ref: 6a791a854e1ba78061cd84b19c4c3f6c5ae1128d dir: /examples/username.peg/
%{ #include <unistd.h> %} start = "username" { printf("%s", getlogin()); } | < . > { putchar(yytext[0]); } %% int main() { while (yyparse()); return 0; }