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|
%{
#include <string.h>
#include <stdio.h>
#include <limits.h>
#include "iburg.h"
static char rcsid[] = "$Id: gram.y 71 2006-12-11 01:22:25Z drhanson $";
static int yylineno = 0;
%}
%union {
int n;
char *string;
Tree tree;
}
%term TERMINAL
%term START
%term PPERCENT
%token <string> ID
%token <n> INT
%type <string> lhs
%type <tree> tree
%type <n> cost
%%
spec : decls PPERCENT rules { yylineno = 0; }
| decls { yylineno = 0; }
;
decls : /* lambda */
| decls decl
;
decl : TERMINAL blist '\n'
| START lhs '\n' {
if (nonterm($2)->number != 1)
yyerror("redeclaration of the start symbol\n");
}
| '\n'
| error '\n' { yyerrok; }
;
blist : /* lambda */
| blist ID '=' INT { term($2, $4); }
;
rules : /* lambda */
| rules lhs ':' tree '=' INT cost ';' '\n' { rule($2, $4, $6, $7); }
| rules '\n'
| rules error '\n' { yyerrok; }
;
lhs : ID { nonterm($$ = $1); }
;
tree : ID { $$ = tree($1, NULL, NULL); }
| ID '(' tree ')' { $$ = tree($1, $3, NULL); }
| ID '(' tree ',' tree ')' { $$ = tree($1, $3, $5); }
;
cost : /* lambda */ { $$ = 0; }
| '(' INT ')' { if ($2 > maxcost) {
yyerror("%d exceeds maximum cost of %d\n", $2, maxcost);
$$ = maxcost;
} else
$$ = $2; }
;
%%
#include <stdarg.h>
#include <ctype.h>
int errcnt = 0;
FILE *infp = NULL;
FILE *outfp = NULL;
static char buf[BUFSIZ], *bp = buf;
static int ppercent = 0;
static int get(void) {
if (*bp == 0) {
bp = buf;
*bp = 0;
if (fgets(buf, sizeof buf, infp) == NULL)
return EOF;
yylineno++;
while (buf[0] == '%' && buf[1] == '{' && (buf[2] == '\n' || buf[2] == '\r')) {
for (;;) {
if (fgets(buf, sizeof buf, infp) == NULL) {
yywarn("unterminated %{...%}\n");
return EOF;
}
yylineno++;
if (strcmp(buf, "%}\n") == 0 || strcmp(buf, "%}\r\n") == 0)
break;
fputs(buf, outfp);
}
if (fgets(buf, sizeof buf, infp) == NULL)
return EOF;
yylineno++;
}
}
return *bp++;
}
void yyerror(char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
if (yylineno > 0)
fprintf(stderr, "line %d: ", yylineno);
vfprintf(stderr, fmt, ap);
if (fmt[strlen(fmt)-1] != '\n')
fprintf(stderr, "\n");
errcnt++;
}
int yylex(void) {
int c;
while ((c = get()) != EOF) {
switch (c) {
case ' ': case '\f': case '\t': case '\r':
continue;
case '\n':
case '(': case ')': case ',':
case ';': case '=': case ':':
return c;
}
if (c == '%' && *bp == '%') {
bp++;
return ppercent++ ? 0 : PPERCENT;
} else if (c == '%' && strncmp(bp, "term", 4) == 0
&& isspace(bp[4])) {
bp += 4;
return TERMINAL;
} else if (c == '%' && strncmp(bp, "start", 5) == 0
&& isspace(bp[5])) {
bp += 5;
return START;
} else if (isdigit(c)) {
int n = 0;
do {
int d = c - '0';
if (n > (INT_MAX - d)/10)
yyerror("integer greater than %d\n", INT_MAX);
else
n = 10*n + d;
c = get();
} while (c != EOF && isdigit(c));
bp--;
yylval.n = n;
return INT;
} else if (isalpha(c)) {
char *p = bp - 1;
while (isalpha(*bp) || isdigit(*bp) || *bp == '_')
bp++;
yylval.string = alloc(bp - p + 1);
strncpy(yylval.string, p, bp - p);
yylval.string[bp - p] = 0;
return ID;
} else if (isprint(c))
yyerror("invalid character `%c'\n", c);
else
yyerror("invalid character `\\%03o'\n", (unsigned char)c);
}
return 0;
}
void yywarn(char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
if (yylineno > 0)
fprintf(stderr, "line %d: ", yylineno);
fprintf(stderr, "warning: ");
vfprintf(stderr, fmt, ap);
}
|
