s_expression.cpp

/* -*- c++ -*- */
/*
 * Copyright © 2010 Intel Corporation
 *
 * 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 (including the next
 * paragraph) 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 <cstdio>
#include <cstdlib>
#include <cstring>
#include <assert.h>
#include "s_expression.h"

s_symbol::s_symbol(const char *tmp)
{
   this->str = talloc_strdup (this, tmp);
   assert(this->str != NULL);
}

s_list::s_list()
{
}

unsigned
s_list::length() const
{
   unsigned i = 0;
   foreach_iter(exec_list_iterator, it, this->subexpressions) {
      i++;
   }
   return i;
}

static s_expression *
read_atom(void *ctx, const char *& src)
{
   char buf[101];
   int n;
   if (sscanf(src, " %100[^( \v\t\r\n)]%n", buf, &n) != 1)
      return NULL; // no atom
   src += n;

   // Check if the atom is a number.
   char *float_end = NULL;
   double f = strtod(buf, &float_end);
   if (float_end != buf) {
      char *int_end = NULL;
      int i = strtol(buf, &int_end, 10);
      // If strtod matched more characters, it must have a decimal part
      if (float_end > int_end)
	 return new(ctx) s_float(f);

      return new(ctx) s_int(i);
   }
   // Not a number; return a symbol.
   return new(ctx) s_symbol(buf);
}

s_expression *
s_expression::read_expression(void *ctx, const char *&src)
{
   assert(src != NULL);

   s_expression *atom = read_atom(ctx, src);
   if (atom != NULL)
      return atom;

   char c;
   int n;
   if (sscanf(src, " %c%n", &c, &n) == 1 && c == '(') {
      src += n;

      s_list *list = new(ctx) s_list;
      s_expression *expr;

      while ((expr = read_expression(ctx, src)) != NULL) {
	 list->subexpressions.push_tail(expr);
      }
      if (sscanf(src, " %c%n", &c, &n) != 1 || c != ')') {
	 printf("Unclosed expression (check your parenthesis).\n");
	 return NULL;
      }
      src += n;
      return list;
   }
   return NULL;
}

void s_int::print()
{
   printf("%d", this->val);
}

void s_float::print()
{
   printf("%f", this->val);
}

void s_symbol::print()
{
   printf("%s", this->str);
}

void s_list::print()
{
   printf("(");
   foreach_iter(exec_list_iterator, it, this->subexpressions) {
      s_expression *expr = (s_expression*) it.get();
      expr->print();
      printf(" ");
   }
   printf(")");
}