eval_expression.c File Reference

#include <stdbool.h>
#include "evaluator.h"
#include "hashtable.h"
#include "module.h"
#include "types/operators.h"

Include dependency graph for eval_expression.c:

Go to the source code of this file.

Functions
int64_t	_op_binary_eval (int64_t a, operator_t op, int64_t b)
int64_t	_op_unary_eval (operator_t op, int64_t a)
int64_t	eval_expression (hashtable_t *variables, module_t *module, ast_node_t *ast)
	Evaluates a mathetical expression.

Function Documentation

_op_binary_eval()

int64_t _op_binary_eval ( int64_t a, operator_t op, int64_t b )

inline

Definition at line 63 of file eval_expression.c.

{
  switch (op) {
  case OP_DIV:
    return a / b;
  case OP_MULT:
    return a * b;
  case OP_MINUS:
    return a - b;
  case OP_PLUS:
    return a + b;
  case OP_SHIFT_LEFT:
    return a << b;
  case OP_SHIFT_RIGHT:
    return a >> b;
  case OP_AND:
    return a & b;
  case OP_XOR:
    return a ^ b;
  case OP_OR:
    return a | b;
  default:
    return 0;
  }
}

_op_unary_eval()

int64_t _op_unary_eval ( operator_t op, int64_t a )

inline

Definition at line 90 of file eval_expression.c.

{
  switch (op) {
  case OP_NOT:
    return ~a;
  case OP_NEGATE:
    return -a;
  default:
    return 0;
  }
}

eval_expression()

int64_t eval_expression	(	hashtable_t *	variables,
		module_t *	module,
		ast_node_t *	ast )

Evaluates a mathetical expression.

Parameters

variables	The hashtable with the declared variables.
module	Mya module where this expression is in.
ast	The AST node where start the expression.

Definition at line 15 of file eval_expression.c.

{
  int64_t result;
 
  if (ast->type != NT_EXPRESSION) {
    module_add_error(
      module,
      ast->token->line,
      ast->token->column,
      ast->token->lexeme.length,
      "Unexpected token inside an expression."
    );
 
    return 0;
  }
 
  switch (ast->token->type) {
  case TK_OPEN_PARENS:
    return eval_expression(variables, module, ast->children);
  case TK_NUMBER:
    return ast->token->value;
  case TK_IDENTIFIER:
    if (hashtable_get(variables, ast->token->lexeme.data, &result) != ERR_OK) {
      module_add_error(module, ast->token->line, ast->token->column, ast->token->lexeme.length, "Undefined variable.");
      return 0;
    }
 
    return result;
  case TK_OPERATOR:
    bool is_binary = (ast->children_count == 2);
    ast_node_t* a = &ast->children[0];
 
    if (is_binary) {
      ast_node_t* b = &ast->children[1];
      return _op_binary_eval(
        eval_expression(variables, module, a),
        ast->token->value,
        eval_expression(variables, module, b)
      );
    }
 
    return _op_unary_eval(ast->token->value, eval_expression(variables, module, a));
  default:
    return 0;
  }
}