plan9port

fork of plan9port with libvec, libstr and libsdb
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for.c (1877B)

      1 #include <stdio.h>
      2 #include "pic.h"
      3 #include "y.tab.h"
      4 
      5 #define	SLOP	1.001
      6 
      7 typedef struct {
      8 	char	*var;	/* index variable */
      9 	double	to;	/* limit */
     10 	double	by;
     11 	int	op;	/* operator */
     12 	char	*str;	/* string to push back */
     13 } For;
     14 
     15 For	forstk[10];	/* stack of for loops */
     16 For	*forp = forstk;	/* pointer to current top */
     17 
     18 void
     19 forloop(char *var, double from, double to, int op, double by, char *str)	/* set up a for loop */
     20 {
     21 	dprintf("# for %s from %g to %g by %c %g \n",
     22 		var, from, to, op, by);
     23 	if (++forp >= forstk+10)
     24 		ERROR "for loop nested too deep" FATAL;
     25 	forp->var = var;
     26 	forp->to = to;
     27 	forp->op = op;
     28 	forp->by = by;
     29 	forp->str = str;
     30 	setfval(var, from);
     31 	nextfor();
     32 	unput('\n');
     33 }
     34 
     35 void
     36 nextfor(void)	/* do one iteration of a for loop */
     37 {
     38 	/* BUG:  this should depend on op and direction */
     39 	if (getfval(forp->var) > SLOP * forp->to) {	/* loop is done */
     40 		free(forp->str);
     41 		if (--forp < forstk)
     42 			ERROR "forstk popped too far" FATAL;
     43 	} else {		/* another iteration */
     44 		pushsrc(String, "\nEndfor\n");
     45 		pushsrc(String, forp->str);
     46 	}
     47 }
     48 
     49 void
     50 endfor(void)	/* end one iteration of for loop */
     51 {
     52 	struct symtab *p = lookup(forp->var);
     53 
     54 	switch (forp->op) {
     55 	case '+':
     56 	case ' ':
     57 		p->s_val.f += forp->by;
     58 		break;
     59 	case '-':
     60 		p->s_val.f -= forp->by;
     61 		break;
     62 	case '*':
     63 		p->s_val.f *= forp->by;
     64 		break;
     65 	case '/':
     66 		p->s_val.f /= forp->by;
     67 		break;
     68 	}
     69 	nextfor();
     70 }
     71 
     72 char*
     73 ifstat(double expr, char *thenpart, char *elsepart)
     74 {
     75 	dprintf("if %g then <%s> else <%s>\n", expr, thenpart, elsepart? elsepart : "");
     76 	if (expr) {
     77 		unput('\n');
     78 		pushsrc(Free, thenpart);
     79 		pushsrc(String, thenpart);
     80 		unput('\n');
     81   		if (elsepart)
     82 			free(elsepart);
     83 		return thenpart;	/* to be freed later */
     84 	} else {
     85 		free(thenpart);
     86 		if (elsepart) {
     87 			unput('\n');
     88 			pushsrc(Free, elsepart);
     89 			pushsrc(String, elsepart);
     90 			unput('\n');
     91 		}
     92 		return elsepart;
     93 	}
     94 }