mal_00.c

/* MIT License

Copyright (c) 2022 Bezdek Miroslav

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#include <ctype.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

struct lvm_s;
typedef struct lvm_s lvm_t, *lvm_p, **lvm_pp;

struct lvm_s {
  struct {
    char *str;
    size_t pos;
    size_t line;
    size_t column;
  } reader;
};


#if __STDC__
#ifndef __STDC_VERSION__
/* C89 */
char *strdup(char *str);
char *strndup(char *str, size_t n);
#else
char *strdup(const char *str);
char *strndup(const char *str, size_t n);
/* C90[+] */
#endif
#endif
char *readline(lvm_p this, char *prompt);
lvm_p lvm_make();
char *lvm_read(lvm_p this, char *str);
char *lvm_eval(lvm_p this, char *str);
char *lvm_print(lvm_p this, char *str);
char *lvm_rep(lvm_p this, char *str);

#if __STDC__
#ifndef __STDC_VERSION__
/* C89 */
char *strdup(char *str)
{
  char *result;
  char *p = str;
  size_t n = 0;

  while (*p++)
    n++;
  result = malloc(n * sizeof(char) + 1);
  p = result;
  while (*str)
    *p++ = *str++;
  *p = 0x00;
  return result;
}

char *strndup(char *str, size_t n)
{
  char *result;
  char *p;
  result = malloc(n * sizeof(char) + 1);
  p = result;
  while (*str)
    *p++ = *str++;
  *p = 0x00;
  return result;
}
#else
/* C90[+] */
#endif
#endif

char *readline(lvm_p this, char *prompt)
{
  char buffer[2048], *tmp;
  (void)this;
  printf("%s", prompt);
  fgets(buffer, sizeof(buffer), stdin);
  if (feof(stdin)) {
    return NULL;
  }
  buffer[strcspn(buffer, "\r\n")] = 0x00;
  tmp = (char *)strndup(buffer, strlen(buffer));
  return tmp;
}

lvm_p lvm_make()
{
  lvm_p lvm = (lvm_p)calloc(1, sizeof(lvm_t));
  lvm->reader.str = NULL;
  lvm->reader.pos = 0;
  lvm->reader.line = 1;
  lvm->reader.column = 0;
  return lvm;
}

void lvm_free(lvm_pp this)
{
  free((void *)(*this));
  (*this) = NULL;
  return;
}

char *lvm_read(lvm_p this, char *str)
{
  this->reader.str = str;
  this->reader.pos = 0;
  return str;
}

char *lvm_eval(lvm_p this, char *str)
{
  (void)this;
  return str;
}

char *lvm_print(lvm_p this, char *str)
{
  char *output = strdup(str);
  (void)this;
  return output;
}

char *lvm_rep(lvm_p this, char *str)
{
  return lvm_print(this, lvm_eval(this, lvm_read(this, str)));
}

int main(int argc, char *argv[])
{
  lvm_p lvm = lvm_make();
  (void)argc;
  (void)argv;
  puts("Make-a-lisp version 0.0.0\n");
  puts("Press Ctrl+D to exit\n");
  while (1) {
    char *input = readline(lvm, "mal> ");
    char *output = NULL;
    if (!input) {
      putchar('\n');
      break;
    }
    output = lvm_rep(lvm, input);
    if (0x00 != output[0x00]) {
      printf("%s\n", output);
    }
    free((void *)output);
    free((void *)input);
  }
  lvm_free(&lvm);
  return 0;
}