mirror of
https://github.com/9fans/plan9port.git
synced 2025-01-15 11:20:03 +00:00
96 lines
1.9 KiB
C
96 lines
1.9 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include "pic.h"
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#include "y.tab.h"
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#define SLOP 1.001
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typedef struct {
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char *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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For forstk[10]; /* stack of for loops */
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For *forp = forstk; /* pointer to current top */
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void setfval(char *, double);
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void nextfor(void);
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void forloop(char *var, double from, double to, int op,
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double by, char *str) /* set up a for loop */
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{
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dprintf("# for %s from %g to %g by %c %g \n",
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var, from, to, op, by);
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if (++forp >= forstk+10)
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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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setfval(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 (getfval(forp->var) > 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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struct symtab *p = lookup(forp->var);
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switch (forp->op) {
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case '+':
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case ' ':
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p->s_val.f += forp->by;
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break;
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case '-':
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p->s_val.f -= forp->by;
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break;
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case '*':
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p->s_val.f *= forp->by;
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break;
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case '/':
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p->s_val.f /= 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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}
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