Minix1.5/commands/m4/main.c
/*
* main.c
* Facility: m4 macro processor
* by: oz
*/
#include "mdef.h"
/*
* 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.
*
* 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
*
* Modification History:
*
* Jan 28 1986 Oz Break the whole thing into little
* pieces, for easier (?) maintenance.
*
* Dec 12 1985 Oz Optimize the code, try to squeeze
* few microseconds out..
*
* Dec 05 1985 Oz Add getopt interface, define (-D),
* undefine (-U) options.
*
* Oct 21 1985 Oz Clean up various bugs, add comment handling.
*
* June 7 1985 Oz Add some of SysV m4 stuff (m4wrap, pushdef,
* popdef, decr, shift etc.).
*
* June 5 1985 Oz Initial cut.
*
* 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 nonsense 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
* . |
* +-------+ |
* | <----------+
* +-------+
*
* [2] We have three types of null values:
*
* nil - nodeblock pointer type 0
* null - null string ("")
* NULL - Stdio-defined NULL
*
*/
ndptr hashtab[HASHSIZE]; /* hash table for macros etc. */
char buf[BUFSIZE]; /* push-back buffer */
char *bp = buf; /* first available character */
char *endpbb = buf+BUFSIZE; /* end of push-back buffer */
stae mstack[STACKMAX+1]; /* stack of m4 machine */
char strspace[STRSPMAX+1]; /* string space for evaluation */
char *ep = strspace; /* first free char in strspace */
char *endest= strspace+STRSPMAX;/* end of string space */
int sp; /* current m4 stack pointer */
int fp; /* m4 call frame pointer */
FILE *infile[MAXINP]; /* input file stack (0=stdin) */
FILE *outfile[MAXOUT]; /* diversion array(0=bitbucket)*/
FILE *active; /* active output file pointer */
char *m4temp; /* filename for diversions */
int ilevel = 0; /* input file stack pointer */
int oindex = 0; /* diversion index.. */
char *null = ""; /* as it says.. just a null.. */
char *m4wraps = ""; /* m4wrap string default.. */
char lquote = LQUOTE; /* left quote character (`) */
char rquote = RQUOTE; /* right quote character (') */
char scommt = SCOMMT; /* start character for comment */
char ecommt = ECOMMT; /* end character for comment */
struct keyblk keywrds[] = { /* m4 keywords to be installed */
"include", INCLTYPE,
"sinclude", SINCTYPE,
"define", DEFITYPE,
"defn", DEFNTYPE,
"divert", DIVRTYPE,
"expr", EXPRTYPE,
"eval", EXPRTYPE,
"substr", SUBSTYPE,
"ifelse", IFELTYPE,
"ifdef", IFDFTYPE,
"len", LENGTYPE,
"incr", INCRTYPE,
"decr", DECRTYPE,
"dnl", DNLNTYPE,
"changequote", CHNQTYPE,
"changecom", CHNCTYPE,
"index", INDXTYPE,
#ifdef EXTENDED
"paste", PASTTYPE,
"spaste", SPASTYPE,
#endif
"popdef", POPDTYPE,
"pushdef", PUSDTYPE,
"dumpdef", DUMPTYPE,
"shift", SHIFTYPE,
"translit", TRNLTYPE,
"undefine", UNDFTYPE,
"undivert", UNDVTYPE,
"divnum", DIVNTYPE,
"maketemp", MKTMTYPE,
"errprint", ERRPTYPE,
"m4wrap", M4WRTYPE,
"m4exit", EXITTYPE,
#if unix || vms
"syscmd", SYSCTYPE,
"sysval", SYSVTYPE,
#endif
#if unix
"unix", MACRTYPE,
#else
#if vms
"vms", MACRTYPE,
#endif
#endif
};
#define MAXKEYS (sizeof(keywrds)/sizeof(struct keyblk))
extern ndptr lookup();
extern ndptr addent();
extern int onintr();
extern char *malloc();
extern char *mktemp();
extern int optind;
extern char *optarg;
main(argc,argv)
char *argv[];
{
register int c;
register int n;
char *p;
if (signal(SIGINT, SIG_IGN) != SIG_IGN)
signal(SIGINT, onintr);
#ifdef NONZEROPAGES
initm4();
#endif
initkwds();
while ((c = getopt(argc, argv, "tD:U:o:")) != EOF)
switch(c) {
case 'D': /* define something..*/
for (p = optarg; *p; p++)
if (*p == '=')
break;
if (*p)
*p++ = EOS;
dodefine(optarg, p);
break;
case 'U': /* undefine... */
remhash(optarg, TOP);
break;
case 'o': /* specific output */
case '?':
default:
usage();
}
infile[0] = stdin; /* default input (naturally) */
active = stdout; /* default active output */
m4temp = mktemp(DIVNAM); /* filename for diversions */
sp = -1; /* stack pointer initialized */
fp = 0; /* frame pointer initialized */
macro(); /* get some work done here */
if (*m4wraps) { /* anything for rundown ?? */
ilevel = 0; /* in case m4wrap includes.. */
putback(EOF); /* eof is a must !! */
pbstr(m4wraps); /* user-defined wrapup act */
macro(); /* last will and testament */
}
else /* default wrap-up: undivert */
for (n = 1; n < MAXOUT; n++)
if (outfile[n] != NULL)
getdiv(n);
/* remove bitbucket if used */
if (outfile[0] != NULL) {
(void) fclose(outfile[0]);
m4temp[UNIQUE] = '0';
#if vms
(void) remove(m4temp);
#else
(void) unlink(m4temp);
#endif
}
exit(0);
}
ndptr inspect(); /* forward ... */
/*
* macro - the work horse..
*
*/
macro() {
char token[MAXTOK];
register char *s;
register int t, l;
register ndptr p;
register int nlpar;
cycle {
if ((t = gpbc()) == '_' || isalpha(t)) {
putback(t);
if ((p = inspect(s = token)) == nil) {
if (sp < 0)
while (*s)
putc(*s++, active);
else
while (*s)
chrsave(*s++);
}
else {
/*
* real thing.. First build a call frame:
*
*/
pushf(fp); /* previous call frm */
pushf(p->type); /* type of the call */
pushf(0); /* parenthesis level */
fp = sp; /* new frame pointer */
/*
* now push the string arguments:
*
*/
pushs(p->defn); /* defn string */
pushs(p->name); /* macro name */
pushs(ep); /* start next..*/
putback(l = gpbc());
if (l != LPAREN) { /* add bracks */
putback(RPAREN);
putback(LPAREN);
}
}
}
else if (t == EOF) {
if (sp > -1)
error("m4: unexpected end of input");
if (--ilevel < 0)
break; /* all done thanks.. */
(void) fclose(infile[ilevel+1]);
continue;
}
/*
* non-alpha single-char token seen..
* [the order of else if .. stmts is
* important.]
*
*/
else if (t == lquote) { /* strip quotes */
nlpar = 1;
do {
if ((l = gpbc()) == rquote)
nlpar--;
else if (l == lquote)
nlpar++;
else if (l == EOF)
error("m4: missing right quote");
if (nlpar > 0) {
if (sp < 0)
putc(l, active);
else
chrsave(l);
}
}
while (nlpar != 0);
}
else if (sp < 0) { /* not in a macro at all */
if (t == scommt) { /* comment handling here */
putc(t, active);
while ((t = gpbc()) != ecommt)
putc(t, active);
}
putc(t, active); /* output directly.. */
}
else switch(t) {
case LPAREN:
if (PARLEV > 0)
chrsave(t);
while (isspace(l = gpbc()))
; /* skip blank, tab, nl.. */
putback(l);
PARLEV++;
break;
case RPAREN:
if (--PARLEV > 0)
chrsave(t);
else { /* end of argument list */
chrsave(EOS);
if (sp == STACKMAX)
error("m4: internal stack overflow");
if (CALTYP == MACRTYPE)
expand(mstack+fp+1, sp-fp);
else
eval(mstack+fp+1, sp-fp, CALTYP);
ep = PREVEP; /* flush strspace */
sp = PREVSP; /* previous sp.. */
fp = PREVFP; /* rewind stack...*/
}
break;
case COMMA:
if (PARLEV == 1) {
chrsave(EOS); /* new argument */
while (isspace(l = gpbc()))
;
putback(l);
pushs(ep);
}
break;
default:
chrsave(t); /* stack the char */
break;
}
}
}
/*
* build an input token..
* consider only those starting with _ or A-Za-z. This is a
* combo with lookup to speed things up.
*/
ndptr
inspect(tp)
register char *tp;
{
register int h = 0;
register char c;
register char *name = tp;
register char *etp = tp+MAXTOK;
register ndptr p;
while (tp < etp && (isalnum(c = gpbc()) || c == '_'))
h += (*tp++ = c);
putback(c);
if (tp == etp)
error("m4: token too long");
*tp = EOS;
for (p = hashtab[h%HASHSIZE]; p != nil; p = p->nxtptr)
if (strcmp(name, p->name) == 0)
break;
return(p);
}
#ifdef NONZEROPAGES
/*
* initm4 - initialize various tables. Useful only if your system
* does not know anything about demand-zero pages.
*
*/
initm4()
{
register int i;
for (i = 0; i < HASHSIZE; i++)
hashtab[i] = nil;
for (i = 0; i < MAXOUT; i++)
outfile[i] = NULL;
}
#endif
/*
* initkwds - initialise m4 keywords as fast as possible.
* This very similar to install, but without certain overheads,
* such as calling lookup. Malloc is not used for storing the
* keyword strings, since we simply use the static pointers
* within keywrds block. We also assume that there is enough memory
* to at least install the keywords (i.e. malloc won't fail).
*
*/
initkwds() {
register int i;
register int h;
register ndptr p;
for (i = 0; i < MAXKEYS; i++) {
h = hash(keywrds[i].knam);
p = (ndptr) malloc(sizeof(struct ndblock));
p->nxtptr = hashtab[h];
hashtab[h] = p;
p->name = keywrds[i].knam;
p->defn = null;
p->type = keywrds[i].ktyp | STATIC;
}
}