parsing.c

#include <stdio.h>
#include <stdlib.h>

#include "mpc.h"

#include <editline/readline.h>

int main(int argc, char** argv) {
  mpc_parser_t* Number = mpc_new("number");
  mpc_parser_t* Operator = mpc_new("operator");
  mpc_parser_t* Expr = mpc_new("expr");
  mpc_parser_t* Lispy = mpc_new("lispy");

  mpca_lang(MPCA_LANG_DEFAULT,
            "                                                     \
      number   : /-?[0-9]+/ ;                             \
      operator : '+' | '-' | '*' | '/' ;                  \
      expr     : <number> | '(' <operator> <expr>+ ')' ;  \
      lispy    : /^/ <operator> <expr>+ /$/ ;             \
    ",
            Number, Operator, Expr, Lispy);

  puts("Lispy 0.0.0.0.0.0.2");
  puts("Press C-c to exit.");

  while(1) {
    char *input = readline("lispy> ");
    add_history(input);

    mpc_result_t r;
    if(mpc_parse("<stdin>", input, Lispy, &r)) {
      /* On success, print AST */
      mpc_ast_print(r.output);
      mpc_ast_delete(r.output);
    } else {
      mpc_err_print(r.error);
      mpc_err_delete(r.error);
    }

    free(input);
  }

  mpc_cleanup(4, Number, Operator, Expr, Lispy);

  return 0;
}