RENAME - Variable renamer for BASIC
Kelvin Smith, Financial Computer Systems, Inc.
When I joined this company, I found many of the
programs had been written in a dialect of Basic which
allowed only one-letter or one-letter
plus
one-digit
variable
names, a horror story only too familiar to
old-timers in the Basic world. Giving the variables more
meaningful names was a top priority in order to be able to
maintain and enhance the programs.
However, finding and
changing single-character names is a tedious process very
prone to error;
since one program alone (in several
subprograms, but with common variable names) ran to over 120
pages of code, I was very uncomfortable with the idea of
making the changes manually.
Being an old TECO hacker ("hacker" used in the positive
sense), it occurred to me that the problem might be amenable
to a TECO solution. The program which follows will properly
distinguish even single-character variable names and rename
them to whatever you desire.
While this program was
designed
to
work
with
BASIC-PLUS-2 programs, using TECO V40 for RSTS/E, it should
work properly for most BASIC and TECO combination on PDP-11s
and VAXes. It may be usable in other language environments
as well, but obviously the tightness of fit will depend on
the
particular
language's syntax.
RENAME depends on
punctuation to separate the symbols it looks at:
quoted
strings (with either single or double quotation marks) are
skipped; exclamation points mark the beginning and end of
comments (by default, nothing in comments is changed);
dollar and percent signs indicate a string or integer
suffix;
an open parenthesis marks an array (or function)
reference; underscores are acceptable in the middle of a
variable name;
all other punctuation is considered a
breakpoint. Note that this means that legal "no extend"
Basic-Plus code, which did not require spaces to separate
variables and keywords, will not be processed correctly.
Fixing that code is quite another matter.
Since I was not inclined to completely emulate the
syntax checking done by the BASIC compiler, this program
does have a few restrictions.
It works by essentially
breaking out every different symbol reference, whether a
variable name or a valid BASIC construct. (A statement like
PRINT, a built-in function like EDIT$, or a variable like
FOO% will each get picked out.) It then checks to see if the
symbol found is in its list of variables to change; a match
generates a replacement.
This means that RENAME
can
annihilate the meaning of a program (try changing IF to LET,
for example); however, this could also
changing "declining features" like CVT$$().
be
useful
for
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Additional restrictions:
1) While RENAME's input routine kicks out gross errors
in variable names, there is nonetheless a large class of
character sequences which will pass RENAME but bomb on a
compile attempt. If you find, however, that you have given
an illegal name, you can simply change that again.
2) A few BASIC statements refer to arrays without using
parentheses.
RENAME handles the CHANGE statement correctly
as long as the string variable has a "$" suffix.
It does
not handle MAT, essentially because I don't use those
functions. You can always add your own code.
3) Similarly, RENAME
will
not
change
function
references inside a multi-line DEF, where the function name
is referred to without parentheses. The workaround for this
is to enter two renaming lines, one with and one without the
terminating parenthesis:
e.g.,
FNA%(/FNNEW.NAME%(
and
FNA%/FNNEW.NAME%.
A performance note: Since each symbol is chopped out
and checked, it is much better from a performance standpoint
to run RENAME once with a long list of variables to change
than to run it several times with short lists. Like any
TECO program, RENAME is a system hog while running (and on
long programs may take 5 minutes or more of CPU time); you
may want to run it in batch mode at reduced priority.
Instructions for use
RENAME can be RUN like any other program; you need not
enter TECO first, and the user need not even know that the
program is written in TECO. (Note: This may be different
on non-RSTS systems.) It is highly recommended that RENAME
be SQUished (using the SQU macro available
on
some
distribution tapes from DEC) before running, since the
comments slow down execution enormously.
When run, RENAME responds with its header and
prompts:
File to fix <.B2S>?
Enter the name of the program to modify;
the default
filetype is .B2S. The file will be opened in backup mode;
when complete, RSTS gives the old version of the file the
filetype .BAK.
(Other systems may handle backup mode
differently; see the TECO User's Guide for details.) It is
recommended that you NOT specify /B2, if you still use
ampersand continuation, since RENAME gets just one line at a
time, and thus would eliminate all the ampersands. (If you
wish to switch from ampersands and backslashes to the BASIC
Version 2 format, with implicit statement continuation, see
•RENAME - Variable renamer
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my STRIP macro elsewhere on this tape.)
If you want RENAME to change any matches in comments,
add /C to the file name.
Note that this will slow
execution.
Enter old and new variable name, separated by "/".
Enter "@filnam" to use list of names in a file.
Press <CR> to end list.
Old name/new name?
Enter one by one your list of variables to rename with
their new names. The format of input is "OLDNAME/NEWNAME".
Any $ or % suffix must be included. If the variable is an
array (of any number of dimensions), it must be followed by
an open parenthesis "(". Several examples are shown at the
end of this documentation.
You can put a list of variable names in another file
and read those in by entering "@filnam" (e.g., "@FOO.LST").
(This is particularly useful for a number of subprograms
with common variable names.) RENAME will do the same error
checking that it does on normal input, listing out each line
as it reads and processes that line.
After RENAME is
finished with the file, it will return to the "Old name/new
name" prompt.
If you want RENAME to assume that all renamings are
correct which would normally require confirmation (see
below), add /N to the indirect file name ("No confirm").
Note that any illegal input is still rejected.
When all names have been entered, press <CR>
response to the prompt and the changing will begin.
in
Typing CTRL/C at any time during the operation will
cause an abort with the original file left intact. When
finished, RENAME will print out the total number
of
references changed and exit.
Error checking
RENAME does a limited amount of checking the input.
The following errors cause the input line to be rejected:
1)
2)
3)
Only one name has a "(" indicating an array.
One of the names does not begin with a letter.
The "old" name has already been used.
4)
5)
No "/" is found separating the two names.
One of the names ends with "$" and the other ends
with "%".
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The following situations cause RENAME to ask for
confirmation of the validity of the input, unless the /N
qualifier was used when the file name holding a variable
list was entered (see above):
1) One name has a $ or %, but the other does not (this
may be correct when changing from floating point variables
to integers or when changing implicitly defined variables to
DECLAREd variables).
2) The "new" name has already been used (you may want
to combine two old variables into one new one, particularly
a dummy).
Input examples
A%/FOO%
A%(/SORT%(
Q0/TEST.VAR%
FIRST.VAR$/SECOND.VAR
T%/R$
Q0/NEW.TEST%
B%/FOO%
A normal change.
An array change.
Confirm: is the "%" correct?
Confirm: is the "$" correct?
Illegal: "%" and "$" conflict.
Illegal: Q0 was already used.
Same new name as A% above; confirm
if this is correct.
As always with TECO, experimentation is encouraged. If
you
have
any questions, or come up with ideas for
enhancements, feel free to contact me.
Kelvin Smith
Financial Computer Systems, Inc.
1 Strawberry Hill Ct.
Stamford, CT 06902
(203) 357-0504