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 }