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1987-01-15
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BASICREF
BASIC CROSS REFERENCE UTILITY Version 1.05
(C)Copyright Excelsior Software, Inc. 1985, 1986
All Rights Reserved
A "User Supported" Program
A PROGRAMMING AID FOR THE IBM PC
EXCELSIOR SOFTWARE, INC.
P. O. BOX 226
NEW MILFORD, NJ 07646
(201) 384-1848
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .
. This User's Manual has been generated from the documentation .
. file BASICREF.DOC on the diskette supplied with the .
. BASIC Cross Reference Utility. A copy of this User's Manual .
. may be produced on your line printer under DOS (when the .
. prompt A> appears) from the program diskette by entering .
. the command: COPY BASICREF.DOC LPT1: . A listing .
. of this User's Manual may also be produced on the screen .
. under DOS by entering the command: TYPE BASICREF.DOC .
. .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOTES ON BASICREF VERSIONS
SPECIAL NOTE ON ALL BASICREF VERSIONS: BASICREF does not recog-
nize path filenames, since the backslash character will be inter-
preted as a delimiter preceding program option characters.
Therefore, all files referenced by BASICREF should reside in the
root directory. Sub-directories will be treated in the future.
Version 1.05 of BASICREF incorporates correction of all known
program bugs as of October 1986.
i
FOREWORD
This disk contains BASICREF, our BASIC Cross Reference Utility
program. We invite you to use the program and copy it freely
for your friends, acquaintances and co-workers so that they may
try it too and, hopefully, pass it on to others.
If you like this program, and find it useful, we request you
send a ten dollar contribution to further the "User Supported"
concept under which this program is made available. In return,
we'll keep you informed of any corrections we make to program
bugs that we become aware of.
On page 26 of this documentation you will find a description
of an enhanced version of the program. Please take the time
to read it. If you like this version of the program, we think
you will like the enhanced version even more so. The enhanced
version is priced at the nominal sum of twenty five dollars
(thirty five if you haven't yet made a ten dollar contribution
for the standard version of the program). If you do order the
enhanced version, you will get:
1. A disk containing the enhanced program and accompanying
documentation.
2. Updates, corrections, modifications, etc. to the program
any time after purchase at nominal cost.
3. Free consultation by mail or phone on any aspect
of the program.
Take the time to read the description of the enhanced version
of BASICREF and, if you are interested, you will find an
order form on page 29 for your convenience. If you try it,
we think you'll be quite pleased.
We are also contemplating rewriting BASICREF for the Microsoft
QuickBASIC compiler. We would like to know how much interest
there would be in such a product, and we would appreciate
hearing from anyone who would be inclined to purchase it if
if were available. The order form includes a space for
indicating interest in a cross reference utility for Microsoft
QuickBASIC. There's no obligation, of course, but it would
help in our deciding whether to go ahead with the effort.
In any event, we would like to hear from you regardless of
whether or not you make a contribution or a purchase. Let
us know what you like or dislike about the program, what you
would like to see added or changed, and any other suggestions
you might care to make or comments you have to offer. You
can reach us at Excelsior Software, Inc., Box 226, New Milford,
NJ 07646.
ii
TABLE OF CONTENTS
NOTES ON BASICREF VERSIONS . . . . . . . . . . . . . . i
FOREWORD . . . . . . . . . . . . . . . . . . . . . . . ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . 1
PROGRAM OPERATION SUMMARY . . . . . . . . . . . . . . 2
SYSTEM REQUIREMENTS . . . . . . . . . . . . . . . . . 3
DISK PREPARATION . . . . . . . . . . . . . . . . . . . 3
PRELIMINARY PREPARATION . . . . . . . . . . . . . . . 3
BASIC Source Program . . . . . . . . . . . . . . . . 3
Cross Reference File . . . . . . . . . . . . . . . . 4
Cross Reference Program Disk . . . . . . . . . . . . 5
Temporary Data File . . . . . . . . . . . . . . . . 6
RUNNING THE CROSS REFERENCE PROGRAM . . . . . . . . . 6
Program Loading and Initiation . . . . . . . . . . . 6
Selection of Choice of Action . . . . . . . . . . . 6
Specification of BASIC Program File Name . . . . . . 7
Input File Options . . . . . . . . . . . . . . . . . 8
BASIC Version . . . . . . . . . . . . . . . . . . . 8
Statement Numbers . . . . . . . . . . . . . . . . . 9
BASIC Program Listing . . . . . . . . . . . . . . . 10
Example of Input File Option Specification . . . . . 10
Specification of Cross Reference File Name . . . . . 10
Cross Reference Printout Options . . . . . . . . . . 12
Example of Cross Reference File Specification . . . 13
PROGRAM OPERATION FOR EACH ACTION SELECTED . . . . . . 13
F1 - Processing of BASIC Source Program . . . . . . 13
F2 - Printout of BASIC Source Program . . . . . . . 15
F3 - List Cross Reference Output on the Screen . . . 17
F4 - List Cross Reference Output on the Printer . . 17
Statement Number References . . . . . . . . . . . 18
Reserved Word References . . . . . . . . . . . . . 20
Program Variable References . . . . . . . . . . . 20
I/O Related Variable References . . . . . . . . . 21
COMMENTS REGARDING COMPILED BASIC PROGRAMS . . . . . . 22
SOME FINAL WORDS . . . . . . . . . . . . . . . . . . . 26
ENHANCED CROSS REFERENCE UTILITY . . . . . . . . . . . 26
DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . 28
PROGRAM ORDER FORM . . . . . . . . . . . . . . . . . . 29
iii
INTRODUCTION
The BASIC CROSS REFERENCE UTILITY is a programming aid for the
serious programmer using the BASIC language on the IBM PC.
Its use will facilitate the programming and debugging of
BASIC source language programs.
The utility provides the following output listings...
1. A complete listing of all program line numbers, showing
all references by other statements in the program. Any
references to non-existent line numbers are given, as
well as any references to invalid line numbers.
2. An alphabetic listing of all reserved words showing the
line numbers in which they appear. Reserved words are
combined when the result provides greater significance
than the individual words would provide as, for example,
in LINE INPUT , ON ERROR , or PRINT USING .
3. An alphabetic listing of all program variables showing
the line numbers in which they appear. Array variables
are shown with their dimensions as defined in the DIM
statement. For a variable whose type differs from its
default value, as a result of a DEFtype statement, the
variable type is shown.
4. An alphabetic listing of all I/O related variables that
are neither reserved words nor program variables. This
includes file names, device names, and descriptors or
delimiters found in I/O statements, such as APPEND
or OUTPUT .
5. A listing of the BASIC source program may be produced,
with top and bottom page margins, page headings, and
formatting of program statements for improvement in
program readability.
Major features of the Cross Reference Utility include...
1. The BASIC source program may include both numbered and
un-numbered statements. The latter is of particular
significance in processing programs to be run under
compiled BASIC.
2. The BASIC program may be processed as either BASIC
Version 1.1, 2.0 or 3.0, for proper differentiation
between reserved words and program variables in each
version.
3. Cross reference output is stored on a disk file, for
listing to the screen and/or printer when desired. On
listing, selected report sections may be suppressed.
4. Last, but certainly not least, this utility will produce
a cross reference listing for any size BASIC program,
without exception. Therefore, your program is limited
only by restrictions of the BASIC system and the BASIC
interpreter or compiler, and not by our utility.
1
PROGRAM OPERATION SUMMARY
The material on this page cuts through all the chaff and gives
the very basic information needed to run the Cross Reference
Utility. This page will get you started; succeeding pages will
provide more detail and may be read at your leisure.
Your BASIC source program should be saved in ASCII format prior
to loading the Cross Reference Utility.
The program is loaded and executed under DOS (prompt A> on the
screen) by typing BASICREF and pressing the Enter key.
Select the actions desired when the main menu is displayed,
using function keys F1 through F4 as toggle switches to
activate or deactivate the selections. Depress function
key F10 when desired selections have been established, to
start processing.
Respond with BASIC source program input file name and/or
cross reference output file name when prompted by the
program. Desired options may be selected by immediately
following the file name with a / or \ , followed
by appropriate one-character option codes, as follows:
BASIC Source Program Input File
1 - Reserved word assignments correspond only to
BASIC version 1.1
3 - Reserved word assignments correspond to BASIC
version 3.0
- Default (neither 1 nor 3) corresponds to BASIC
version 2.0 reserved word assignments
N - Statement numbers in BASIC statements are optional
S - Suppress formatting of BASIC statements in
printout of BASIC source program.
Cross Reference Output File
S - Suppress printout of statement number references
R - Suppress printout of reserved word references
V - Suppress printout of program variable references
I - Suppress printout of I/O related variable references
Processing will start following specification of input and/or
output file names. Actions selected will be executed in
numerical order corresponding to the function key numbers
selected in the main menu. Processing may be terminated at any
time by depressing the F10 key to return to the main menu.
A cross reference output file may be listed in the run in which
it was generated, or in a subsequent run. Options to suppress
sections of the printout may be changed from one listing to
the next. Generated cross reference output files will remain
on the disk until deleted or replaced by another file with the
same name.
Contents of the cross reference output listings, as well as
details on the material presented above, are discussed in the
pages that follow.
2
SYSTEM REQUIREMENTS
The Cross Reference Utility is a programming aid for programs
run on the IBM PC or compatibles under interpreter or compiler
BASIC. The minimum system configuration required is:
128K RAM
One Disk Drive
Monochrome or Color Monitor
Printer (Optional)
This standard version of BASICREF runs under PC DOS versions
1.1 and later. The disk supplied has been formatted and
written under DOS 2.1 as a double sided disk.
The Cross Reference Utility is written in BASIC, and runs
as a compiled program. Your DOS system is the only addi-
tional software required to run the program.
DISK PREPARATION
Before you proceed, it is strongly recommended that you make one
or more copies of the diskette for backup purposes. This can be
done under DOS using the DISKCOPY command to copy the complete
contents of the diskette, followed by the DISKCOMP command to
verify that the source and duplicate diskettes are identical.
The programs can be copied individually from a disk in drive A
onto a formatted blank diskette in drive B with the commands:
COPY BASICREF.EXE B:/V COPY BASICRF1.EXE B:/V
COPY BASICREF.DOC B:/V COPY TESTPROG.BAS B:/V
Programs BASICREF.EXE and BASICRF1.EXE are necessary to
execute BASICREF; BASICREF.DOC is this documentation file;
TESTPROG.BAS is a sample BASIC program.
Once the disk contents have been copied successfully the
original disk should be stored in a safe place.
PRELIMINARY PREPARATION
BASIC Source Program
The BASIC program to be processed by the Cross Reference
Utility must be stored in ASCII format. For a BASIC program
run under interpreter BASIC, the program may be stored on disk
when in memory under BASICA by entering the command ...
SAVE filespec,A
where filespec is a string expression for the file speci-
fication. Note that if the ,A option is omitted, the
program will be saved in a tokenized binary format, which
will not be acceptable to the Cross Reference Utility.
3
A BASIC program file generated through the use of the DOS Line
Editor (EDLIN) program will also be in ASCII format and may be
processed by the Cross Reference Utility. This will be of
particular value in the development of programs to be run
under the BASIC compiler, where the use of line numbers is
optional. (More about this later).
Cross Reference File
When a BASIC program is processed by the Cross Reference
Utility, a disk file is generated containing the information
necessary to produce subsequent cross reference listings.
This cross reference file will be stored on whichever disk
drive the user specifies, and sufficient space must exist on
the selected disk to store the cross reference file.
The exact size of a cross reference file is dependent upon the
size and complexity of the specific BASIC program being
referenced and cannot be easily determined in advance.
However, as a general rule of thumb, the cross reference file
will be less than half the length of the BASIC source program
file, and that criteria can be used to determine if there is
sufficient space on the selected disk to store the cross
reference file that will be generated.
If you do not know whether there is sufficient space on the
disk on which you plan to store the cross reference file that
will be generated, you should proceed as follows:
1. Load DOS from your DOS diskette until the prompt A>
appears.
2. Execute the Directory (DIR) command on the disk that
contains the BASIC source file. (See the DOS manual for
information on applying the DIR command). The space on
the disk occupied by the BASIC source program, in bytes,
will be shown on the line next to the BASIC program file
name.
Assume for example, that the program to be processed by
the Cross Reference Utility is stored on a disk with a
file name of TESTFILE.BAS . Assume that a portion of
the listing produced by the DIR command shows...
FILE1 BAS 12800 8-07-84 9:56a
FILE2 3200 1-11-80 10:04p
TESTFILE BAS 25600 2-03-83 4:13p
PROG EXE 12612 9-04-83 12:12p
In this case, program TESTFILE.BAS occupies 25600
bytes on the disk, and half this amount, approximately,
or at least 12800 bytes must be available on the disk on
which the cross reference file will be stored.
4
3. To determine how much space is available on the disk on
which the cross reference file will be stored, execute
the Check Disk (CHKDSK) command for the selected disk.
(See the DOS manual for information on applying the
CHKDSK command). The status report produced will show
how much free space is available on the disk.
Assume, for example, that execution of the CHKDSK command
produces the following report...
322560 bytes total disk space
9216 bytes in 2 hidden files
204800 bytes in 49 user files
108544 bytes available on disk
262144 bytes total memory
29744 bytes free
In this case, there are 108544 bytes of unused space
available on the disk, far in excess of the 12800 bytes
required, and this disk can be used to store the cross
reference file with room to spare.
Should CHKDSK indicate insufficient space on the selected
disk, repeat step 3 above until a disk with sufficient
space is found.
As will be discussed later, the only limitation on the size
of the BASIC program that can be processed by the Cross
Reference Utility is the disk space available to store the
cross reference output file. Therefore, it is possible to
process a BASIC program that is too large to run under the
BASIC interpreter, or too complex to be compiled by the BASIC
compiler. Consequently, it should be kept in mind that the
successful processing of a BASIC program by the Cross
Reference Utility does not necessarily mean that the program
will be executionable.
Cross Reference Program Disk
The disk containing the Cross Reference Utility programs should
be inserted in the default drive. For a two disk drive system,
it is immaterial in which drive the disks containing the BASIC
program file and the cross reference file are located.
For a single disk drive system, the cross reference programs,
the BASIC program file, and the cross reference file should
all reside on the same disk, for most efficient processing.
If not, it may be necessary to change disks from time to time,
as processing proceeds.
If this situation does occur, the program will prompt for the
proper file, as required. While results will be correct,
processing will be inefficient, and this mode of operation is
not recommended. Therefore, once again, you should see to it
that all required files, including the Cross Reference Utility
programs, reside on the same disk if you are using a system
with a single disk drive.
5
Temporary Data File
The Cross Reference Utility is comprised of the two programs
BASICREF.EXE and BASICRF1.EXE . During the course of
execution of the programs, each program may chain the other.
Because of the compiler options used to generate the .EXE
modules, data cannot be passed between programs through the
use of COMMON statements. Therefore, a temporary data file
is used during the chaining of programs to pass data from one
program to the other. This data file, named BA$ICREF.101 ,
requires about 128 bytes, and only exists while a BASICREF
program is being loaded. This file will, therefore, normally
not be apparent to the user, and is mentioned here only for
information purposes.
RUNNING THE CROSS REFERENCE PROGRAM
Program Loading and Initiation
The Cross Reference Utility can be loaded and run by ...
1. Loading DOS from your DOS diskette until the prompt
A> appears.
2. Inserting the cross reference program diskette in
drive A.
3. Typing the word: BASICREF .
4. Depressing the Enter key.
The BASICREF.EXE module will be loaded and executed.
Selection of Choice of Action
Once the cross reference program is loaded, a title page will
be printed on the screen, and the following menu will appear
on the screen ...
. . . . SELECT CHOICE OF ACTION(S) AS FOLLOWS . . . .
FUNCTION KEY ACTION
------------ ---------------------------------
F1 PROCESS BASIC SOURCE PROGRAM
F2 PRINTOUT OF BASIC SOURCE PROGRAM
F3 LIST CROSS REFERENCE OUTPUT ON THE SCREEN
F4 LIST CROSS REFERENCE OUTPUT ON THE PRINTER
F10 PERFORM SELECTED ACTION(S) OR EXIT PROGRAM
6
Function keys F1 through F4 are used to select the desired
actions. Pressing any one of these keys will turn the
selected action on by highlighting the function key, shown in
the left hand column, with a reversed background. Pressing
the function key again will turn off the selected action. An
action can be alternately turned on and off by continued
depression of the function key.
Pressing any keys other than function keys F1 through F4 or
F10 will have no effect at this point.
When the desired functions have been selected, pressing the
F10 function key will begin program execution, if any of the
function selections F1 through F4 are activated. If none of
the function selections F1 through F4 are activated when
function key F10 is depressed, program execution will end and
the computer will return to the DOS command mode.
If any of the function selections F1 through F4 are activated,
the program will ask for the name of the BASIC source program
file and/or the cross reference file, and will then execute
each of the selected functions in turn.
The program functions are explained very briefly in the ACTION
column in the menu above, and will be described at length
subsequently. Before doing that, however, we will discuss the
specification of BASIC program and cross reference file names.
Specification of BASIC Program File Name
If either action F1, processing of the BASIC source program to
generate a cross reference file, or action F2, printout of the
BASIC source program to obtain a a printed listing, have
been selected, the program will ask for the name of the BASIC
source program file.
The name of the BASIC source program file may be input in
upper case, lower case, or a combination of both, since the
program will convert any lower case letters to upper case.
The filename that is input in response to the program prompt
will be treated in the same manner as BASIC would treat it.
If the filename extension is omitted, the program will assume
an extension of .BAS , so that a response of TESTFILE
would be interpreted as TESTFILE.BAS . If there is no
extension associated with the filename, the name should be
entered with only the period following the name as, for
example, TESTFILE. .
When typing of the filename is complete, press the enter key.
If no characters have been typed, the program will ask for the
file name once again.
The disk on the default drive, or on the drive specified in
the filename, will be searched for the specified BASIC program
file. If the file is not found, or if the file is null, an
appropriate message will be printed on the screen, and the
program will ask for the input file name once again.
7
If the file is found, the program will check to verify that
the input file is an ASCII file. If the "N" option has not
been selected (see discussion below on input file options) the
first record will be checked to see if it starts with a number
in the range of 0 to 65529. If it does not, a message will be
printed on the screen that the file is not an ASCII file, and
the program will return to ask for the input file name once
again.
If the "N" option has been selected (see discussion below on
input file options) the first record will be checked to see if
it starts with a number, an alphabetic character (A-Z or a-z)
or a blank. If it does not, a message will be printed on the
screen that the file is not an ASCII file, and the program
will return to ask for the input file name once again.
If the selected input file is found to be in the proper
format, the program will ask for the cross reference file name
(as discussed below) and/or proceed with processing.
It should be noted that here, and throughout program
execution, pressing the F10 key will cancel all processing and
return to the main menu for reselection of program options.
Input File Options
There are three options available relating to the processing
of the BASIC program input file. The options are invoked by
entering as part of the input file name, immediately following
the filename specification, a slash / or backslash \ ,
followed by the one-character option code or codes. The
option codes may be entered in either lower or upper case, in
any order, with intermediate characters if desired to separate
the option codes. Only valid option codes will be processed;
any invalid option codes will be ignored.
The input file options are as follows...
BASIC Version
Option: 1 or 3 . Default value (blank): 2
The BASIC version option specifies which version of BASIC
applies, for proper differentiation between reserved words and
program variables. If no option is given, the default value
of 2 is applicable, i.e., BASIC 2.0 reserved words are
assumed. Options 1 and 3 specify BASIC versions 1.1 and 3.0,
respectively.
The choice of options determines whether certain variables are
classified as reserved words or program variables in the cross
reference listing. Assume, for example, that a BASIC program
contains the following variables, among others:
VALUE
INPUT
WINDOW
ENVIRON
Regardless of the option, in all versions VALUE will be
considered to be a program variable while INPUT will be
considered to be a reserved word.
8
If option 1 has been selected, for BASIC version 1.1, both
WINDOW and ENVIRON will be considered to be program
variables. If no option has been selected, so that BASIC
version 2.0 applies by default, or if option 3 has been selected,
for BASIC version 3.0, both WINDOW and ENVIRON will be
considered to be reserved words.
(It should be noted that the BASIC Version 3.0 reserved words
ENVIRON , ENVIRON$ , ERDEV , ERDEV$ , IOCTL , IOCTL$ , AND
SHELL are also reserved words in BASIC Version 2.0, although
undocumented. Therefore, BASICREF will consider them to be
reserved words in either case, and the default option and /3
option output will be identical).
Similar differentiation will exist for other reserved words
that exist in one version of BASIC and not in another.
Obviously, if all reserved words in a program exist in all
versions of BASIC, it is immaterial which option is chosen.
The BASIC version option selected will apply to any listing
of the cross reference file. To change options, a new cross
reference file must be generated for the source program.
Statement Numbers
Option: N : Statement numbers optional
Default value (blank): Statement numbers required
Interpreter BASIC requires each statement to have a statement
number, and this condition will apply if the default option is
invoked. In this case, the program will generate a message
that the input file is not an ASCII file if the first
statement in a BASIC program is un-numbered, or a message that
there is a direct statement in the file if the first statement
is numbered but a subsequent statement in un-numbered. In
either case, processing will terminate and the program will
return to the main menu.
In compiler BASIC, the statement numbers are optional, being
required only for branching. If the N option is selected
(the same parameter as used to invoke the option with the
BASIC Compiler), the program will accept statements with or
without statement numbers. In this case, the program will
generate a message that the input file is not an ASCII file,
and will return to the main menu, if the first character of
the first statement in a BASIC program is not a number, letter
or blank, but no checking for statement numbers will be done.
Selection of the N option will apply to the specific run
during which the option is invoked. In subsequent runs, when
either listing the BASIC program or generating the cross
reference file, the N option must be respecified, if
applicable.
This option is of particular value for large programs that may
be taxing the capabilities of the BASIC compiler, and more
will be said about this subsequently.
9
BASIC Program Listing
Option: Default value (blank) : Formatted listing
S : Unformatted listing
The BASIC source program may be listed by selecting the F2
option in the main menu. All listings will be generated with
top and bottom margins, page numbering and page headings.
Additionally, as discussed subsequently, unless otherwise
specified, some formatting of statements will be done to
improve program readability.
This formatting can be suppressed by the S option. In
this case, each program statement will be printed as it would
appear if printed with an LLIST command with an 80 column
page width.
Selection of the S option will only apply to the run in
which it is evoked. If subsequent listings are desired with
suppression of formatting, the S option must be reinvoked
at that time.
Details of the program listing will be discussed subsequently.
Example of Input File Option Specification
The following specifications will all invoke the same input
file options for a BASIC program named TESTFILE.BAS , for
example, in response to a program prompt for the input file
name:
TESTFILE.BAS/1NS
TESTFILE\1/S/N
TESTFILE/ N S 1 X
TESTFILE.BAS//3\\s//n\\1
In the third case, the parameter X has no meaning, and
will be ignored. In the fourth case, both BASIC versions 1.1
and 3.0 are specified. Where this redundancy occurs, the
rightmost specification will govern, and in this case BASIC
version 1.1 will apply.
Specification of Cross Reference File Name
If either action F1, processing of the BASIC source program to
generate a cross reference file, or action F3, printing the
cross reference listing on the screen, or action F4, printing
the cross reference listing on the printer, have been
selected, the program will ask for the name of the cross
reference file.
The cross reference file name may be input in upper case,
lower case, or a combination of both, since the program will
convert any lower case letters to upper case.
10
If action F1, processing of the BASIC source program to
generate a cross reference file, has been selected, regardless
of whether actions F3 or F4 have been selected, a new cross
reference file will be produced, and the file name input will
be the name of the new file. If action F1 has not been
selected, a listing will be made of a previously produced
cross reference file, and the file name input must be the name
of a cross reference file that already exists on the disk.
In responding to the prompt for the cross reference file name,
if the filename extension is omitted, the program will assume
an extension of .REF , so that a response of TESTFILE
would be interpreted as TESTFILE.REF . If there is no
extension associated with the filename, the name should be
entered with only the period following the name as, for
example, TESTFILE. .
If a BASIC source program input file was specified previously
in the run, as a result of choosing either the F1 or F2
options in the main menu, the program will assign a default
name to the cross reference file if you do not specify a
filename at this point. In this case, the extension will be
changed from what it is in the BASIC source program input file
(usually, but not necessarily, .BAS ) to .REF . For
example, an input file named TESTFILE.BAS would result in
a cross reference file named TESTFILE.REF .
When typing of the filename is complete, press the enter key.
If no characters have been typed, the program will either
ask for the cross reference file name once again, until one is
supplied, or assume a name as specified in the paragraph
above.
If a BASIC source program input file was specified previously
in the run, as a result of choosing either the F1 or F2
options in the main menu, the program will first check to see
if the cross reference filename is different from the BASIC
source program filename. If the names are the same, a message
will be produced to inform you that the names must be
different, and the program will request the cross reference
filename once again. (Note that the same name will occur if
the program generates the cross reference filename and the
input file is named with an extension of .REF ).
The disk on the default drive, or on the drive specified in
the filename, will be searched for the specified filename. If
a new cross reference file is to be generated, because the F1
option was selected in the main menu, and the specified
filename does not exist on the disk, the program will assign
this name to the new cross reference file, and processing will
proceed. However, if a new cross reference file is to be
generated and a file with the specified filename already
exists on the disk, the program will inform you of that fact
and give you an opportunity to change the name of the cross
reference file that will be generated. You should note that
if you give the cross reference file the same name as that of
a file already on the disk, the contents of the original file
will be lost.
11
If a new cross reference file will not be generated, because
the F1 option was not selected in the main menu, the named
file must exist on the disk. If the file is not found, an
error message will inform you of that fact, a request will be
made for the cross reference filename, and the disk will be
searched again until the file is found. When the file is
found, the program will check to determine if the file is a
complete cross reference data file. If the file is either not
a cross reference data file, i.e., the file was not generated
by the Cross Reference Utility, or the file is not complete,
i.e., a run was aborted before the complete file was
generated, an appropriate error message will be printed on the
screen and the program will ask for the cross reference file
name once again. When an acceptable cross reference file is
found, the program will proceed with subsequent processing.
As was mentioned earlier, it should be noted that here and
throughout program execution, pressing the F10 key (and the
enter key if the program is asking for a filename) will cancel
all processing and return to the main menu for reselection of
program options.
Cross Reference Printout Options
There are four options available relating to the printout of
the cross reference listing. The options are invoked by
entering as part of the cross reference file name, immediately
following the filename specification, a slash / or back-
slash \ , followed by the one-character option code or
codes. The option codes may be entered in either lower or
upper case, in any order, with intermediate characters if
desired to separate the option codes. Only valid option codes
will be processed; any invalid option codes will be ignored.
The option codes provide for the suppression of sections of
the cross reference listing printout. This may be of interest
in large programs where you may not be concerned with the
complete information that could be listed. The options will
only be in effect during the run in which they are invoked;
sections may be suppressed in one run and then printed in a
subsequent run by omitting the particular option code.
The cross reference printout options are as follows...
S Suppress printout of statement number references
R Suppress printout of reserved word references
V Suppress printout of program variable references
I Suppress printout of I/O related variable references
The default for each is equivalent to omitting the option
code, i.e., each section will be printed unless specified
otherwise by the option code.
Any options selected will apply to listings produced on both
the screen and the printer.
12
Example of Cross Reference File Output Specification
The following specifications will all invoke the same cross
reference listing suppressions for a cross reference output
file named TESTFILE.REF , for example, in response to a
program prompt for the cross reference file name:
TESTFILE.REF/RI
TESTFILE\I/R
TESTFILE/ R I Z
TESTFILE.REF//r\\i//
In all four cases, TESTFILE.REF is the cross reference
output file, and the reserved word and I/O related listings
are to be suppressed. In the third case, the parameter Z
has no meaning, and will be ignored.
If the F1 option had been selected in the main menu, to
process a BASIC source program file, and neither option F3, to
list the cross reference output on the screen, or option F4,
to print the cross reference output on the printer, had been
selected, all the parameters in the four specifications above
would be ignored since cross reference listings would not be
produced in that run.
PROGRAM OPERATION FOR EACH ACTION SELECTED
F1 - Processing of BASIC Source Program
If the F1 option had been selected in the main menu, to
process the BASIC source program, i.e., to generate a cross
reference file for the BASIC program, processing will begin
immediately after the input and output file names have been
specified.
Each statement in the BASIC source program will be processed
in sequence. The first 79 characters of the BASIC statement
will be shown at the bottom of the screen in reversed image
as the statement is being processed.
Since the Cross Reference Utility is not a preprocessor, the
BASIC statements are not checked for errors. However, in the
course of classifying variables as to type, errors involving
useage of reserved words may be found and, if so, an error
message will be printed on the screen.
The following conditions will result in an error message being
printed:
1. A reserved word appearing in a COMMON statement.
2. A reserved word appearing in a DIM statement.
3. A variable name that is a reserved word with a
type declaration character ($,%,!,#) at the end.
In each case, the error message will be:
SYNTAX ERROR IN STATEMENT XXXXX
13
where XXXXX is the number of the BASIC statement in which the
error appears. If the /N option is in effect and the
statement with the error is un-numbered, the value of XXXXX
will be that of the most recent statement number. If there
was no previously numbered statement in the program, the
value of XXXXX will be 0.
While the improper use of a reserved word name will be flagged,
the variable used in this way will appear in the Variable
References listing output discussed subsequently.
The program will also print a warning message if command type
statements are encountered under certain circumstances. The
warning message will be:
** CAUTION ** - STATEMENT NO. XXXXX CONTAINS A COMMAND... YYYY
where XXXXX is the number of the BASIC statement in which the
command type statement appears, and YYYY is the command type
statement.
This caution will not be printed if the command type statement
is anticipated, such as the commands MERGE or DELETE
in a CHAIN statement, or if the command type statement
is encountered in a DATA statement.
Regardless of whether a caution is issued, the command will
appear in the Reserved Word References listing output discussed
subsequently.
Processing of the BASIC program will continue until all state-
ments have been processed, or until the single-step capacity of
the Cross Reference Utility has been reached. When this occurs
variable references and statement number references will be
sorted internally by the utility, and the data will be written
onto the cross reference file. Comments at the bottom of the
screen will inform you as to the program status.
In most cases, the end of your BASIC program will occur before
the capacity of the Cross Reference Utility is reached. In
practice, BASIC programs in excess of 1000 lines of coding have
been within the capacity of the Cross Reference Utility to
process in one pass. However, the size of your program need
not be of concern during processing. If the capacity of the
utility is reached, the sorting and writing to the disk will
be done in stages, with appropriate merging of the data between
stages. As before, comments at the bottom of the screen will
inform you as to the program status.
Processing of the BASIC program in stages, if necessary, is done
automatically by the Cross Reference Utility and will require no
action on your part. Although messages at the bottom of the
screen will show when intermediate sorting or merging is being
done, at the conclusion of processing there will be no differ-
ence between a cross reference file generated in a single pass
and one generated in more than one pass.
As mentioned earlier, programs in the order of 1000 statements
may be processed in one pass. In practice, a maximum of two
14
stages has been necessary to process very large BASIC programs.
In actuality, the Cross Reference Utility can process any size
BASIC program, ad infinitum, in any number of stages necessary.
Typically, however, the utility will process a BASIC program
in one stage most of the time, and will not exceed two stages
in just about any conceivable case.
At the conclusion of processing of the BASIC program, the cross
reference file will be written with information including the
date and time. The date and time will correspond to that when
processing of the BASIC program was initiated. The date and
time will be established on the cross reference file, and this
date and time will appear whenever the established cross refer-
ence file is listed.
As with anytime during the running of the cross reference
utility, processing of the BASIC program may be terminated
by depressing the F10 key, in which case the program will
return to the main menu. If this is done during processing
of the BASIC program before any data were written to the disk,
the cross reference file will be null, i.e., the file will
have a length of 0. If this is done after some data have
been written to the disk, but before all data are written to
the disk, the file will be incomplete. In either case, a
subsequent attempt to list the cross reference file will
result in an error message that the file is not complete.
An incomplete cross reference file will also result if there
is insufficient disk space for the complete file. This will
not occur if sufficient space is assured on the disk, as
discussed earlier.
At the conclusion of normal processing of the BASIC program,
the Cross Reference Utility will list the source program or
the cross reference output, if the appropriate options were
selected, or else return directly to the main menu.
F2 - Printout of BASIC Source Program
If the F2 option had been selected in the main menu, to print
the BASIC source program on the printer, printout of the
program will be done following the processing of the BASIC
source program, if applicable.
All printer output will be made assuming 8-1/2 x 11 page size
with 80 column printout and 6 lines to the inch. Printing
will start at the line where the print head is positioned, so
that the top margin will be determined by the setting of the
paper in the printer. The top and bottom margins will total
6 lines, approximately. (A BASIC statement that runs for
more than one line will always have all lines appearing on the
same page. The bottom margin may vary, therefore, to prevent
a statement from being split between two pages).
All pages will be headed with the BASIC program file name, the
date and time, and the page number, in the following format
(spacing is reduced here, for illustrative purposes)...
15
BASIC Program file: TESTPROG.BAS 11-07-84 01:12:23 PAGE 1
If both the F1 and F2 options were selected in the run, the
date and time shown in the program listing will be the same
as the date and time established in the cross reference file.
If the F1 option was not selected, the date and time shown in
the program listing will be the date and time the program
listing was started.
If formatting of the BASIC program is being suppressed, by
the use of the /S option in the BASIC program input file
name, each statement will be printed as it would be printed
by the LLIST command. In the sample BASIC program on
this disk, TESTPROG.BAS , statement number 110, for
example, would be printed with the /S option as:
110 IF A < 0 THEN 60 ELSE IF A=0 THEN CLOSE:END ELSE PRINT A
If the /S option has not been invoked, some formatting
will be done to improve program readability. In this case,
statement number 110 would appear as:
110 IF A < 0 THEN 60_
ELSE IF A=0 THEN CLOSE:END_
ELSE PRINT A
An underscore at the beginning or end of a line indicates that
that position was blank in the unformatted statement.
Additional formatting will be performed on statements that
extend over more than one eighty column line. This may be
observed in any such statements that exist in a program.
If the /N option was invoked, each BASIC statement will be
preceded by a line number, which will correspond to the EDLIN
line number for that statement. (Column headings in this case
will show that this is a line number). Statement 110 above
would then appear as:
11 110 IF A < 0 THEN 60_
ELSE IF A=0 THEN CLOSE:END_
ELSE PRINT A
The sample (although trivial) BASIC program TESTPROG.BAS
on this disk may be listed with various options to observe
the differences in output.
Listings produced with the F2 option in the main menu will
only be generated on the printer. If a program listing on the
screen is desired, the BASIC program should be loaded under
BASICA and the LIST command executed, or a listing may be
produced under DOS using the TYPE command or EDLIN.
At the completion of the BASIC program listing, the cross
reference program will return to the main menu if no other
processing options have been specified, or else will perform
the next program step in turn.
16
F3 - List Cross Reference Output on the Screen
and
F4 - List Cross Reference Output on the Printer
The two options will be discussed together because they are
quite similar in appearance.
A listing will be produced on the screen if option F3 had been
selected, and on the printer if option F4 had been selected.
If both options were selected, a screen listing and a printer
listing will be produced essentially simultaneously.
If option F1 had been selected in the same run, then the cross
reference listing produced will correspond to the BASIC source
program previously processed in that run. It should be noted
that if option F2 had been selected in the run, but option F1
had not been selected, the BASIC source program listed under
option F2 will not necessarily correspond to the cross reference
listing that is being produced.
All printer output will be made assuming 8-1/2 x 11 page size
with 80 column printout and 6 lines to the inch. Screen output
will be 80 columns wide.
All output will be listed with the same page headings that were
shown under the F1 option. Individual column headings describe
the contents of each output section. Since the page length is
different for the screen and printer, page numbers will differ
on the two output media for the same program, except for the
first page.
If listing is being made on the printer only, printout will be
continuous, and will end only when the report is completed. If
listing is being made on the screen, the listing will pause at
the end of each screen page. If listing is being made on the
screen and printer simultaneously, the printer listing will
pause while the screen listing is in a pause state.
When the screen is in a pause state, pressing the space bar
once will continue the listing until the end of the next page
is reached, and so on. If the space bar is pressed twice,
within a period of 1/2 second, subsequent printing will be
continuous, without a pause at the end of a screen page. When
printing continuously, depressing the space bar once will cause
the resumption of the pause at the end of a screen page. This
cycle may be repeated as often as desired during the report
printout.
Each of the four sections of the cross reference report may be
suppressed individually, as was discussed earlier, by selection
of control characters in the cross reference file specification.
A section suppressed in a run may be subsequently printed out
by omitting the appropriate control character.
Assuming the sections have not been suppressed, they will be
printed in the order discussed in the sections following...
17
Listing of Statement Number References
Each statement number in the program will be listed, along with
the numbers of any statements that reference each. If any
statement is un-numbered, it will assigned the most recent prior
statement number. If there is no prior numbered statement, the
un-numbered statement will be assigned a statement number of 0.
The statement number reference section for the sample program
of TESTPROG.BAS will be as follows...
Statement Reference
10
20
30
40
50
55 55 55
60 110
70
80
90
100
110
120
130
140
150 170
160 50
170
180* 160 160
190* 160
***** 160
*Statement number does not exist
*Reference to invalid statement number
If no entry appears alongside a statement number, that statement
is unreferenced. As in statement number 55, a statement may
reference itself. If a given statement references another more
than once, the statement number is repeated under References, as
is the case for references to statements 55 and 180.
18
For any references to statements that do not exist, the non-
existent statement is listed followed by an asterisk, as are
statements 180 and 190. A note that the statement does not
exist is printed on the page on which the non-existent statement
appears.
For a program containing the statement RESUME 0 that does
not have a statement numbered 0, the non-existent statement
number message will be produced. Although the RESUME 0
statement is valid, this treatment is consistent with that
of the BASIC interpreter, which would give an "Undefined line
number" error if you try to renumber a program under these
conditions. An ON ERROR GOTO 0 statement will be treated
the same way by the program, although the BASIC interpreter
would treat it differently.
For any references to invalid statement numbers, such as the
reference to statement number 78000 in statement 160, the last
entry in the list of statement numbers will be ***** , with
the referencing statement numbers being shown. A note that there
is a reference to an invalid statement number is printed on the
last page of the statement reference report.
Programs generated with the BASIC interpreter cannot have any
duplication of statement numbers, since the BASIC system will
replace a statement with a subsequent statement that has the
same statement number. However, a program to run under the
BASIC compiler may have been generated through the use of the
EDLIN utility and, conceivably, could have erroneous duplication
of statement numbers. In this case, the Reference field would
show the duplication of statement numbers. For example, a
line that read...
75 35 DUPL 110 120
would mean that statement number 75 is referenced in statements
35, 110 and 120 and, in addition, there is another statement
number 75 in the program.
Statement numbers appearing in a CHAIN statement will be
referenced here if the statement numbers apply to the current
program, but not if they apply to the chained-to program. For
example, in the statement:
CHAIN MERGE "A:PROG1",1000,DELETE 2000-3000
statements 2000 and 3000 will be referenced because they apply
to the current program, but statement number 1000 will not be
referenced because it specifies a line in the chained-to
program.
Following the printout of the statement number references, a
listing of reserved word references is made.
19
Listing of Reserved Word References
The next section printed is a listing of all reserved words in
the BASIC program and the statement numbers in which they
appear. For the sample program of TESTPROG.BAS a section
of this listing (not consecutive) would be...
Reserved Word Reference
BEEP 160
CLOSE 110 150
ERR 160 160 160 160 160
ON ERROR 50
PRINT USING 100
PRINT# 160
A word appearing more than once in a statement will have the
same reference repeated, as is the case for ERR above.
Reserved words that have more significance as compound words
rather than as individual words are shown in the compound form,
as, for example, ON ERROR and PRINT USING above.
For a reference to a function, as in DEF FNXXX , the entry
in the reserved word listing will be DEF FN and in the
program variable listing will be FNXXX .
Reserved words will be listed in this section regardless of
how they are used. For example, the reserved word FOR is
used differently in statement 60 than in statement 120, 130 or
140, but all four references will be listed together.
Reserved words that differ from one version of BASIC to another
will be classified in accordance with the applicable version of
BASIC that was specified with the BASIC source program filename
when the cross reference file was originally generated.
The listing of reserved word references will be followed by a
listing of the program variable references.
Listing of Program Variable References
A listing of program variable references will follow, unless
the listing is suppressed. For the sample program of
TESTPROG.BAS , the variable reference listing will be..
Variable Reference
A 90 100 110 110 110
A(20) 40 70 70
B(2,5) 40
C(100) [$] 40
G$ 55 55 55
I 60 70 70 70 80
The first variable A is different from the second variable,
which is a subscripted variable. This second variable was
dimensioned as 20 in a DIM statement. Similarly B was
dimensioned as 2,5 in a DIM statement and C was dimensioned
as 100 in a DIM statement. A variable appearing, for example,
as D() would have been dimensioned from use as a subscripted
variable in a statement without a corresponding DIM statement.
20
A bracket following a variable name means that the variable is
defined as other than its default type. C(100) [$] means, for
example, that dimensioned variable C is defined (through the use
of a DEFtype statement) as a string variable, rather than its
normal default type of a single precision variable.
The variable types that may appear within the brackets are:
[I] Integer
[D] Double precision
[$] String variable
Note that a single precision variable does not appear within
brackets, since a variable that is not shown with a bracketed
type and does not have a rightmost character that is a type
delimiter (!,#,%,$), must be a single precision variable.
In a similar vein, any variable that has a rightmost character
that is a type delimiter will never be shown with a bracketed
type, since a type delimiter always takes precedence over a
DEFtype statement.
A variable shown in a DEF FNXXX statement will be listed
here with a variable name of FNXXX .
The listing of program variable references will be followed
by a listing of I/O related variable references, if any.
Listing of I/O Related Variable References
The last section of the cross reference listing will show
I/O related variable references, if any. For the sample
program of TESTPROG.BAS , for example, the listing is...
I/O Related Reference
"KYBD:" 140
"LPT1:" 130
"SCRN:" 120
AS 120 130 140
OUTPUT 120 130
Any device name or file name will appear here. Similarly the
descriptors AS and OUTPUT , when used in an OPEN
statement, will appear here.
Differentiation should be noted between the names appearing
above and similar names that may be reserved words or program
variables. For example, KYBD: is a device name while
KYBD used in a statement would be a program variable.
The words AS and OUTPUT as used in an OPEN statement
are neither reserved words nor variable names; the same words
used in a different context would be program variables and would
appear in the program variable reference section.
21
As an extreme case, consider the following line of coding:
1000 OPEN "OUTPUT" FOR OUTPUT AS #1:OUTPUT=12
This would generate three entries for OUTPUT , each with a
different meaning...
"OUTPUT" as a filename in the I/O Related Variable References
OUTPUT as a descriptor in the I/O Related Variable References
OUTPUT as a variable name in the Program Variable References
Note that the word INPUT in statement 140 does not appear
here. Since it is a reserved word, it appears in the reserved
word reference section.
The listing of I/O related variable references concludes the
output of the cross reference listing.
Following the end of the cross reference listing, the utility
will return to the main menu. Additional processing may then
be done, or an exit back to DOS may be made.
COMMENTS REGARDING COMPILED BASIC PROGRAMS
Having made mention of compiled BASIC programs several times,
it behooves us to make some comments in this regard. This
would seem to be an appropriate point.
Anyone who has worked with BASIC for any period of time must
surely be aware that interpreted BASIC can be excrutiatingly
slow. For programs of any substance, execution time can be
a severe impediment. In many cases, serious consideration
should be given to converting programs from interpreted BASIC
to compiled BASIC. The increase in speed can vary from a small
factor to a very major improvement.
As an example of the speed advantage of compiled BASIC over
interpreter BASIC, we refer you to the article "Four FORTH's"
in the April 1984 issue (Vol.2, No. 5) of PC World magazine,
and our letter on page 26 of the September 1984 issue (Vol 2,
No. 10) of the same magazine. We pointed out that the timing
for a program to calculate prime numbers (The Sieve of
Eratosthenes) decreased from 539 seconds under interpreted BASIC
as reported in the article on FORTH, to 11 seconds when run with
compiled BASIC. This difference is, admittedly, extreme but
is indicative of what can happen.
The discussion that follows was written when we were using
the IBM BASIC compiler and EDLIN. Like many others, we have
gone on to bigger and better things. We now use Microsoft's
QuickBASIC exclusively, and have graduated to a full screen
editor. So take what follows with a grain of salt. (Along
this line, we would appreciate your letting us know if you
would be interested in a cross reference utility for the
QuickBASIC compiler. Please see the order form at the end
of this documentation).....
22
We typically develop a program in interpreted BASIC for its
greater ease in testing and debugging. We maintain a version
of the program with appropriate changes for compiler BASIC as
we go along. This allows us to develop the compiled version
in parallel with the interpreted version.
Eventually, with a program of any substance, we run into a
problem with the compiled version of the program. We start
getting nasty TC messages during compilation, telling us
that the program is too complex. The problem invariably is
a result of too many statement numbers exceeding the capacity
of the compiler. The excess of statement numbers is a carry-
over from the fact that interpreter BASIC requires every
BASIC program statement to be numbered. Since compiled BASIC
only requires statement numbers for transfer purposes, the
program can be modified to fit within compiler limitations
by removing unnecessary statement numbers.
An additional benefit of removal of unneeded statement numbers
is that the compiler can then produce a more efficient code.
We therefore have two very good reasons for doing this - the
question is how?
Once we remove any statement number from a line of coding we
will no longer be able to read the program as a BASIC program
file. However, if we save the interpreter BASIC program in
ASCII format we will be able to modify the program using
the Line Editor (EDLIN) under DOS. And if you refer to the
statement number references listing you will see that any
statement in the listing that does not have any references
shown next to it can be removed as a statement number.
The enhanced version of our cross reference utility has
the capability to take a BASIC source program file and the
corresponding cross reference file, and to automatically
generate a new source program file that has all the
unreferenced statement numbers removed. The enhanced
version is described at the end of this documentation, and
we invite you to give it a try.
Until you do, we offer the following method to accomplish
this. It probably seems tedious, and it is, but remember you
only have to do this once for a program and you're finished.
So here goes...
1. Load the BASIC program into memory with the BASIC
interpreter and save the program on disk (as you have to
do to run the Cross Reference Utility) with the command:
SAVE "FILENAME",A .
2. Run the Cross Reference Utility for the BASIC program saved
above, and obtain a printout of the statement number
references.
3. List the BASIC program with the Cross Reference Utility
using the /N control parameter. This will list the
line number for each BASIC statement in the program.
23
4. Load the program into memory under DOS using EDLIN. (See
the DOS manual for complete information on using EDLIN).
This can be accomplished by the command
EDLIN filespec .
5. Each statement in the statement number reference listing
that does not have a reference shown can have its statement
number removed. The program listing will give the line
number corresponding to the EDLIN line number for each
statement. These two documents can be used in combination
to accomplish the statement number removal, as follows.
6. For illustrative purposes, we'll use the sample program
TESTPROG.BAS on this disk. Use the cross reference
utility to get the listings you need.
7. The first statement number that can be removed is statement
number 10, which has no references listed. From the program
listing, this statement is line number 1.
8. EDLIN displays the prompt * . Type the number 1 ,
following the asterisk, for line number 1, and press the
enter key.
9. EDLIN will display the prompt and line number followed by
contents of that line. Under it will be the prompt and
line number repeated with the rest of the line blank.
10. Press the space bar twice. This will blank out the statement
number in the replacement line.
11. Press the F3 key. This will duplicate the rest of the line.
The new line should be identical to the original line except
that the statement number will have been blanked out.
12. Press the enter key. The line will be changed in memory, and
EDLIN will return to the asterisk prompt.
13. Repeat steps 8 through 12 for each additional statement
number to be deleted. For the sample program, statement
numbers 20 through 50, 70 through 140, and 170, corresponding
to line numbers 2 through 5, 8 through 15, and 18,
respectively, remain to be processed.
14. When all changes have been made, follow the asterisk prompt
with the letter E and press the enter key.
15. When EDLIN is finished updating the files, the original file
will be renamed with an extension of .BAK and the new
file will have the filename and extension that was specified
in the EDLIN command.
16. This new file may now be used as input to the BASIC compiler
and to the Cross Reference Utility, in both cases with a
/N parameter.
17. Subsequent changes to this new file will have to be made
using EDLIN since the BASIC interpreter will no longer accept
the program with missing statement numbers.
24
18. One final fly in the ointment. Your BASIC source program
may be too large for EDLIN to load into memory completely.
If the file is loaded completely, EDLIN will display the
message
End of input file
*_
If only the asterisk prompt appears, the file has not been
fully loaded. In that case, eventually when you enter a
line number nothing will happen, and EDLIN will simply
repeat the asterisk prompt on the next line. At this point
you are past the end of the file in memory. Not to worry...
19. Follow the asterisk prompt with the letter W and press
the enter key. This will write the changed file onto disk.
20. Follow the next asterisk prompt with the letter A and
press the enter key. This will append more of the file into
memory. You will then be able to continue as before, with
one adjustment.
21. The line numbers for the statements in memory will, for the
moment, no longer correspond to what you have in the program
listing. This is because the first line in memory is now
a program statement from somewhere in the middle of your
program. Once more, not to worry...
22. Follow the asterisk prompt with the numeral 1 and press
the enter key. Line 1 will now be displayed. (Pressing
the enter key at this point will get you back to the asterisk
prompt without making a change in line 1).
23. Now find the BASIC program statement in your program listing
corresponding to the statement shown in line 1. This will
provide you with the offset from the statement numbers in
your listing, and the requested line number can be adjusted
accordingly.
24. Assume, for example, that line number 1 shown by EDLIN is
line number 855 in your program listing. Then to find a
line number XXX in your program listing, subtract 854
(855-1) from XXX and use the result as the line number
requested of EDLIN.
25. In the example above, program listing line number 855 would
be requested as line number 855-854 = 1 to EDLIN, program
listing line number 1000 would be requested as line number
1000-854 = 146 to EDLIN, etc.
26. Steps 19 through 25 may have to be repeated in the unlikely
event that the complete program was still not processed.
The procedure is complete when EDLIN displays the
End of input file message.
27. At the completion of these changes, follow the asterisk
prompt with the letter E and press the enter key to
update the file, as mentioned above.
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If all this seems tedious, remember...
1. You only have to do this once for a particular program.
2. You don't have to do the whole thing at one sitting.
You can do part of it with EDLIN, end the session with
the *E entry, and continue at another time.
3. Once you get the knack of it, it will proceed very fast
since the actual procedure is quite simple.
4. It will be well worth the effort in terms of what you
will be able to accomplish with the BASIC compiler.
5. You can eliminate all the tedium by purchasing the
enhanced version of our cross reference utility.
SOME FINAL WORDS
Although some people might argue otherwise, nobody's perfect.
We've tested our Cross Reference Utility thoroughly and there
are no bugs that we know about. But things being what they
are, there undoubtedly will be bugs showing up as the program
finds more and more use. We`d appreciate it if you would let
us know if you encounter any problems with the program. We
promise to consider all correspondence and we'll do our best
to fix any bugs that may occur.
Along the same tack, we'd appreciate any comments you have
regarding changes, improvements, enhancements, etc. that you
would like to see in the program. Again, we'll give thorough
consideration to all suggestions, and we'll try to incorporate
those that appear to be of most potential interest.
ENHANCED CROSS REFERENCE UTILITY
We invite you to try our enhanced Cross Reference Utility.
Following are the features that will probably be of greatest
interest.
1. The enhanced version produces a cross reference for
compiled BASIC programs in terms of line numbers,
rather than statement numbers. This is of particular
benefit in typical compiled programs that have mostly
un-numbered statements. If you run a cross reference
for a compiled program with this version of BASICREF,
you will see many references to the same statement
number for blocks of coding, if the program does not
have many statement numbers. In the enhanced version,
each line will have a unique reference. The difference
is appreciable, making it much easier to locate items
in a listing produced by the enhanced version.
2. The enhanced version has a routine to automatically
remove unreferenced statement numbers from a BASIC
program, to increase the benefit from compiled BASIC
programs as discussed earlier.
26
3. The enhanced version of BASICREF can automatically
remove REM statements from a source program. This will
free additional memory in interpreter BASIC programs where
program size is straining available memory.
4. The enhanced version of BASICREF provides a simplified
procedure for unprotecting interpreter BASIC programs
that have been saved to disk with the P option.
If you find this version of the Cross Reference Utility useful
we think you will find the enhanced version of the program
even more useful. You can order the enhanced version for
twenty five dollars (thirty five if you haven't sent the ten
dollar contribution for the standard version), and for your
money you will get ...
1. A disk containing the enhanced program.
2. Free updates, corrections, modifications, etc. to
the program any time after purchase. (You'll just
have to supply a blank disk, mailer and postage).
3. Free consultation by mail or phone on any aspect
of the program.
An order form appears on page 29 for your convenience.
*** And as a special bonus, so that you won't have to pay
for BASICREF twice, if you purchased this standard version
from any of the several user groups and other sources (as
opposed to obtaining a copy free from a friend) you can
deduct five dollars from the price of the enhanced version.
See the order form for details. ***
27
DISCLAIMER
This program is provided "as is" without warranty of any kind,
either express or implied, including, but not limited to, the
implied warranties of merchantability and fitness for a
particular purpose. In no event will the Author be liable for
any damages, including any lost profits, lost savings or other
incidental or consequential damages arising out of the use or
inability to use this program, even if the Author has been
advised of such damages, or for any claim by any other party.
Despite this necessary legality, it should be obvious by now
that we have corrected bugs in the program, and we assure you
that we will continue to do so. Just let us know of any you
find and we will do our best to maintain the program in an
error-free condition.
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PROGRAM ORDER/CONTRIBUTION/INFORMATION FORM
To: Excelsior Software, Inc.
P. O. Box 226
New Milford, NJ 07646
Please send a copy of the enhanced version of the BASIC Cross
Reference Utility. I understand that this version of BASICREF
is copyrighted, and I agree not to distribute any unauthorized
copies of the enhanced version.
___ BASIC Cross Reference Utility - @ $25.00 ______
Enhanced Version
___ Contribution for the standard - $10.00 ______
version of BASICREF if not
previously submitted.
Subtotal ______
___ I obtained the standard version
of BASICREF from the following paid
source: ______________________________
I am deducting $5.00 from the purchase price ______
Total Enclosed ______
Ship To: __________________________________________
__________________________________________
__________________________________________
__________________________________________
Please pay by check or money order. For orders to New Jersey
please add 6% sales tax. BASICREF requires DOS 2.0 or later.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
_____ I'm not ready to order the enhanced version just now,
but I do want to further the "User Supported" concept. Enclosed
find a contribution of ten dollars in support of the standard
version of BASICREF. I understand you will keep me informed of
any corrections you make to the standard version of the program.
_____ I would be interested in a version of BASICREF for the
Microsoft QuickBASIC compiler. Please let me know when you have
a version available. I understand that this does not obligate
me in any way.
Name & address: _________________________________________
_________________________________________
_________________________________________
_________________________________________
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