plan9port

fork of plan9port with libvec, libstr and libsdb
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for.c (1890B)

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