Q61336: Explanation of Compiler Workspace and What Affects It

Article: Q61336
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S900415-7 B_BasicCom | mspl13_basic
Last Modified: 15-JAN-1991

The information below shows what items affect compiler workspace, and
some practices that can be used when compiler workspace must be
increased.

The compiler workspace is displayed by the "Bytes Available" and
"Bytes Free" lines given at the end of compilation. For more
information on these lines, query on the following words:

   BASIC and bytes available and free and symbol table and workspace

This information applies to Microsoft QuickBASIC versions 4.00, 4.00b,
and 4.50 for MS-DOS; to Microsoft BASIC Compiler versions 6.00 and
6.00b for MS-DOS and MS OS/2; and to Microsoft BASIC Professional
Development System (PDS) versions 7.00 and 7.10 for MS-DOS and MS
OS/2.

The compiler workspace is made up of the line-number table, symbol
table, and working storage for compiler code generation and
optimization. Because of this, the compiler workspace is affected by
such things as the length of variable, procedure, and line label
names, and the number of lines in the program. The following
paragraphs detail some of the things that affect the compiler
workspace:

   Variable SUB,    Because variables go into the symbol table, they
   and FUNCTION     have a direct effect on compiler workspace.
   names
                    Each new variable has some initial overhead plus
                    additional overhead for each character in the
                    variable name. Once a variable is defined, it
                    has no extra effect on the compiler workspace no
                    matter how many times it is used again.

   Line numbers     Every line number decreases the compiler
                    workspace. Unlike variable and procedure names,
                    however, it does not matter how big a line
                    number is. The line number 10 takes just as
                    much compiler workspace as does the line number
                    10,000.

   Program lines    Each line in the program takes up some compiler
                    workspace. Two PRINT statements put on the same
                    line, such as

                       PRINT : PRINT

                    take up less compiler workspace than when the
                    statements are put on two separate lines, as in:

                       PRINT
                       PRINT

                    Extra blank lines between code have no effect on
                    compiler workspace. Therefore, the following
                    three lines of code take just as much compiler
                    workspace as do the previous two lines of code:

                       PRINT

                       PRINT

If a program is running out of compiler workspace (bytes available
goes to zero), you can try each of the following to increase the
workspace:

1. Break the code into multiple modules. This is the best solution
   from a structured programming point of view. Each module has the
   full compiler workspace available to it, and because code is taken
   out of the original program, compiler workspace will be used
   regained.

2. Put multiple statements on each line. Although not recommended for
   structured programming, moving multiple source lines onto a single
   line separated by a colon (:) will decrease the amount of compiler
   workspace being used.

3. Decrease the size of SUB, FUNCTION, and variable names. This will
   make the code less readable, but again can be used when compiler
   workspace is at a premium.

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