Subversion Repositories planix.SVN

#include <stdio.h>
#include <stdlib.h>
#include "grap.h"
#include "y.tab.h"

typedef struct {
        Obj     *var;   /* index variable */
        double  to;     /* limit */
        double  by;
        int     op;     /* operator */
        char    *str;   /* string to push back */
} For;

#define MAXFOR  10

For     forstk[MAXFOR]; /* stack of for loops */
For     *forp = forstk; /* pointer to current top */

void forloop(Obj *var, double from, double to, int op, double by, char *str)    /* set up a for loop */
{
        fprintf(tfd, "# for %s from %g to %g by %c %g \n",
                var->name, from, to, op, by);
        if (++forp >= forstk+MAXFOR)
                ERROR "for loop nested too deep" FATAL;
        forp->var = var;
        forp->to = to;
        forp->op = op;
        forp->by = by;
        forp->str = str;
        setvar(var, from);
        nextfor();
        unput('\n');
}

void nextfor(void)      /* do one iteration of a for loop */
{
        /* BUG:  this should depend on op and direction */
        if (forp->var->fval > SLOP * forp->to) {        /* loop is done */
                free(forp->str);
                if (--forp < forstk)
                        ERROR "forstk popped too far" FATAL;
        } else {                /* another iteration */
                pushsrc(String, "\nEndfor\n");
                pushsrc(String, forp->str);
        }
}

void endfor(void)       /* end one iteration of for loop */
{
        switch (forp->op) {
        case '+':
        case ' ':
                forp->var->fval += forp->by;
                break;
        case '-':
                forp->var->fval -= forp->by;
                break;
        case '*':
                forp->var->fval *= forp->by;
                break;
        case '/':
                forp->var->fval /= forp->by;
                break;
        }
        nextfor();
}

char *ifstat(double expr, char *thenpart, char *elsepart)
{
        dprintf("if %g then <%s> else <%s>\n", expr, thenpart, elsepart? elsepart : "");
        if (expr) {
                unput('\n');
                pushsrc(Free, thenpart);
                pushsrc(String, thenpart);
                unput('\n');
                if (elsepart)
                        free(elsepart);
                return thenpart;        /* to be freed later */
        } else {
                free(thenpart);
                if (elsepart) {
                        unput('\n');
                        pushsrc(Free, elsepart);
                        pushsrc(String, elsepart);
                        unput('\n');
                }
                return elsepart;
        }
}