2
MCASE
generation,
tools
can
generation
ization
partially
products.
and
documentation,
cr it i ca 1
design.­
phases
resulting
of
automate
Few,
design,
if
an y ,
do all
the
coding and
testing
will
better
in
lower
also
and
promote
more
maintenance
standard­
accessible
costs.
In
in principle, redirect resources to the
requ i remen ts,
anal ysi s,
and
schema tic
2
Through extensive user surveys (published in
So-ftAlt3re Engineering:
CAS£),
BTR
[Business Technology Research of Wellesley Hills,
MAl
determined
that
most
users
have
been
emp 1 oyi ng CASE tool s for on 1 y the past 18 to 24
months.
[as of March 1988l
CASE tools break down into two segments:
design automation and programming.
Programming
tool s are primari 1 y avai labl e on IBM mainframes
at prices in excess of $100,OOO, according to
Bayer [David Bayer, an industry analyst with
Montgomery Securities, San Francisco, CAl. The
CanputerAided
code
of application builders and code
CASE
support
this way CASE will,
and
3
"This is the goal
phases.
analysis
testing and maintenance.
these things, however.CASE
perform
.e.g
I - Introduction ---
5
trend, however, is to less expensive products
that
can
run
on
micro
and
minicomputer
workstation
platforms.
He
expects
more
sophisticate2 programming tools to appear this
year [1988].
The proj ec t inc 1uded herei n is fo11 owi ng the trend toward
the micro market.
The
CASE
technologies.
ana 1ysi sand
inc1 ude
around
Front-end
desi gn
ai ds.
app1 ication
the
or
upper-cd-se
B.3ck-end
or
lower
or
case
distinct
include
tools
lower
Cd-se
p r oj ec t
Th i s
generators.
back-end
two
includes
definition
tools
which
the
tools
centers
are also
labeled 4GLs or Fourth Generation Languages.
4GLs
-These
application
generators
assist
the
later phases of the [software engineering] life cycle, from
detai 1ed
They
design
focus
through
on
coding,
process,
testing,
format,
and maintenance.
and
documen ta t i on
disciplines, not information or project management.­
A 4GL
is ac tua 11 y a
thought of as a
the paren t
of
type of CASE,
2
bu t i s more easi 1y
subset of the CASE technology, and also as
the CASE.
In
its broadest sense,
it
is the
the back-end or lower CASE tool mentioned above.
As
a
languages
response
(4GLs)
to
are
many
new
becoming
needs,
more
four th
prevalent
genera t i on
and
are
quickly replacing third generation languages (3GLs) such as
I
Introduction ---
-
BASIC,
PASCAL,
application
tel I
the
Using a
what
COBOL,
4GL,
to
This
is
collection
abou t
of
90%
all
applications.
as
management,
record,
standardized
tasks
are
next.
A
that
higher
programs
in
handl ed
4GL
the
these
does
the
the
operating
level.
interface
between
the
tell
fact
managemen t
menial
tasks
"macros·
and
no
longer
the 4GL program
and
same
from
code
needed
operating
is a
all
a
is
f or
the
users
need,
screen
1evel
for
programmer,
The
re-i nven t
4GL
become
or
common
application
hardware,
the
then
app 1 i ca t i on
system
fi Ie,
tasks.
standard
one
for
II
to
the
programs
onl y
at
standardizes
operator
and
operator
and
the
appl ication.
a
the
hardware
devices, and the 4GL standardizes the interface between
programmer,
all
collection
higher
to
an
contains
manipulation,
all
thing
does
4GL
management
wi th
tasks
same
a
which
needs
to
task.
that automate data,
report
developed
each
code
contains
the
language
of
that
that
character
4GL
system
The
the
requ i res
the
operating system
the
programmer
All
3GL
detai 1
pre-written
management,
screen,
every
need only
to
s tan dar d
of management
fiel d,
II
of
etc.,
app 1 i ca t i on
wheel.
due
1ow-I evel
device
collection
do
Just as an
standard
such
to
the programmer
do.
A
etc.
to specifically use
how
organized
of
FORTRAN,
programmer
compu ter
6
Q.9
A
the
truel y
--- £9
I - Introduction ---
efficient
4GL
will
automate
possi bl e.
tasks as
programmer
All
as
that
many
standard
left
for
is
or
7
normal
the appl ication
to do is to add the non-standard tasks specific
to the application.
4GLs
ev 0 1uti on
been
have
of
al so
been
languages H4 ,
designed to do a
to do a
descr ibed
Ha
as
Ha
con t i nued
specialized language that has
specific function H4 , as being Hable
task with roughly one-tenth of the code needed in a
3GL. 4 •
HWi th
H
automated.
4GLs,
the
prec i se
ins truc t ions
The language has been demystified.
a dialogue between user and computer,
the user's probl em.
have
been
4GLs employ
interacting to solve
The focus is on
the task,
not on
the
5
computer. H
Many
allow an
1 evel s
of
end-user
system-house
4GLS
4GLs
ex i st,
to create a
by
used
from
simp 1 er
4GLs
wh i ch
simpl e database to powerful
software
The
engineers.
difference between the two is the degree of flexibility and
of
the
de ta i 1 allowed
i nit s
use.
The simpl e
4GLs allow
for only very basic, standard functions, while the powerful
4GLs
allow
nonstandard
the
versa ti 1 i ty
func t ions when
and the extended DmacroH
of
adding
needed usi ng
language of
the
the host
unusua 1 ,
1anguage
the 4GL itself.
This
study considers the later, the powerful system-house 4GL.
--- 2.9
I - Introduction ---
ASCII,
product
the
as
system, 4
generator,
and
Engineering)
(4)
a
GhostWriter,
an
program
(2)
Aided
echoes
the 4GL as an
an
Software
development.
herein
their
development
ap p I i ca t i on
(Computer
contained
consi ders
define
code writing process,
CASE
for
approach
def i nit ions and
Pascal
(3)
product
engineering
of
an automated
(1)
application
producers
8
5
The
these
ex tensi on
four
of
the
language with the creation of 8macro 8 procedures and
functions
system-house
for
use
create
to
rela ti onal
database management applications.
In
Summary
study
of
summary,
the first
this
three cri tical
document
phases of
engineering process (the requirements,
phases)
for
involves
a
appl ication
lower CASE).
generator
four th
subset
generat i on
of
generator
the
technology
the software
analysis and design
language.
CASE
the
Br i ef I y,
technology
(al so call ed
called
th i s
the
back-end or
It can also be described as an automatic code
wi th
definitions,
functional
a
contains
screen/report
creat i on,
data base management, procedural
integration
as
described
in
dictionary
language, and
8The
James Martin
Productivity Series 82
The
creation
of
a
fourth
generation
language
(4GL)
I -
~
Introduction ---
itself requires quite an involved programming project.
ASCII
9
The
programming team spent three-and-a-half years work on
their GhostWriter written in Turbo Pascal.
1
This document
analyzes the type of product produced by this company.
--===
I
A high-level
d i r- ec t i on s •
The
===-­
ANALYSIS
I
analysis at
fir-st
step
this point
is
involves sever-al
to define
the user-s,
and
their- r-espective needs.
The
User- --- Defining the needs or- r-equir-ements of a
softwar-e
user-.
pr-oject
In
or-der-
also
initially
r-equir-es
to avoi d any confusi on,
defining
thr-ee
the
ter-ms ar-e
used consistently within this document --­
(1) The softwar-e enQineer- who cr-eates the 4GL.
(2) The application developer- who uses the 4GL.
(3) The client/end-user- or- oper-ator- who uses
the application cr-eated with the 4GL.
In this situation, the application developer- (also known as
a system developer-)
using
the 4GL,
var-iety of
4GL
be
is the user- of the 4GL, however-, while
this developer- pr-oduces appl ications for- a
clients or-
wr- it ten
in
end-user-s.
such
di ffer-en t
var- ia t ions
in
analyzing
the
of
needs
a
manner-
This
as
r-equir-es
to
a
11 ow
database app 1 i ca t ions.
the
application
that
for-
the
many
Ther-efor-e
developer-,
also
involves analyzing the needs of as many client applications
as possible.
The application developer- becomes the Dmiddle­
manU for- the client, the final application end-user-.
two
1 evel s
of
ana 1 ysi s
ar-e consi der-ed,
Thus,
the needs of
the
II - Anal.l.sis
application
2.9
and
develope~
the
needs
of
the
11
develope~~s
clients.
James
analysis
-
Hughes
p~ocess
consisting of
explains
--- "At
a
standa~d
p~oject
app~oach
initiation, a
systems analysts and
time to the team - must define the
use~s
to
p~oject
the
team
assigned full
p~elimina~y
requirements
of the system."
"Traditionally, at
dozens
of
users
produces a
to
this point analysts would interview
determine
requirements.
This
often
long list of wants and needs that are difficult
to analyze and use for system development."
"A
users
better
approach
the
definition
in
is
of
to
involve a
preliminary
few
experienced
requirements and
major system externals - such as menus, data-entry
on-line query displays and reports.
sc~eens,
These system externals
should then be incorporated into a horizontal prototype."
·Users
horizontal
can
rank
the
functions
in
the
8
Software
En9inee~
software engineer
developer
and
prototype to determine which functions should be
au tomated."
The
review
(use~
of
and Application Developer Needs --­
(the 4GL developer)
the 4GL)
and appl ication
have much in common.
They are
II
.e.g
Anal l::,si s
both
developers
creates general
for
a
cl ient.
applications for
The
software
12
engineer
the application developer,
and the application developer creates specific applications
for
the client/end-user.
several
quality
ivi ty,
code
As mentioned in the introduction,
requirements
efficiency,
ized appl ications,
include
maintenance
increased
product­
efficiency,
and versati 1 i ty.
Further
standard­
clarification
is now needed.
Increased
application
in
productivity
involves
the
production
of an
less time than with previous methods.
This
is easily measureable by keeping time logs on all projects,
however,
one
must
remember
that
not
all
projects
are
created equal.
Maintenance
needs,
most
correcting errors,
organizations,
programming
Wi th
38%
includes updating
is
it
4GLs 78% of
and adding new capabi 1 i ties.
is
dedicated
the system for changing
estimated
to maintaining
the time is spen t
on mai n tenance. 4
A rat i 0
that
78%
existing
of
In
the
systems.
on or i gi na 1 codi ng and
of 88% -
28%
is the mi n imum
acceptable goal of this project with the ultimate goal of a
95%
-
5%
provide
ra t i o.
The appl ication
parameters
to
the
4GL
developer
to
define
is required to
the
data
file
II - Anal~sis ---
structure,
words,
2.9
entry
screens,
the majority of
and
report
formats.
other
the time for using the 4GL is spent
in designing the appl ication database,
any application,
In
13
however,
as
is necessary
little additional
in
time is needed
beyond that stage.
Efficiency
speed,
memory,
eFficiency can
developer
overlays
and
major
measured
consider
data
of
efficient
wi th
disk
areas
timing
access
files.
ex terna 1 code
to
Speed
code.
tests.
time
The
when
Both
the app 1 i ca t i on developer
concern
the
up
using
software
have access
speed
4GL
to
the
processi ng.
efFiciency can also be implemented using inline and
proj ec t
can
three
maintenance
managing
external code.
keep
be
in 1 i ne and
of
H~ory
and
must
engi neer and
use
involves
inc 1ude use of PC/XT equ i pmen t,
the
code as
compare
another
the
in
~intenance
order
It
all
application
compact
memory
to
as possible.
required
determine
by
the
it
is necessary to
The 4GL developer
one
algorithm
memory
over
efficiency.
eFFiciency is included here as the top priority
requirement.
However ,
Due to the fact that the constraints of the
is
desi gn
developer
not
for
must
a
truely
the
have
measurable
software
an
feature.
engineer
under 1yi ng
purpose
and
of
II -
being easily updateable as new needs surface.
a
Y
gray
area-.
An
time-
and
efficient
elaborate
upon
upon
the
algorithm
memory-wise,
maintain because of a
based
14
2..9.
­
Anal~sis
but
may
too
lack of readability.
opinion
their expertise.
of
the
This becomes
be
quite
difficult
to
Readability is
programmers
and
dependant
Readability and maintenance have top
priority over speed and memory.
Standardi zing
ways.
app 1 i ca t ions
much
to
point
the 4GL.
be
concerned
input,
keyboard
handling;
color
prevent
development
developer's
usi ng
two maj or
From the programming and maintenance point of view,
standardized al gori thms
save
is impor tan t i n
time.
view,
From
this
is
wi th
how
handling,
and
and
the
app 1 i ca t i on
appl ication
no
longer
handl es
testing,
needs
menus;
and
control;
screen
search
routines;
windowing;
and
the major purpose fo ....
validity
printer
the wheel
the
The app 1 i ca t i on developer
output
coding,
of
reinventing
error
functions,
buffers;
pointers; system functions; or even the processing of data,
i ndi ces
and
control
of
concerned
f i 1e
the
wi th
managemen t •
4GL.
whtilt
The
the
These
application
system
must
application and not how it does it.
are
tota 11 y i n
developer
do
for
the
then
the
is
special
II - Ana 1~s i s
.2.9. 15
Versatility
measured
wi th
application
is
a
time.
quality
to
Due
requirements
that
the
of
can
vast
really
range
of
only
specific
client/end-users,
it
impossible
to foresee and allow for all
that might
be needed by the appl ication developer.
the
major
design
requirements
to allow for
are
be
is
possible features
defined,
a
further
requirement
is
code wi thin
the program to add the non-standard features.
Standard code is code that
direct appl ication
After
is protected and not allowed to
be changed by the application programmer.
of versatility is provided for with
to
the
application
procedures
in
requirements
are
Standard Pascal
4GL macros
to
the
developer
any
coded
<described
The
that
the
programmer
designed
code
to
contain
stubbed
specific
application
application
programmer.
extended
in more detai 1
standard
are
by
The requirement
code files accessible
unforeseen
commands and an
application
added.
developer
which
programmer
as
files
handl e
language set
later)
the
89
are avai lable
specific
created
-
of
code
is
by
the
4GL
99"/.
of
all
application needs.
These include automatic handling of the
functions
in
listed
paragraph above.
the
Additional
·Standardizing
Appl ications·
code added by the application
developer is typically 1-5% of the total.
II - Analysis ---
Client/End-User
user
is a
design
is directed
entire
Needs --- Quite often
novice wi th
As mentioned
to
to computer
the needs of
earlier,
the client/end­
operation.
the new computer
requires
the operator
same
a
required
from
In more specific
stdnddrd screen
that all
format
the
throughou t
terms,
Id)'oUt
prompts will
the
operator
are avai lable at all
level
with
descriptions.
required
record
or
data
All
in
en tire
for
second
searches.
numbering,
attributes,
in
the
phase
Report
checked
are
order
program
file.
of
first
concurren t
for
OR,
for
and
totals,
the
saving
any
the
the database allow for
phase
NOT,
and
in
field
f.I<3lidit.v and
before
search
Forl11dts allow for
column
assure
opera t i on.
limitations on any or all
The
allows
to
Help screens
limitations,
tested
S~rches
to be
input is prompted at
is
for any
searches of
Ddtd
data
fields
is
be consistently seen
type,
data
coded
searches
available
the
times.
to the database.
mul tiple
allows
user.
this first of
Color coding aids in prompting the user also.
field
All
maintenance is the top priorty of the
Every move
thoroughly prompted.
the
respect
16
project, but consistent user-interface is the second
priority.
all
Po
---
of
col umnar
and
can
however
wi 1d
card
formats,
page
counters.
such as bold and underline,
development
cr iter ia,
XOR,
fields
Printer
be embedded in
II - Analysis ---
report formats.
Summary
--- P9 17
User-entered subtitles are also allowed.
In
summar y ,
the
fun c t i on s
t ha t
automated include
1 - a menu system,
2 - data-entry/display screen functions
(I/O screens),
color coding
windowing
3 - data entry,
keyboard handling
validity testing
error handl i ng
4 - data access (searches),
5 - report generation (output)
printer control
6 - file management
indices
saving, deleting, reading data file
7 - internal data management
buffers
pointers
system functions
processing of data
wi 1 1
be
I I I
--===
The
top
interface.
1evel
The
design
lower
1evel
DESIGN
===-­
concen tra tes
upon
of
design
the mechanics and maintenance aspects.
discuss the top
level
the
user­
concentrates upon
This chapter will
designing phase in terms of general
requirements and of the functions to be automated.
Phased
Development
is designed for
Turbo Pascal
second
--- Development of
two major
phases.
this project
The first
phase uses
3.x BCD with the top priority features.
phase
uses
Turbo
Pascal
4
and
adds
The
the
more
detailed features described in the following.
System
Requirements
---
Design
begins
project
declaration
of
the
constraints.
This
impl emented
on
IBM
PC/XT/ATs
compatibl es
preferrable)
hard drive
with
DOS 3.1
or
is
to
the
be
(XT/ATs are
or higher and 328K of RAM.
is recommended and mono,
are supported.
with
A
CGA, or EGA monitors
The application developer
is required to
use Turbo Pascal 3.x in the first phase of development and
as soon as version 4 is shipped, the second phase will use
it as its base.
III -
Design
IUl 19
Initialization
call
to execute
---
A
specifications.
within
separate
of
includes an
the
ini tial ization
even
screen,
from
desi gned
for
by
to keep
Once
program
immediate
the
created
from
A
sets of
loaded,
update of
Exit
point.
the
with
the program where
the operator
the date.
this
in
the drive and subdirectory
appl ication
option
of
to
subdirectories.
the
4GL
possible
ie.
This allows
ini tial ization
passed
the program declares
the data files are located,
files
parameter
by
the
the
f i les and
the program is
personalized
logo
developer,
then
appl ication
appears to declare the program name and any copyrights and
dates needed.
Pressing a key continues into the main menu
screen.
Menus
created
by
The main
the
applications.
4GL
menu
includes a
for
1 ist
the
entire appl ication
of
installed database
For example, a simple menu may include --­
e
= Codes
1
Chart of Accounts
2
T~ansactions
3 = Audi t Trai 1
Each
menu
1ayou t
is
sel ected
descr i bed
sel ec ted,
the
=
=
resul ts
in
more
in
the use of
detai 1
appropr ia te
1a ter.
f i 1es
are
the
same screen
When a menu
opened,
the
i tern
I/O
2.9. 20
III - Design
screen
is created, and the file and field definitions are
initialized.
Command
commandline
Line
appears
forms are used.
Once
at
the
within
bottom
a
menu
of
the
selection,
screen.
a
Two
The first allows adding and updating of
records and the second allows only reading of data --MenUj Add/Updatej Find/Data/CINtj RtpOl'tj PgUpj PgOn ---)
"enuj Find/Data/CINtj Reportj PgUpj PgDn ---)
Phase 2 includes security password options which allow for
read/wri te
access
or
read
only
access,
therefore
determining which commandline the end-user will see.
I/O
through a
Screens --- Data entry and display (for browsing
search buffer)
screens are
the same.
Standard
I/O screens contain the following:
1 - the menu title
2 - the current mode of operation
3 - a message area for errors and how to exit
4 - a data entry area
5 - a comrnandline area
6 - a field-level prompt area
7 - an input prompt for data entry limitations
8 - a status line including --- the number
records in the curren t f i 1 es, the number of
records
in
the search buffer,
the record
number of the record curren t 1 y bei ng en tered
or viewed.
2.9 21
II I - Desi 9n ---
Help
available
inc 1ude
aids,
Screens
by
---
pressing
the
user-spec i f i c
and
circular
a
user
list
as
Help
F1
screens
key.
the
such
displayed
space
bar
constantly
Phase 1 help
i nforma t i on,
manual
are
as
screens
accoun t i ng
sequentially
is
pressed.
in
a
Phase
2
screens allow for going to specific pages in the on-screen
manual,
for scrolling forward and backward sequentially as
desired,
and
allows
standard user manual
for
context-sensitive
help.
The
is pre-installed, however this manual
is accessible to the application developer for editing.
Data
Entry is standardized with
by the application developer.
these
screens
and
also
All
I/O screens defined
data is entered within
displayed
within
them
when
in
browse mode to page through a set of records in a search.
Data entry is also dependant upon file definitions defined
by the application developer using parameter tables.
sizes,
access
codes,
indexing, and field definitions are
contained in these tables.
field
definition
to
Data entry in a field uses the
determine
data
type,
validity tests, and its location within
field
has
field-level
File
length,
the record.
prompts displayed as
entered by the operator.
field
the
Each
field
is
II I - Desi gn ---
--- e.g 22
Phase 1 includes data types of string,
real,
byte,
f i el ds
date,
and
Automatic
keys
pressed.
data
fields
·Coding
A
as
only
minimum
A key click option is available for
lookup
fac i 1 i ty
explained
System·.
field level.
in
Validity
is
the
tests
bu i 1 t-i n
next
are
preinstalled codes.
and
tested
maximum
for
limits.
val id
usi ng the FlO key,
of
required
for
coded
section
on
the
performed
at
the
Coded fields are allowed which require entry
Numeric
data
is
String
data
entry
allowed beyond its maximum length limit.
also
sequential
(such as sequen t ia 1 i nvoi ce number i ng) and defau 1 t
fields are supported.
of
character.
integer, BCD
fields.
dates.
When an
the
record
is
for
not
Date entries are
entry
the record is tested for
If
tested
is executed
the ex i stence
is acceptible
it
is
recorded and any updates to related files are also updated
at
that
time,
such as updates to chart of account
totals
when a transaction is entered.
Phase 2 adds data
codes,
(mm/dd).
social
security
types for
numbers,
telephone numbers,
time,
and
short
zip
dates
II I
-
Design
2.9 23
Coding
efficient
for all
is
System --­ Due to the fact
to
use
codes
applications
reserved
for
t ~ \"
available
codes
program.
All
reference
data
~
i ,'"
!,
library
for
that
field.
time
a
;.
;
code
saved
such
codes
during
their
circular
returns
to
allowed
used
to
entry
of
throughout
test
the
I ist
the
a
to
be
as
are
all
standard
Menu 8
allows
the
A
codes
for
·CK'
for
check
entry
the
data
paging
entry
code
deleted
to
whence
flagged
guarantee
referenced by the coded field later.
the
be
source
or
documents
'IN'
for
an
or
updating)
by
lists the installed
through.
is
of
be accepted
order and
The
he
operator
came.
reference in a coded data field
the
program
codes must
in alphabetical
from
entire
quickly accessible
<adding
pop-on window
the
No duplicates are
indexed and
data
for
file,
a
va I i di ty
be
descriptions
is used as a
to
data
the coded data fields.
the F2 key.
codes and
I'"~
selection
Therefore,
example would
These
pressing
menu
the
code
transaction,
any
in
th i s
An
invoice.
at
fiel ds,
the coding library before they will
allowed.
a
This
fiel ds
entry
data
built-in coding system.
coded
entered in
in
some
coding library which contains lists of
used
as valid data in
(".
is a
Codes.
initialization of a
)i;
for
that i t is storage
in
then
Once
a
that
is
and
will
not
be
that
it
can
be
Design ---
Data
numbered
wi th
op t ion
Searches
1 ist
the
of
logical
AND
searches
search
type
data
fields
them.
a
~a ~
Numer i c
Searches
imp 1 emen ted
involving
usi ng
an
for
such
cri teria.
for
locate
string
as
two
data
to an
all
searches
the
(a
fields,
the beginning of
allow
minimum and maximum limits on the
fiel ds
allow
user-input
fields
the
proper
beginning
search
the
involved
criteria
searches
a
has
search
and
-Within-
'm'.
date
the
the special
a
the
special
i ndependen t
for
includes
end-user
of
selecting
contain
and
The
is matched from
to
which
records
the
numbers
user-input
I tallows
wit h
in
-Begin-End B
between
fiel d.
beg inn i n g
case
Data
menu
concurrent
After
options.
ending string.
data
all
to request
are
search
selection.
is prompted for
Str i ng
matching and
data
fields
or
an~
search).
the end-user
A
the
menu
se 1 ec t
he wishes
---
all
curren t
to
which
--- pg 24
the
names
locate all
string
user
wi thin
to
input
search.
indexed
field
B-tree index i ng and other
will
be
searches wi 11
be sequentially implemented.
Data search records are saved
in
called
a
circular
linked
list
a
search
buffer.
search buffer can be used for browsing through
the
screen
print
out
(pagi ng
numerous
to
the prev i ous or
reports.
Once
nex t
the
The
the data on
record)
search
has
or
to
been
II I
-
Desi gn
used,
2.9. 25
the search buffer can be cleared.
To
current
see
what
search
search buffer,
at
the commandline.
of
cr iter ia
con tai ned
used
in
have
been
used for
the operator can enter
A pop-on window will
for
the
cri teria
the
curren t
search.
search
The
'D'
for data
display the list
coun t
wi 11
buffer
the
of
records
di sp 1ayed
be
at the bottom of the screen.
Phase
wi 1 dcard
2 will
add
the OR,
searches,
and
al so
descending
fields.
sorts
according
XOR,
wi 11
to
NOT,
allow
any
IF-THEN-ELSE and
for
chosen
Search and replace features will
phase.
ascending
or
combination
of
be added in this
An operator option is available to search for case­
sensitive data.
Ad hoc searches are allowed in
this phase
and commonly used searches are saved as standard -macros·.
Data
the
Reports
application
imp 1 emen ted
field
usi ng
locations
options,
such
wi 11
imbedded
be
Report
developer.
tex t
f i 1 es.
and
field
as bold,
repor t,
the
if
exists.
none
---
A
is
In
phase
the
numbers.
1,
initialized by
these
will
list
Special
be
inc 1 ude
printer
and compressed print,
formats.
requested
numbered
are
These forma ts wi 11
underlining,
wi th i n
end-user
formats
to
of
When
request i ng
in i t ia 1 i ze a
a
search
installed reports
is
III - Design
29 26
displayed in menu fashion.
desired
report,
he
may
When
opt
the operator selects the
to
have
the
report
format
displayed before continuing.
This allows the operator
be
report.
sure
col umn
he
has
total s
example)
created
and
are
by
control
the
proper
numeric
available
the
grouping
directly
application
breaks,
other
Counters,
developer.
than
set
in
the
au toma. t i ca 11 y
repor t
manages
title block at
the
top
numeric
is
pagi na t i on
and
the
report.
formats
implement
the
The page length
and
each
for
grouping,
format
of
the
To
application developer adds specific code.
is
paging,
(by groups of 5,
through
to
the
key
crea t i on
One
line
that
of
in
a
the
report is required to contain fields from one common file.
Phase 2 allows for a more
which
fields
different
data
on
the
same
fi 1es.
Phase
H
free form"
line
2
can
uses
be
the
type repor tin
contained
4GL
i tsel f
in
to
create the report formats and parameters and also allows a
max imum
wi dth
repor t
formula or a special
of
132
charac ters.
A mat hema. t i ca 1
logic procedure can be manually coded
by the application developer.
Design
2.9 27
Pr inter
Suppor t
--- Due
the fac t
market,
each printer requires its own set of driver codes
compressed,
wide.
attributes,
6
or
Printers
8
such
1 ines
are
many
there is
standardization
special
the
that
little
for
for
to
per
as
inch,
supported
containing these code numbers.
printers
bold,
a
the
underline,
ital ics,
by
on
and double
parameter
file
The file is created by the
application developer and allows him to install
codes for
for any or all printer interfaces for which he has codes.
F i 1e
Managemen t
---
F i 1e
managemen t
implemented with a B-tree and indexing system.
wi 11
be
suppl ied
by
the appl ication
files and their respective fields.
is
not
another
files
and
allowed,
can
be
however,
made.
A
a
index
renaming
process
defini tions
the
has
01 d
been
indices
to
verified.
from
one
uti 1 i ty
define
file
to
re-indexes
It uses the file, field,
restructure
have as a
The
to
Restructuring of files
re-indexing
to
be
Parameters
developer
transfer
that have been corrupted.
loll ill
indices
backup
operator
then
after
unti 1
the
has
the
option to delete the old indices.
User
Interface --- User interface is well-served by
II I - Design
the
2.9. 28
several
standardized
manual
requirements
screens,
a
previousl y
pop-on
code
mentioned
window,
a
pop-on
or help window, and constant prompting at the field
1evel •
The
user wi 11
know that
he
is expec ted
to en ter
data when the color yellow (or reverse video on monochrome
monitors)
appears
will
prompted
be
on
the
by
screen.
listing
Even
all
character
possible
input
characters
allowed in the input.
Error messages must be preceded by
a
user
beep
to
si gna 1
message area.
the
At all
times,
explaining how to exit
keys will
Standard
these
application
constants.
look
ina
pre-determi ned
the user will
have a message
the current situation.
The use of
be consistent throughout the application for the
operator.
however,
to
can
key
combinations
easi 1y
developer with
be
are
pre-installed,
re-conf i gured
by
the
the simple reassignment of key
IV-SCREEN
--===
Within
aspects
of
DESIGN
===-­
the next four chapters are the more detailed
the
project.
This chapter
concentrates upon
the I/O screen designs used by the data entry routines and
report browsing routines.
Standardized
not only a
screens
---
Standardized
screens
are
benefit to the end-user, but also to both
the
software engineer and the application developer.
interface
the
is of
majori ty
utmost
of
users
importance,
are
due
novices.
to
End-user
the fact
Bei ng
that
abl e
to
consistently find error and status messages and prompts in
pre-set
1oca t ions
ai ds
application program.
is
the
fac t
channeled
through
one
module.
the
opera t i on
of
the
However, the major advantage for the
developers
desired changes in
great 1yin
that all
screen
screen
handl i ng
formatting
module.
can
be
Any
the screen layout are made in that one
Figure 1 is an example of a main menu screen from
an application using the 4GL.
2.9. 38
IV - Screen Design ---
FIGURE 1 - Main Menu Screen:
HODE = Cllllland
-(
HAIN HENU
1EXIT Pr• • = Esc
Fl
=Hanual
8 = CODES
1 = CHART OF ACCTS
2 = ACCOtMING
3 =AUDIT TRAIL
4 = SUPPUERS
5 = CUSTIltERS
6 = ItfJENTORY
7 =SALES
Stl.ct I from about ---)
FILES:
I/O
the
S.cFILE=
Screen
program
then
Curllt=
FO~D=
--- When a
uses
the
• INPUT Int=
mai n menu
standard
Figure 2 and described below.
.-
7
item is sel ec ted,
I/O
screen
shown
in
The following list contains
the description and location of
the standard items in the
screen layout and their reserved areas.
Name
Line
Description of use
Mode
1
Di sp 1ays curren t mode chosen from
the commandline menu.
Command means it is wai t i ng for a
command.
Add or Update are data entry modes
Title
1
displays the title of the
selected from the main menu.
item
.e.g 31
IV - Screen Design
Name
Line
Description of use
Manual
1
always shows how to get the pop-on
manual or help screen
Message
2
displays messages such as error
messages that tell what is wrong
and what to do about it, how to
exit,
special
instructions
for
the current situtation
Work area
4-22 area for entry and data display
Commandline
24
commandline menu
field level prompts
Files
25
number
file
SecFile
25
number of records used in curren t
secondary or re 1at i ona 1 f i 1 e such
as a file containing sold items
related
to a
primary
fi 1 e
of
invoice data
Found
25
number
of
records
found
in
a
search
and
contained
in
the
current search buffer
CurRN
25
record number of record curren t 1 y
displayed on screen (the actual
physical location within the file)
Input
25
prompt area for absolutely every
operator input in these formats:
Byte=
..
Int=
..
Real=
..
Max Length=
(used for strings)
A, C , D, F ,M , R , U, ( examp 1e of c harac t­
er input for commandlines)
of
records used
in
current
.e.g 32
IV - Screen Design --­
Figure 2 -
HODE
I/O Screen Format:
=1111111111
---{ title area
l--message line for errors and exits
Fl
=Hanual
This is the working area used for data display and entry
Line for commandline and field-level praapts
FILES=IIIII SecFILE=11111 FOUND=IIIII CurRN=11I11 IIINPUT 111111111111111111
Figure
3
application
entries.
def i ned
developer
by an
may
app I i ca t i on
transaction.
three
use
all
for
feature
for
data
the en try of an
been
entered.
When
an
entry screen as may be
shows
made
that
columnar-type
example
have
entries are
the column headings.
a
developer
The
transactions
application,
under
demonstrates
It exemplifies an actual
accounting
after
below
on
the
the
screen
In
this
line
directly
the transaction
is saved
by pressing the Fie key, a prompt line is inserted at this
location,
keeping
pushing
them
entries.
1 i nes
4
developer.
on
the
the
previous
screen
as
transactions
templates
The design of the screen within
22,
is
under
On line 24,
the
control
of
is a field-level
down,
for
thus
further
the entry area,
the appl ication
prompt describing
the current field at which the cursor is located.
IV - Screen Design
- - - .Q9
33
Figure 3 - Sample Entry Screen:
HODE = Add
- { ACClHNTIN6
1Fl = Manual
Esc = Canand Line. ENTIN F7 = Del i Fl1 = Save • F2 = CODES
BIT ••••••••••••••
I
••• I
•••••
CREDIT •••••••••••••••••••••••••
Transact r-:- Debit ---, r-- Credit --, r Sourc,"
Date Acct. Mount Acct. Mount Doc Nulbtr
'l'1l'i"7--.-- - - - - ' - - - - - - ' - - - -__ -
88/'·,7,·
II
88/11/11 1111
88111/12 6121
334.52 3121
23.67 un
CGRfnts
___
••••••••••••••••••••••••••••••••
334.52 B6
23.67 CJ( 3241
Beginning Bank Balance
Insurance Pa~t
Enter YearA10nthlDay as 87/ 31 5 --- zeros not n,ussary
2 SecFILE=
Foa.D=
Curllf=
3 .INPUT Byte= 1- 12
FILES::
On
the fourth
is
printed
numbers
are
result
of
app 1 i ca t ion
line above,
in
the
spaces
entered
two
the name of the debit or credit
and
lines
developer.
when
found
of
the
to
be
specific
Th i s
respective
val id.
code
presen ts an
account
Thi s i s a
added
examp 1 e
by
the
of wha t
special features can be accomplished with the 4GL.
Color
on a
Coding --- When the operator sees this screen
color mon i tor,
the data en try area for
the mon th
is
highlighted in yellow to indicate that this information is
what
is to be entered.
Yellow sayS Hdo something!H.
two
bottom
verifiy
lines
also
what
is
to
be
The
entered.
IV -
Col umn
headi ngs
status
data
are
2.9. 34
Screen Design
on
are
The
bottom
the
Entry
brown.
red.
data
mode,
=
"Ft
line are coded
that
Manual",
green.
has already been
and
Titles
is
entered
light cyan while the current data entry field is yellow.
Pop-on
a
coding menu
screen
after
screen
is
Screen --­ Figure 4 shows an example of
Code
screen and Figure S shows an example of
selecting
avai lable
by
a
particular
pressing
the
code
F2
to
key
1 ist.
whi le
Figure 4 -
MODE
•
Sample Coding Menu Screen:
=Add
CODES )
Esc
=exi t Code Win-ire, bIr =11' for !lOre
t = SOURCE DOCIKNTS
3 =CUTOHER CREDIT TEAMS
5 = SAlE CODES
7 = INSTALLERS
Ft
=Manual
I
2 = stfPllER CREDIT CODES
4
=ItfJlMORY r.ATE60RY CODES
6 = SAlEIIN
Enter Code number desired ---) •••
I
I
I
FllES=
Secfile=
FOlND=
CurRN=
3•
INPUT Jot=
8­ 255
This
in
Add or Update mode.
the
the
IV - Screen Design
--- 2.9 35
After selecting the code listing desired (1
for example),
a screen similar to Figure 5 is seen.
Figure 5:
.r
Sample Code Screen
MODE = Add
CODES]
--
CODE
- l ACCOlNTIN6
1Esc = ,xi t Code WindcMi.j'C' blr = ; ; for _or,
DESCRIPTl~
------ -------------------------------
1
1 CH
1 CK
I IN
1 IT
SOURCE DOCIl1ENTS
Cash Transaction
Ch,ck Transaction
Invoic'
Int'l'fst
Fl = Hanual
_
DElETE
-
N
N
N
Y
N
•
FILES=
S,cfi IF
Manual/He1 2
F~D=
Screens
Cur~
3 • IIftT Int=
The
1- 255
on-line
available at any time by pressing the F1 key.
exampl e
of
an
appl ication
4GL general help screen.
specific
manual
is
Below is an
hel p screen and of a
--- 2.9 36
IV - Screen Design
Figure 6:
Application Specific Help Screen
HODE =
F[
II
tWIW. I
- [ ACCOtHTING
1FI = Hanual
Esc = exit Hanual Windlllj space bar = page for .ore
:
• ACCOIlflING
.'
_
EQQ:\TI~
- - - - ASSETS
= r LIABILITIES --, r-- EQUITY -----,
i ncrease Assets: Otcreast Assets UtCrNst I IncrNse DtCrease I Increase
I
NIM Assets
I AcclII Deprec
Paid
Unexpired Insur I Unearneo FItS
PrePaid Expense:
(Advanced Rev)
Received
: Paid
I Payable
Oraliting : Capi tal
ItmtE stJttARY
(tllporary proprietorship)
btcrease Equity I
Expenses
:
Inventory (Btgin)l
Purchasts
:
ContraRlVenue
:
(SalK RetaAl) I
(SalK Discts):
Tran~ort-iR
I
Increase Equit;
Revenues
Inventory (End)
Sales
ContraPurchasts
(Pur RaA)
(Pur Disc)
Uncolltct. Accts :
Henui Add/Update! Find/Data/Clearj
FILE~
67 StctILE=
FOtH)i:
Figure 7:
HOOE=
PaUDj PaOn ---) •
i8 • INPUT A,C,D,F,H,R,U,
23 \;urlN:
4GL General Use Help Screen
lin HINW. I
- [ ACCOtHTING
1FI = Hanual
Esc = exi t Hanual Windlllj space bar = page for .ore
F[
I
Re~orti
,.---, Hoves cursor to
I Tab I NEXT input field
L=.J
• SPECIAL INPUT KEYS
...
.'
fIiil
...
I..-..-J
_
IBlcSpc!
~
Nlllber Keys at
Top of Keyboard
Otletes character
btfore cursorl ~LY
key used to eait
NlttERIC fields
Ctrl
a scrolling scrttn
~
Press Space Bar to continue
WITH S or NIIILock
~uses
,.---, WITH TAB moves cursor
I IShiftl to PREVIOUS input field
I L.-..J
I
I ,.---,
I Alt I
II
Deletes character
above cursor in
text input field
I..-..-J
(D;ll
I..-..-J
I
Menu' AddI!!pdate' Find/Data/Clearj
FILE~ 67 Stc~ILE=
FOUND=
Re~ort·
PaUDj PQOn --) •
INPUT A,C,D,F,",R,U,
23 turAN=
as •
•
IV
2.9. 37
Screen Design
Data
Searches --- From the commandline, the operator
may select RF R for Find to initiate a data search.
8 shows an
examp 1 e
of a
Accounts application.
data search menu for a
If a
option
to
of the fields to search
string field is selected,
select
a
Char t of
Every possible field is listed and
the operator may select one or all
by.
Figure
UBegin-End"
or
I f a n umer i c
described
earlier.
selected,
the operator
is
prompted
the operator has the
RWithin U search
or
to
da t e
enter
fie 1d i s
the minimum
and maximum desired in the search.
Figure 8:
Data Search Menu Screen
"ODE = Search
--I:~RT
II'
1=
6=
11=
16=
21=
OF ACCOINTS]­
EXIT Search l1tnu
Fl
=Esc
SEARCH tINU
ClII@l!t,
2= NoD!l!t!
3= Acc.
7= Jan Total 8= Fib Total
~ln Sal
Hay Total 12= Jun Total 13= Jan Total
Oct Total 17= NOli Total 18= Otc lotal
3rdOtTotal 22= 4thQtTotal
=Hanual
II'
4=
9&
14=
19=
Acct
D!script
lolal
Aug Total 1~ S,p Total
IstQtTotal 21= 2nijOtlotal
~
~
Har Total
11=
42 .INPUT
1-
~r
Ent!r I of ittms to b! search'd ---} ••
FILES:
48 S,cFILE=
FOlND=
Curlt+=
as
22
IV - Screen Design
Search
E.,g 38
Da ta
Wi ndow --- The opera tor may request a
listing of the search criteria used to collect the current
search buffer (just in case one forgot) by pressing 8D 8 in
the commandl i ne.
listing all
Figure 9:
A pop-on search cr iter ia screen appears
limits of the search as in Figure 9 below.
Sample Data Search Screen
-[CIMT OF ACCOOOS)-
MODE = ClINnd
•
Search Data
II
-
Fl = Hanual
••••••••••
1• • • • •E.sc.=.l!X.iiltiifrIliCII.wiii.dcM
SEARCH JTB1
FRIJt (: =begin srch) -
TO
------------------ -------------------- --------------------
3 =Acct NwI
4 =Acct tell!
2...
- 4999
- F
A
II~------------....
I
FILES:
Sl!cfile=
FOlJiD=
CurRN=
3.. INPUT A,C,D,F,",R,U,
IV - Screen Design
Data
search.
been
the
19
be
Reports --- A report may be initiated after a
If
a
repor t i s requested and a
then
executed,
below.
one
is autornaticall y
A search menu
opera tor.
format
2.9 39
The
operator
search
has
not
requested from
is then 1 isted as in Figure
has the option
to see the report
(Figure 11) before executing the report in order to
sure
it
is
the
correct
Following
one.
that,
the
operator may opt to have the search criteria listed in the
headi ng of
the report
Figure 19:
HODE
the
repor t ,
to have page numbers, and to send
to the screen, printer, or both.
Sample Report Menu Screen
=Rtpor t
- [ CWIRl OF ACCOOOS)­
EXIT Search Menu = Esc
I I I REPORT ~ I I I
I = Chart of Accounts
3 = Account Balances - 1st Quarter
5 =Account Balances - 3rd Quarter
7 =Account Balances - Beginning
Enter report number ---} ••
FILES:
48 SecFILE=
FOUND=
FI = Hanual
2 = Account BalanctS - Yearly
4 =Account Balances - 2nd Quarter
6 =Account BalanctS - 4th Quarter
8 = Financial Report
28 CurAN=
.INPUT lnt=
1­
8
IV - Screen Design
Figure 11:
Sample Report Format
MODE = Report
I
11111111
Acctl
2.9 40
-(CIMT OF ACCOlNTS)- KEY to CINTINUE
]=
Account HInt
ACCOIHT IIAl.fW:ES - 1st lINTER
F1
=Hanual
=[
11111111
Balances
1-----------Totals ------------1
January
1st Quarter
Flbruary
Harch
iiiii iiiiiiiiiiiiiiiiiiiiiiii iiiiiiiiii
Iitlilliii
iiialiiiii iilliiiiii
11111 111111111111111111111111 1111111111 1111II1II1 1111111111 1111111111
11111 111111111111111111111111 1111111111 1111111111 1111111111 1111111111
-----
-----------------------­ ---------­ ---------­ ---------­ ---------­
11111 listed
1111111111 1111111111 1111111111 1111111111
=I Page 11111 ] =
FILES=
48 SecFILE=
FOUND=
21 CurAN=
• INPUT
1
-==
V-DEVELOPER
The
between
third
priority
the application
discussion
between
this
in
the
4GL
of
a
4GL
must
developer and
chapter
and
the appl ication
the
time
the
database
spent
area
design
by
of
is
itself
the
the
<records
appl ication
database
establ ished,
the
the
interface
itself.
The
communication
developer
in
terms of
output report
formats,
and
fields>.
developer
anal ysi sand
the
be
the 4GL
involves
parameters which define I/O screens,
and
==­
INTERFACE
installation
shoul d
The
major
now
be
desi gn.
of
Once
the
in
the
parameters
involves the following steps:
1 -
Parameter tables define the base appl ication
for
A - the file data structure
B - the entry screens
C - the output or report formats
Specific, non-standard code is added using
A - the 4GL RmacroR language described later
B - the Turbo Pascal language
C - in 1 i ne and ex terna 1 code allowed through
Turbo Pasca 1 •
2 -
In
phase
1,
the
implementation
through
tables set up
the
4GL
itself
The
structure
these
content
is
The phase 2 method allows for
reading
the
files
the parameter
in standard text
to create
and
of
and
the
same
wi th
is
Phase 2 uses
interface definition
each
files.
method.
greater security and speed in
initializing
internally within the program.
files.
tables
the
file
definitions
v
.1!9 42
Develoger Interface ---
The
I n i ti ali za t i on
provide parameters for
application
developer
initialization of the system.
must
These
include
1 - the location of the data files
2 - The computer type (PC/XT/AT)
3 - video mode
4 - the filler character for entry areas
5 - the client/end-user name
6 - the program name
7 - the logo screen with copyright and date
8 - the option to have the click sound for keys
9 - a
table of the main menu selections and
their related files
The
menu
title
selection
is
en try screen.
is
made,
used
it
is
in
the
used
main
in
the
menu,
and
when
title area
of
a
the
The related files are automatically opened,
managed and closed during the use of that menu item.
I/O
wi th
Screen
the
Defini tions
definition
of
---
the
Screen
window
includes
1
2
3
4
5
6
7
-
The related file number
The upper left corner location
The lower right corner location
Background color
Foreground color
The window frame type number
The title color
defini tions
environment.
start
This
v - Deyeloper Interface ---
Screen
definitions
2.9 43
include a
table of
the
following
data
per source field --­
1 - The source file number
2 - The en try order number (3 for 3rd f i el d
entered in the input sequence)
3 - Field location on the global screen
4 - Field number within the data file
5 - Location of the lower right corner for a
windowed field (as for a multiple line
c ommen t fie 1 d)
The final
of
step in defining a
the work i ng or
the entry screen
screen is the actual
data en try area of
in Figure 3.
the screen,
contents
such as
The column headings and the
data entry area (line 8 in the example) must be created.
File
the
and
database
output/report
c r ea t ed
Def.PAS.
is
f i 1e
routines,
ar e
Field
The
Definitions --- The file structure of
the
and
routines.
in
tab 1 e
file
basis
of
record
The
form
contains
all
specific
management
data
routines,
file
and
record
ina
t ex t
f i 1e
-
and
definitions
ca 1 1 ed
F i 1 e­
the following data pertaining
to a specific file --­
1
2
3
4
5
input
File security code (read/write; read only)
Record size
Number of fields per record
Set of indices indexing the defined file
The major index for the file
v-
--- pg 44
DeveloQer Interface ---
It must be remembered that
the 4GL does reserve menu 8 and
file 8 for the code library described earlier.
File-Def.PAS also
contains
a
table
of
the
following
data pertaining to specific fields within a file --­
1
2
3
4
5
6
7
8
-
Field data type
Field name (used in the search menu)
Field-level input prompt
An upper case flag for string data (yes/no)
Field length internally within the record
Field offset internally within the record
Field minimum and maximum acceptable values
Character set possible for character data
The
final
table
included
in
File-Def.PAS
is another
table containing the definition of the indexing system --­
1
2
3
4
5
-
The source file for the index data
The total number of fields used in the key
The set of ordered fields to create the key
The key size in bytes
A duplicate key flag (yes/no)
Output/Report
reports use the file,
as
parameters
pr oper
data
by
Output
Def i n i ti ons
field,
to
pass
for
and index definitions entered
the appl ication
forma t
formats
to
report formats are contained in a
developer
the
repor t
to
create
rou tine.
the
The
file called Rep-Def.PAS.
It is initialized with a table of --­
1 - Report name
2 - Related menu selection number
3 - Report number
v-
The
Develo2er Interface ---
table
initialization
formats.
2.9. 45
is
f 0 1 lowed
by
the
report
A format is initialized with --­
1 - The report menu number
2
3
4
5
6
-
The report number
Page length of the report/document
Body length of the report/document
The number of records per group
The line spacing between groups
Items 5 and 6 allow,
for example, for the grouping of data
in sets of 5 lines and then double spacing between them for
readability.
The
actual
following manner
body
by
of
the
report
is
created
the appl ication developer.
in
the
Figure 12
gives an example of an accounting report format.
The first
charac ter
the
per
format
1 i ne descr i bes
the use of
1 i ne.
The codes are
T
D
C
1
F
P
-
Title line (No data input into this line)
Divider line (No data input)
Column heading (No data input)
Primary file data line
Footer line (fields are totals or counters)
Page number line
The # symbol
report line.
represents the location of a field within the
v-
e..2 46
DeveloQer Interface ---
Figure 12:
Sample Report Format:
= [ , ......1
ACCOIHT BALmCES - 4th QIWlTER
T
""""
]=
D====================
Account NaIIe
October Nov.uer DecBlber Quarter Bal
C ----- ------------------------ -------.-- -------.-- -------.-- -------.-­
C Acct.
""".,.1
1 "". ••••••••••••••••,....... ••••, ••••, ••, •••11.. ••••••••••
F
F , ••11 listed
F
,.",."., ."""", "",11."
=[ Page 11111
P
l1li Source Data
• Line Source Num
• Num FileSub Flds Source Field Array
·
---- ------- ----
} 5
} 7
1
1
The
lower
2 3 15 16 17 21
8151617
source
content
lines
in
the
2,
works
like
the
for
3,
PRINT
the
numbering
repor t ,
then
16,
USING
in
table above defines
17,
of
1 isted
example,
and
FORM
BASI C.
page
each
is
the
area for the fifth and seventh
seventh
option
the
for
the
the
bot tom
the
fiel ds
line,
1 ike
on
of
The example defines
the
15,
much
field
coun t a t
input
the format.
This
source
part
each
The fifth
numbered
format
data
of
source
array.
page
-- -- -- -- -- -- -- -- -- -- -- -­
.-
6
4
field
as
]=
command
Fi el d
line preceded by the HP H •
source
into
in
the
Turbo
number
9,
represents
of
selected
wi 11
the
i'nput
line
number
in
fiel d
has 6 fields which are
21
page
the primary file
the
at
be
Pascal
the
time
pr i n ted
01"
fi rst
the
repor t •
the
format.
record
If
the
of
the
usi ng
the
v-
Spec i f i c
processing,
is
2.9. 47
Devel02er Interface ---
Code
output)
impossibl e
to
for
final
the
stubbed
and
the
application
The
following
more detail
uses
for
prove).
developer
Turbo
developer
lists
to
Pascal
internal
chapter
and
all
for
I PO
4GL
to
a
the major
(as
the use of
further
customize
commands,
inline
·macros·
the
the
the 4GL system allow
complete
describes
(i npu t ,
however i t
program
Therefore,
procedures wi thi n
application
code,
1ogi c
is embedded into the system,
the market
application.
external
standard
foresee
many versions on
unprotec ted
A
---
the
code,
are available for
the
specific
·macro·
code.
language
in
·macro·
library procedures
be
on 1y
and functions.
Th i s
final
thus
sp ec i f i c c ode
appl ication
greatl y
that
reducing
sh ou 1d
would
the
par t
of
the
possibly require maintenance,
cost
maintaining each application.
the
in
time
and
manpower
for
--===
VI
CODE
This
chapter
concentrates
organization
detailed
of
level
the
of
actual
design
DESIGN
upon
4GL
code
requires
a
the
===-­
design
modules.
data
A
and
more
structure,
an
organization of the code files, and system diagrams.
4GL
Data
the 4GL must
driven,
Structure --- The internal data structure of
be well
compact
limitations
as
designed
enough
for
possible.
in
PCs,
The
order
and
major
as
to
be parameter-
unfettered
structures
with
designed
within the system are --­
1 - The use of the B-tree indexing structure
2 - The use of pointers and linked lists
3 - The direct or absolute addressing of data
4 - The allowance for subscripted arrays of
poi n t er s
t o r ec or ds
f or
men us,
f i 1 es,
fields, indices, and buffers
Dynamically created definition records are used to contain
all
current working data needed for
the current menu
item
selected.
Organization
the Turbo
Pascal
code
per
the
coding
following
of
Code
Files --- Due to the fact that
version 3 edi tor
source code
f i 1e
organization
separate
and
of
for
the
can onl y handl e
organ i za t i on
program
protected code files.
64K of
purposes,
includes
Li sted wi th
the
the
VI - Code Design
2.9 49
file names are the contents of each.
Type-Def.Pas - all
type
declarations
and
a
minimum of global variables
Library .Pas - a
universal
supporting library
con tai n i ng
i ndependen t
modu 1es
used by the entire 4GL program
FileMang.Pas - code for index keys
file management
Pointers.Pas - pointer
management
including
queues,
double
linked
lists,
trees, and buffers
Support .Pas - search menu
print search data window
get report option data
report selection module
data input module
record
management
related
to
data en try
Controls.Pas - the 3 major controling modules
which
call
the
supporting
modules in Support above
EnterRecord
FindData
PrintReport
Menu-Sys.Pas - menu system
Init-Fin.Pas - initialization and finalization
modules
Also included are two application-specific files accessible
to
the
contain
application
the
stubbed
developer.
interface
These
modules
are
for
the
files
that
the developer.
They are
Speciall.Pas - UpDateAcct for accounting modules
any data entry specific tests
Specia12.Pas - any tests required for deletions
specific report tests
VI -
SYstem
the
Diagrams
high-level
Warnier-Orr
logic of
detail
--- R9. 50
Desi~n
Code
logic
diagram.
the program.
for
--- The
and
diagrams
design
Figure
in
a
that
follow present
form
13 contains
simi lar
the most
to
a
general
Figures 14 and 15 continue with more
the Record Menu
Keys section
in
the lower right
corner of Figure 13.
r-
i l !­
ili
11'1;
.Q.9 51
VI - Code Design
Figure 13:
System Structure Diagram --­
r Stt screen
I Get data drive ~raleter (Mhere data Mill bt located)
I Initialize 5 global variables and flags
Initialize global ~ointers for buffers, files, indices, menus
Read defaults and file definitions
I
(currtntly in sequential data file)
Initial- ~ Introduction Screen
ization
I Collect Record Definitions
I Retain origi~l video modej set neM default video lode
I Re9uest ilitdiate update yes/no
Inltalize linUS, file definitions, buffers, and printer codes
I
l
r
ring buffer pointers
Re-initiaTize 5 global flags
II Clear
Close open files to update disk directorr
I Dispose of previous screen definition pOInters
Htnu --4 Hain IUIlU scrnn
I Input neM ltAU selection
~en neM fi Ie set
Create neM entry scrttn and saves current work windows
I
L
r
I Initialize menu variables and pointers
I
Control~ Initialize search record
Loop
I
r
I
I Initialize quit flag
I
I
r
I
I
I Read Only: HtftujFindlDataiClearjReportjPgUpjPgDn
I
I ClIIIIc1ndLi ne-----!
•
I
I
I ReadAlrite:HtftulFindlDataiClearjReportjPgUpjPgDnj
I
I
I
AddIUpdate
I ClIIIIc1nd Loop----!
L
I Tests for mpty filH and buffers
L
I Case key of ---fr Pa9fYP• Key (get prev record data; print fields)
l
I
I
Key (get next record data; print fields)
•
Alt PagtUp Keys (print prev sub pg Mithin record)
Pa~
I
I
I
Alt
~agtDn
Keys (print next sub pg Mithin record)
•
I
I Upda1e (call EnterRecord (lUI»
I
Add. (call
EnterRecord
»
Record
Report (ca II
PrintReport>
Key
•
IMenu
I Clear search buffer
III F'nd data
r
J
II
II
II
L
r
I Window Mhole screen
Finali- -4 Clear screen
zation
I Video set to original video aode
I Be sure all pointers are nil and files closed
L
e
II
represents "exclusive or" or XOR logic
continued in more detail on follOMing pages
(/A
/
I
I
I'
II
I
I'
I
\
t
"
1­
~
VI - Code Design
Figure 14:
2.9 52
System Structure Diagram (continued)
r
I Cl ear r,cord buHrr
I IF add --f Print ,ntry scrttll
I
I Print n~ r,cord nUlbrr
r
Ellt,r
R'cord --I
L
Initializ, r,cord variabl's
r
.
I SIt currtnt ,ntry ii'ld\ location, ii.ld ltngth and oiis.t
I S,t input window ii netOfd ior largr t,xt ii'lds
Entry --I
locat, cursor
Sav, rntry ii'ld screen
·
Initializ' ii'ld variablts
loop
I Fi'ld looP"! Print i.tdiat. input prlllpt
·
I Input routift. according to typ. until grt valid
I PutDatalntoRecord H no qui t flag
I 60to n.xt tntry ii.ld
r
I
I
an~rr
L
rFI8
Sav, (H PostOK i,. H corrKt data thtn SavtData)
I F9 Archiv, ( not currtntly install'd )
Cas, oi I
Functio~ F7
Del,t, (ii dll.tllbl, thtn ask again; print n'xt r,cord)
K,y
I
I F2 Codts pop-on window
I
I Ent'rl1ab = go to n.lt ii.ld in rKord
·
I
t
t ShiHe Tab = go to prtv ii.ld in record
DispoH oi ,ntry r,cord buH,r
r
I Clear rtport iomat buH'r
I Print install'd r,port iONlats
I Gtt report data
I
I
I
I SIt
printR,port1
r
I Search crit'ria in output (ytslno)
I Pag, numb,rs desired (y,51no)j ii y,s, thtn ,nt,r starting pag' nUlb,r
~ PauH b,tw,n pagrs (y,51no)
~ Ch,ck print,r .,ssag'
Ch,ck paOt l,ngth
Increm,nf prinf out nUlbrr
Gtt data r,cord
I
I
r
I
I Print proprr layout iOl'llat
R'cord --f Print r,cord----! Print record totals H applicabl,
loop
I
I Print spicing bttwtn rKords ii applicabl,
I
L
I l1ov' to n,xt search buHrr pointrr
L
Ch,ck pagr l,ngth ior iOMlietd
Dispos, oi report ioraat buiirr and total buii,rs
Rtplac, standard tntry screen
6,t data ircn last acc,sstd search buHrr nodt
Print data r,cord into ,ntry screen
2.9 53
VI - Code Design
Figure 15:
r
I
I
I
I
I
I
ad
System Structure Diagram (continued) --­
Clear search bufftr
r
I Lists all fitlds availablt in rtcord for search
I Input loop of chostn Stt of tlBltnts for tht search
I
r
I
I String/Char (begin or ~ithin starch)
I
I Byttllntegtl'/Real (.iniIUII" IIaxiltllll)
xxListtttnu-l Input loop of search lili tations--l Oatt (.ini... " IIaXillll)
~
I L L
I
r
I
I 6tt search indtx rtquirtd for starch crittria
I
I Find first rtcord nUllbtr in search
, FindData--l Search loop - adds data that INts cri ttria to search bufftr
I
I Prints first rtcord found or Itssa9t of lNONE F0UND1
L
L
Over 1ay
Pascal,
version 3,
in phase 1.
in
Struc ture --- Due to the 1 imi ta t i on of Turbo
the management of overlays is necessary
Overlays were determined to be more efficient
this project
than chaining,
is also possible for
batch
fi 1e
which
the application developer
automaticall y
modules into RAM disk,
an
EXE
due to the code design.
program.
Four
loads all
It
to create a
compi 1ed overlay
therefore nearly giving the speed of
overlay
files
are
used
in
this
projec t .
Overlay
over 1ays
can
logic of a
Design
Methodology
become
qu i te
program.
modules which call
---
The
i nvol ved when
rules
for
using
matched wi th
the
A single overlay file can not contain
any module within
the same overlay code
VI - Code Design
file,
2.9 54
including
itself,
memory
concurrently.
For
should
be
si ze
of
simi 1ar
individual
of
module
largest
reserved
called
in
the
overlay
mai n
modules
preven t
con t i nuous
eac h
over 1ay
within
an
overlay
program memory
should
not
exist
To
not
retain
exist
tradi ng of
for
modu 1es
f i 1e
sh ou 1d
in
a
The size
code
file
swapp i ng
speed,
two
in
or
calling
the modu 1es into
in
the
modules as possible.
modules.
overlay
and
can
eff i c i ency,
memory
contain as many
the
they
because
is
the
more
loop
to
the memory
overlay area for each loop.
One way
to
create an
overlay
system
is
to
create a
columnar table showing the calls or interfaces between only
overlayed
modules.
except for
are
Global
the fact
called.
The
this
that
In
case,
calls
Initialization,
are
not
considered,
they must be declared before they
major
out.
modules
controlling
that
includes
Menu,
and
modules
the main
are
singled
module which
Finalization.
The
first
and last are ignored since they are only called once at the
begi nn i ng and
the end of
any
of
the
the program and therefore can be
located
in
overlay
con trol
loop
1ogi c i s then
con trol
loop
call s
files
conveniently.
the nex t area to consi der.
En terRecord,
Pr i n tRepor t,
and
The
The
Fi ndDa ta
which are the three major operations of the entire program.
VI -
2.9 55
Code Design
A
column
is
then
created for
each overlay file in
design and each column contains the names of
it.
To
make
engineer
For
in
shoul d
example,
the
it
easi er
use
use
input
of
EnterRecord.
color
green
data
One
in
used
PrintReport.
modul es
in
desi gn
coding
the
use
of
the modules in
over 1ays,
wi th
high-light
into
the output
invol ved
to
might
invol ved
by
to
pink
the
the modules
ie.
to
searches,
could
ie.
to draw color-coded
show what
modu 1 e
involved
used by
all
modules
mark
ie.
those
be
used
to
mark
those
used
by
FindData.
Any other modules might be marked with blue.
is
pens.
those
data from the program,
Yellow
sof tware
high-l ighter
program,
another.
To
comp 1 ete
the
the one
that will
be in memory the most.
dominant module should be marked,
may be one dominant module
one for
shou 1d
Fi ndDa ta,
not
be
and one for
more
controlling modules.
between
several
considered.
in
than
If
modules,
one
there
then
perhaps with
each
column for
Pr i n tRepor t •
per
each
is any
perhaps a
of
red.
problem
in
The
There
EnterReport,
However,
the
to
process,
each column must be checked to find the dominant module,
other words,
all
The next step
lines from one module to another
call s
the
there
three maj or
in
redesign
deciding
should be
VI - Code Design
By
file,
may
looking
--- 2.9. 56
for
the
dominant
module
in
each
the speed factor can also be considered.
be
more
efficient
if
it
is
broken
overlay
An overlay
down
into
more
overlays if very many of its modules are called frequently
or
are
con tai ned
that follows,
Ovt/'lay II
in
loops
that
conf 1 i c to
Out/' lay 12
Ovt/'lay 13
Out/'laY 14
i
}
HenulEntryOK ,
HenuIEntryOl<~}
Henu2EntryOK
J
Henu
I
I
I
I
I
CodeWindCM
IlnputData
IEntryOK
OtleteOK
I
II
} EnterRecord
HenulPostOl< ,
I
HtnulPostOK ~} PostOK ---­J
Henu2PostOl< J
f1enu8ScrDtf ,
HenulScrDef ~} CreattEntryScr"" - } f1enu
Htnu2ScrDef J
-,
I
I
I
I
I
J
the diagram
the * indicates the dominant module.
I
HanageFileSet----J
Pointer library
Key library
xxlistHenu
PrintSearchData
SetUp
6etReportData
ReportSelection
In
} FindData
--===
THE
VI I
LIBRARY
===-­
The master support facility for the modules contained
in
the
system
un i versa 11 y
-pseudo
diagram
used
the
protected
code
1 ibrary
procedures and func t ions wh i ch
language-
everything else
is
or
is based.
-macro
language-
Within
of
create a
from
which
this chapter is a
list
of the major library modules.
--- External Call Library --­
PROCEDURE FrameWin (UL,UR,LL,LR,Hor,Ver : Char);
FrameWi n creates a frame around the curren t
using the given characters passed into it.
wi ndow
PROCEDURE GetScrn (
X,Y,NumChars: Integer;
VAR ChAr ray );
ChArray is an untyped variable used to pass in
a
variable sized array of pixel data.
GetScrn gets the
pixel data from the screen star t i ng at posi t i on X, Y
which are global coordinates.
PROCEDURE PutScrn (
X,Y,NumChars: Integer;
VAR ChAr ray );
ChAr ray is an untyped variable used to pass in
a
var i ng si zed array of pixel data.
Pu tScrn pu ts the
pixel data onto the screen starting at posi tion X,Y
which are global coordinates.
FUNCTION GetVideOMode : Integer;
GetVi deoHode retr i eves the
DOS.
curren t
video mode
from
PROCEDURE GotoXYAbs (X,Y: Integer);
GotoXYAbs goes to the global coordinate posi tion
X,Y regardless of the current window.
of
VII - The
2.Q.
LibrQr~
58
PROCEDURE InitVideo (Mode: Integer);
I n i tV ideo i nit i ali z es the video mode to Mode wh i c h
can be 8-7.
Standard settings are:
7 for 88x25 text
and 3 for 88x25 colo~ text.
PROCEDURE SetCu~sorSize (StartLine,EndLine: Integer);
This procedure sets the cursor size 1 ike the BASIC
Locate statement.
FUNCTION WhereXAbs: Integer;
WhereXAbs returns the current
location of the cursor.
FUNCTION WhereYAbs: Integer;
WhereYAbs returns
the
location of the cursor.
current
global
global
screen
column
screen
row
PROCEDURE WriteSt
(St: Str255);
WriteSt is a fast screen access equivalent to Write.
PROCEDURE WriteStLn (St: Str255);
This is a fast screen access equivalent to WriteLn.
--- Window Handling Library --­
PROCEDURE AddWindow (WinNum : Integer;
WTitle : Str88);
AddWindow saves
the current window contents and
current cursor position in a buffer.
It can create a
frame around the new wi ndow and then wi ndow i nsi de
the frame.
It 1 oca tes the cursor at 1,1 in the new
wi ndow and then sets wi ndow colors and clears the
wi ndow screen.
Wi nNum is the number of an array of
window definitions also set up as initialization
parameters by the programmer.
PROCEDURE RemoveWindow (NumToRemove: Integer);
RemoveWindow removes a given number of layers of
windows,
resets
the
final
wi ndow
colors,
and
relocates the cursor to the final
wi ndow'" s
last
cursor position.
VI I
The
--- 2.9 59
Librar~
--- Sound Library --­
PROCEDURE Beep;
Beep merely beeps to get the operator's attention.
PROCEDURE Click;
Click creates a click sound and
InKey below for each key pressed.
is called only
by
--- String Handling Library
FUNCTION UpCaseStr (S : Str255): Str255;
UpCaseStr changes string S to all
in1ine code.
upper
case
using
FUNCTION StrL (Len
: Integer;
Character : Char) : Str255;
StrL returns a str i ng of 1ength Len fill ed wi th
given Character.
the
FUNCTION De1FrontSpc (TLine : Str255) : Str255;
Del FrontSpc returns a string wi th all front spaces
del eted and is used for strings to be converted to
numer i c data because spaces wi 11 create a run-t ime
error.
FUNCTION LSet (Len
: Integer;
Phrase : Str255) : Str255;
LSet left justifies Phrase into a field of length Len
FUNCTION Center (Len
: Integer;
Phrase : Str255 ) : Str255;
Center centers Phrase in a string of length Len.
--- Screen Handling Library
PROCEDURE StatusLine (Which
: Char;
Num
: Integer;
Message: Str255);
StatusLine handles all reserved message areas and
color coding.
Any rearrangement of the screen would
be done here.
VII - The
J!.9. 69
Librar~
PROCEDURE ErrMessage (VAR err
: Boolean;
Message: Str255);
ErrMessage
calls
Beep,
calls
StatusLine
("2" ,9,Message+" - KEY TO CCl'rrINUE), calls InKey to
create a pause and allow for an Esc, and returns the
previous contents of line 2.
PROCEDURE ManualWindow;
This procedure is called any time an Fl is pressed.
It di sp 1ays the manual ina pop-on wi ndow and allows
paging through the on-line manual.
PROCEDURE CommandLine (VAR Command: Char;
CSet
: CharSet;
Message: Str169);
ComrnandLi ne call s Col orCodeLi ne to di sp 1ay a color­
coded commandline message on line 24.
It then calls
CharInput to input a char from CSet and sends Command
character back to be used in a case to determine the
next mode of operation.
--- Input Library --­
PROCEDURE InKey (VAR Special : Boolean;
VAR Charl, Char2 : Char);
InKey loops unti 1 a key is pressed.
If the cl ick
flag is true then it also calls click when a key is
pressed and returns the key that was pressed as 2
characters.
The Special boolean is a flag that is
true if the key pressed i So a 2-code key.
I nKey is
implemented with an MsDos call.
PROCEDURE ReadStr (VAR TStr
: str255;
LMax
: Integer;
which
: Char;
SpecialWindow: Boolean;
VAR BackX, BackY : Integer );
Absolutely all user input is entered through ReadStr
in str i ng form.
ReadStr 1oca tes the cursor; tests
for actual character input and special keys and key
combinations.
VII - The
Librar~
2.9. 61
PROCEDURE Intlnput (
Ins,TabOver: Integer;
VAR IntNum
: Integer;
Bot, Top
: Real;
UnderL, NextLine: Integer;
Promp t
: Str255);
Ins is 8 for a H no insert- option; any other number
tells the program to insert a line at the input
location. TabOver is the column position of the
promp t message.
In tNum is the integer to be i npu t;
if an original value is passed in, then that value is
displayed in the input area.
Bot and Top are minimum
and maximum values allowed.
UnderL is the length of
the underl ine prompt, in other words, the maximum
length of
the input area or maximum number of
characters allowed to be entered.
NextLine is 8 to
flag for no 1 inefeed/carriage return and any other
number sends the cursor to the nex t 1 i ne.
Promp t i s
an input message preceding the input area.
The following are similar and related to Intlnput:
PROCEDURE Bytelnput
PROCEDURE Linelnput
PROCEDURE Datelnput
PROCEDURE Charlnput
PROCEDURE Real Input
·
·
Ins,TabOver
VAR Bite
Bot, Top
UnderL, NextLine:
Prompt
:
(
Ins,TabOver
VAR TLine
Bot, Top
UnderL, NextLine:
Prompt
(
Ins, TabOver
VAR TDate
Bot, Top
UnderL, NextLine:
Prompt
(
Ins,TabOver
VAR TChar
Bot, Top
UnderL, NextLine:
Prompt
(
Ins,TabOver
VAR TReal
Bot, Top
UnderL, NextLine:
Prompt
(
··
·
·
·
·
·
·
·
·
·
··
·
··
··
·
Integer;
Byte;
Real;
Integer;
Str255);
Integer;
Str255;
Real;
Integer;
Str255);
Integer;
Byte3;
Real;
Integer;
Str255) ;
Integer;
Char;
Real;
Integer;
Str255);
Integer;
Real;
Real;
Integer;
Str255);
VII
.e.g 62
The Library
--- Output Library --­
PROCEDURE PrtStat;
PrtStat checks to see if the printer is turned on and
se1 ec t i s on.
I f e i t her i s of f then i t g i ves an
error message and waits for the operator to input to
continue or to exit.
PROCEDURE PrtPrint <Prt
: Integer;
Format: Str255);
Prt is 1 for screen only output,
2 for printer only output, and
3 for both outputs.
If Prt is 2 or 3 then PrtStat is called.
Format is the message to be output with no linefeed.
PROCEDURE PrtPrintLn <Prt
: Integer;
Format: Str255);
This is identical to PrtPrint with a linefeed added.
PROCEDURE FormFeed;
This sends a formfeed to the printer if Prt is
PROCEDURE ColorCodeLine <
Prt
>
1.
: Integer;
: Str255;
LineFeed: Boolean;
Integer );
VAR lk
Prt is 1 for screen output only
2 for printer output only
3 for both outputs
L can contain the characters ,&, or ,~, or " ,
,&, sets bold attributes for printer output and
sets highlighting for screen output.
,-, sets underline on for printer output and
sets low lighting for screen output.
" , turns off all attributes.
LineFeed is true to produce a linefeed.
lk returns an incremented line count if output is to
the printer and Prt > 1.
L
VII - The Library
--- 2.9 63
--- File Handling Library --­
FUNCTION FileLen (DF : Datafile) : Integer;
Fi 1eLen returns the number of records con tai ned in
file DF.
It includes the number of records used and
number deleted and ready for reuse.
FUNCTION UsedRecs (DatF : DataFile) : Integer;
UsedRecs returns the number of used records
current data in the file DatF.
PROCEDURE
This
the
wish
with
Oplnterrupt;
procedure checks for an operator interrupt using
END key.
It call s CommandLi ne to ask
Do you
to ABORT? (Y/N)H. This is used during reports.
H
FUNCTION IndexKey (IndNum : Integer;
RN
: Integer;
VR
: VariantRec);
IndexKey creates the index key for
index number
IndNum using the record number RN and the data
record
contained in VR,
a variant record used to
pass all data records.
PROCEDURE NextKey (VAR IndFile
VAR RN
IndexFile;
Integer;
VAR Key);
Nex tKey goes to the index f i 1e I ndFi 1e to get the
record number, RN,
of the nex t record in the index
and returns the untyped Key for the next record.
PROCEDURE PrevKey (VAR IndFile : IndexFile;
VAR RN
: Integer;
VAR Key);
This is identical to Nex tKey above,
previous record.
but
PROCEDURE ClearKey (VAR IndFile : IndexFile);
ClearKey sets the index pointer to the
empty node of the index.
gets
the
beginning
VII
The
--- 9.9 64
Librar~
IndexFile;
(VAR IndFile
: Integer;
VARRN
VAR Key);
Fi ndKey must be preceded by a Cl earKey command for
IndFile.
It searches for the given index Key in
IndFi leo It finds the first occurance of an exact
match.
PROCEDURE FindKey
PROCEDURE SearchKey (VAR IndFile
IndexFile;
VARRN
Integer;
VAR Key);
SearchKey must be preceded by a ClearKey command for
I ndFi 1e.
It
searches
for
gi ven
index
Key
in
IndFi 1 e.
For
exampl e,
if
IndFi 1 e
has keys of
CATALYST, CATAMOUNT, etc. and Key is CAT, then the RN
associated with CATALYST is returned and Key :=
CATALYST.
It finds the first occurance of the first
par t of a key.
I f none is found then returns a
global flag OK as false;
PROCEDURE ManageFileSet (DoWhat : Char;
FSet
: FileSetType);
DoWhat is either '0' for open or 'c' to close files.
FSet is the set of numbers of the files to be
operated upon.
Indices are automatically updated and
the existence of fi les and indices are tested; if a
f i 1 e or index does not ex i st, the opera tor is asked
if the file should be created.
--- Miscellaneous Modules --­
FUNCTION Yes (Ins, TabOver, NextLine : Integer;
Prompt
: Str255) : Boolean;
Yes call s Charlnput wi th character set of ['Y', 'N']
and returns a boolean value of true if the character
is 'Y'.
PROCEDURE ClrLine;
Cl rLi ne clears
located.
the curren t
1 i ne where
PROCEDURE IntDate (VAR IDate : Byte3);
IndDate returns the system date
information (year/month/day).
in
the cursor
three
bytes
is
of
VI I
--- P..9. 65
The Librar}::
PROCEDURE IntTime (VAR ITime : Byte3);
IntTime returns the system time in three bytes.
FUNCTI(Jo..I Date : Str8;
Date
.... eturns
the
system
data
in
st .... ing
form
system
time
in
st .... ing
form
'00/00/00'
FUNCTI(Jo..I Time : Str8;
Time
returns
the
'00:00:00'
All
wi 11
are
other
not
the
procedures
be
call ed
kernel
of
the program itself.
and
by
the
func t ions are
the
appl ication
system and are
sel f-managi ng and
programmer.
call ed
on 1y
They
by
the
--===
VI I I
TESTING
===-­
Testing of the 4GL must be extensive because it is the
basis of many applications.
To prevent compounding errors,
separate testing stages are as follows:
Stage
1 --- Fi 1e managemen t i s
module to guarantee that all
tested as a
separate
data is saved, retrieved, and
deleted properly.
Stage
2 --- The menuing system and screen handling are
tested with stubbed calls to the file management routines.
This
includes
verifi ed
that
testing
all
the
windowing
screens
It
system.
retain
their
must
be
consistency
according to the design described earlier.
Stage
before
Input
3
integrating
them
routines
into
the
are
Data
tested
Entry
separately
system.
The
major features to be tested include --­
1 -
the error handling for invalid entry of data --­
alphanumeric data entered into numeric fields
numeric data outside of the minimum and maximum
limits
characters not allowed in the field
2 -
the
3 -
the
4 -
the use and clarity of error messages
handl ing
fields
of
the
decimal
point
in
real
data
cursor location, especially in string
using both insert and over type modes
input
VIII - Testing
5 - the
.12.9 67
p~ope~
~etu~n
of
the
input
to
the
calling
~outine.
6 - the detection of special key combinations
The
fi~st
me~ging
them
while
of
standa~d
eve~y
simultaneously
befo~e
Reco~d
modules with an actual
me~ged
type must
updates,
addi tions,
comp 1 eted
be
befo~e
and
test i ng
modules.
Repo~t
5
sc~een
layouts.
tested
at temp t i ng
~epo~t gene~ation
Stage
be
togethe~.
application
del et ions
can
4 --- Testing the
Stage
the
stages
3
modules
layouts
and
coun ts,
col
then
umna~
a~e
now
with
tested
va~ious
totals,
and
with
columna~
pagi ng
a~e
tested extensively.
Stage
accounting
o~de~s,
6
The
application
final
me~ged
testing
with
and point of sale invoicing.
is
a
invento~y,
~elational
pu~chase
--===
IX
SUMMARY
The anal ysi sand
desi gn
p .... esen ted
===-­
is now
he .... e
.... eady
fo .... anothe.... mo.... e detailed stage of design and then coding.
The
4GL
is
••••
not
a
substitute fo
design and p .... oject management.·
been
completed
fo ....
the
6
good analysis,
The majo
application
coding task has
develope.... ,
howeve....
a
tho .... ough analysis and design of the database iteself is the
It will be only as good
top p .... io.... ity befo.... e using the 4GL.
as the database design
majo....
has
functions
been
that
invented
itself.
have
and
the
The 4GL has simplified the
now been automated.
si x
spokes
a .... e
The wheel
the
foll owi ng
management .... outines
1 - Menus and commandlines
2 - Sc .... een management
3 - Data ent y management
4 - Data sea ch management
5 - Repo.... t gene....ation
6 - File and .... eco.... d management
The 4GL now contains f .... om 88 -
9~/.
.... elational
database appl ication.
p.... esented
he.... ein,
the
of the code needed fo .... a
Wi th
application
the modu 1a....
can
be
desi gn
expanded
to
IX -
include
mor-e
application
expanded
both
developer-,
or-
modules
themselves.
of
by
additional
developer.
disturbing
the
structure of
has
user
been
These
primary
maintained.
or
can
the data
goal
of
The secondary
interface has also been maintained
management
struc ture
the
the
modules
4GL
capabi 1 i t i es
ex i st i ng
by
(2)
code added by
the
efficiency
above
the
specific
(1)
Therefore,
consistent
managemen t
the
by
done wi thout
maintenance
wi th
functions
cur-r-ent
be
files
goal
E..9. 69
Summar-i' ---
wi 11
routines.
sti 11
be
screen
for
Any
addi tional
implemented
management,
through
data
entry
management, etc.
The
accep tance
of
past
few
years.
is,
mor-e
advancements
never--endi ng
It
must
spec ia 1 i zed
4GLs
has
however,
be
grown
only
developed
needs of
is also needed for
The quest
on.
fulfill,
keep
up
today and
but a
has
There
thus
one
never
is
been
always
revision
the
Even
wi th
the
tomorrow.
similar approach
systems and many other areas.
for efficient, well-engineered methods still
There
finished.
real-time
wi th i n
the beginning.
to
both
Database management has led the way,
rap i dl y
a
program
another
after
need
another.
the beginning of a new 4GL adventure.
that
is
that
Herei n
goes
totally
it
is
might
on 1y
--===
BIBLIOGRAPHY
===-­
1
Turbo GhostWriter: Taking the Time Out of Turbo
Pascal, This Month's MENU, Vol. 1, No.2, August 1987, pp.
4.
2 paul
Winsberg,
CASE:
Getting the Big Picture,
Database Programming & Design, March, 1988, pp. 54.
3 Jan
Snyders,
The
CASE
Infosystems, March, 1988, pp. 28.
4The Reality
1986, pp. 32.
of
the
of
the
Artful
Dodgers,
Promise, InfoSystems, November,
5 Kent Lawson, Thinking About 4GLs,
January 1988, pp. 28.
Information Center,
6
brochures,
ASCII
(Automated
Software
International, Inc.), received January 1988.
Concepts
7pascal GhostWriter amounts to 'instant software',
Comdex Show Dai 1y, Vol. 5 , No.6, N ovember 2, 1987, pp.
128.
8 James R. Hughes, Moving Out
Infosystems, October 1986, pp. 76.
of
the
Middle Ages,