64 lines
2 KiB
Text
64 lines
2 KiB
Text
m4 - macro processor
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PD m4 is based on the macro tool distributed with the software
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tools (VOS) package, and described in the "SOFTWARE TOOLS" and
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"SOFTWARE TOOLS IN PASCAL" books. It has been expanded to include
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most of the command set of SysV m4, the standard UN*X macro processor.
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Since both PD m4 and UN*X m4 are based on SOFTWARE TOOLS macro,
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there may be certain implementation similarities between
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the two. The PD m4 was produced without ANY references to m4
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sources.
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written by: Ozan S. Yigit
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References:
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Software Tools distribution: macro
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Kernighan, Brian W. and P. J. Plauger, SOFTWARE
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TOOLS IN PASCAL, Addison-Wesley, Mass. 1981
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Kernighan, Brian W. and P. J. Plauger, SOFTWARE
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TOOLS, Addison-Wesley, Mass. 1976
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Kernighan, Brian W. and Dennis M. Ritchie,
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THE M4 MACRO PROCESSOR, Unix Programmer's Manual,
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Seventh Edition, Vol. 2, Bell Telephone Labs, 1979
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System V man page for M4
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Implementation Notes:
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[1] PD m4 uses a different (and simpler) stack mechanism than the one
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described in Software Tools and Software Tools in Pascal books.
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The triple stack thing is replaced with a single stack containing
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the call frames and the arguments. Each frame is back-linked to a
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previous stack frame, which enables us to rewind the stack after
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each nested call is completed. Each argument is a character pointer
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to the beginning of the argument string within the string space.
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The only exceptions to this are (*) arg 0 and arg 1, which are
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the macro definition and macro name strings, stored dynamically
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for the hash table.
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. .
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| . | <-- sp | . |
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+-------+ +-----+
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| arg 3 ------------------------------->| str |
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+-------+ | . |
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| arg 2 --------------+ .
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+-------+ |
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* | | |
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+-------+ | +-----+
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| plev | <-- fp +---------------->| str |
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+-------+ | . |
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| type | .
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+-------+
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| prcf -----------+ plev: paren level
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+-------+ | type: call type
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| . | | prcf: prev. call frame
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. |
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+-------+ |
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| <----------+
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+-------+
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