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#include <stdio.h>
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#include <stdlib.h>
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#include "grap.h"
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#include "y.tab.h"
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typedef struct {
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	Obj	*var;	/* index variable */
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	double	to;	/* limit */
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	double	by;
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	int	op;	/* operator */
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	char	*str;	/* string to push back */
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} For;
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#define	MAXFOR	10
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For	forstk[MAXFOR];	/* stack of for loops */
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For	*forp = forstk;	/* pointer to current top */
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void forloop(Obj *var, double from, double to, int op, double by, char *str)	/* set up a for loop */
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{
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	fprintf(tfd, "# for %s from %g to %g by %c %g \n",
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		var->name, from, to, op, by);
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	if (++forp >= forstk+MAXFOR)
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		ERROR "for loop nested too deep" FATAL;
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	forp->var = var;
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	forp->to = to;
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	forp->op = op;
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	forp->by = by;
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	forp->str = str;
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	setvar(var, from);
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	nextfor();
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	unput('\n');
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}
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void nextfor(void)	/* do one iteration of a for loop */
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{
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	/* BUG:  this should depend on op and direction */
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	if (forp->var->fval > SLOP * forp->to) {	/* loop is done */
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		free(forp->str);
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		if (--forp < forstk)
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			ERROR "forstk popped too far" FATAL;
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	} else {		/* another iteration */
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		pushsrc(String, "\nEndfor\n");
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		pushsrc(String, forp->str);
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	}
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}
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void endfor(void)	/* end one iteration of for loop */
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{
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	switch (forp->op) {
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	case '+':
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	case ' ':
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		forp->var->fval += forp->by;
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		break;
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	case '-':
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		forp->var->fval -= forp->by;
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		break;
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	case '*':
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		forp->var->fval *= forp->by;
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		break;
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	case '/':
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		forp->var->fval /= forp->by;
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		break;
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	}
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	nextfor();
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}
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char *ifstat(double expr, char *thenpart, char *elsepart)
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{
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	dprintf("if %g then <%s> else <%s>\n", expr, thenpart, elsepart? elsepart : "");
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	if (expr) {
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		unput('\n');
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		pushsrc(Free, thenpart);
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		pushsrc(String, thenpart);
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		unput('\n');
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  		if (elsepart)
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			free(elsepart);
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		return thenpart;	/* to be freed later */
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	} else {
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		free(thenpart);
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		if (elsepart) {
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			unput('\n');
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			pushsrc(Free, elsepart);
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			pushsrc(String, elsepart);
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			unput('\n');
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		}
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		return elsepart;
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	}
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}