char.c

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

#include "error.h"
#include "number.h"
#include "char.h"
#include "util.h"

TYPE* 
mk_char(char c)
{
    TYPE* result = mloc(sizeof(TYPE));

    if (result == NULL)
    {
        fprintf(stderr, "MK_CHAR: could not allocate memory for type");
        exit(1);
    }

    result->type = CHAR;
    
    result->d.i = c;
        
    return result;
}

int
is_char(const TYPE* sexp)
{
    return sexp->type == CHAR;
}

int
is_char_equal(const TYPE* left, const TYPE* right)
{
    assert_throw(is_char(left),
		 TYPE_ERROR,
		 "IS_CHAR_EQUAL: left must be a char");
    assert_throw(is_char(right),
		 TYPE_ERROR,
		 "IS_CHAR_EQUAL: right must be a char");

    return left->d.i == right->d.i;
}

TYPE* 
char_to_integer(const TYPE* sexp)
{
    assert_throw(is_char(sexp),
                 TYPE_ERROR,
                 "CHAR_TO_INTEGER: argument must be a char");
    return mk_number_from_int(sexp->d.i);
}

TYPE* integer_to_char(const TYPE* sexp)
{
  assert_throw(is_number(sexp),	/* TODO numbers are integers now */
	       TYPE_ERROR,
	       "CHAR_TO_INTEGER: argument must be a integer");
  assert_throw(is_number_gt_eq(sexp, mk_number_from_int(0)),
	       TYPE_ERROR,
	       "CHAR_TO_INTEGER: argument < 0");
  assert_throw(is_number_lt_eq(sexp, mk_number_from_int(255)),
	       TYPE_ERROR,
	       "CHAR_TO_INTEGER: argument > 255");
  
  return mk_char((char) sexp->d.i);
}