> On 23 Feb 2019, at 23:19, workbe...@gmx.at <workbe...@gmx.at> wrote: > > Hi again, i have the following code:
Here is a slightly different code, for example with input "x1 y2 34 ? exit". The lexer will rescan unless there is an action return, which happens for "exit". Typically in a lexer, whitespace is eaten, dividing up the tokens. Otherwise, Flex has a mailing list, cf. https://en.wikipedia.org/wiki/Flex_(lexical_analyser_generator) The manual is good, too. Also, there is the Usenet newsgroup comp.compilers for general questions about parsing, mostly advanced. -- %{ #include <stdio.h> #include <stdlib.h> %} %option noyywrap identifier [[:alpha:]][[:alnum:]]* integer [[:digit:]]+ %% [ \f\r\t\v\n]+ { /* eat whitespace */ } "exit" { printf("Exit!\n"); return 0; } {identifier} { printf("%s is an identifer\n", yytext); } {integer} { printf("%s is an integer\n", yytext); } . { printf("/* %s: do nothing*/\n", yytext); } %% int main(int argc, char **argv) { printf("Start\n"); yylex(); printf("End\n"); return(0); } -- _______________________________________________ help-bison@gnu.org https://lists.gnu.org/mailman/listinfo/help-bison
