ref: ae4450b8dcb2e8f127ebad88d6f01fb0a18ee544
dir: /sys/src/liblex/yyless.c/
#include <u.h> #include <libc.h> #include <stdio.h> extern char yytext[]; extern int yyleng; extern int yyprevious; void yyunput(int c); void yyless(int x) { char *lastch, *ptr; lastch = yytext+yyleng; if(x>=0 && x <= yyleng) ptr = x + yytext; else ptr = (char*)x; while(lastch > ptr) yyunput(*--lastch); *lastch = 0; if (ptr >yytext) yyprevious = lastch[-1]; yyleng = ptr-yytext; }