From 5d69c6a2661bba0a22f3ecfd517e2e9767a38346 Mon Sep 17 00:00:00 2001 From: Cem Keylan Date: Fri, 16 Oct 2020 17:47:01 +0300 Subject: add tools --- usr.bin/m4/NOTES | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 usr.bin/m4/NOTES (limited to 'usr.bin/m4/NOTES') diff --git a/usr.bin/m4/NOTES b/usr.bin/m4/NOTES new file mode 100644 index 0000000..d60f80e --- /dev/null +++ b/usr.bin/m4/NOTES @@ -0,0 +1,64 @@ +m4 - macro processor + +PD m4 is based on the macro tool distributed with the software +tools (VOS) package, and described in the "SOFTWARE TOOLS" and +"SOFTWARE TOOLS IN PASCAL" books. It has been expanded to include +most of the command set of SysV m4, the standard UN*X macro processor. + +Since both PD m4 and UN*X m4 are based on SOFTWARE TOOLS macro, +there may be certain implementation similarities between +the two. The PD m4 was produced without ANY references to m4 +sources. + +written by: Ozan S. Yigit + +References: + + Software Tools distribution: macro + + Kernighan, Brian W. and P. J. Plauger, SOFTWARE + TOOLS IN PASCAL, Addison-Wesley, Mass. 1981 + + Kernighan, Brian W. and P. J. Plauger, SOFTWARE + TOOLS, Addison-Wesley, Mass. 1976 + + Kernighan, Brian W. and Dennis M. Ritchie, + THE M4 MACRO PROCESSOR, Unix Programmer's Manual, + Seventh Edition, Vol. 2, Bell Telephone Labs, 1979 + + System V man page for M4 + + +Implementation Notes: + +[1] PD m4 uses a different (and simpler) stack mechanism than the one + described in Software Tools and Software Tools in Pascal books. + The triple stack thing is replaced with a single stack containing + the call frames and the arguments. Each frame is back-linked to a + previous stack frame, which enables us to rewind the stack after + each nested call is completed. Each argument is a character pointer + to the beginning of the argument string within the string space. + The only exceptions to this are (*) arg 0 and arg 1, which are + the macro definition and macro name strings, stored dynamically + for the hash table. + + . . + | . | <-- sp | . | + +-------+ +-----+ + | arg 3 ------------------------------->| str | + +-------+ | . | + | arg 2 --------------+ . + +-------+ | + * | | | + +-------+ | +-----+ + | plev | <-- fp +---------------->| str | + +-------+ | . | + | type | . + +-------+ + | prcf -----------+ plev: paren level + +-------+ | type: call type + | . | | prcf: prev. call frame + . | + +-------+ | + | <----------+ + +-------+ -- cgit v1.2.3