expression.c

/*
 * Expression.c
 * Implementation of functions used to build the syntax tree.
 */

#include "expression.h"

#include <stdlib.h>

/**
 * @brief Allocates space for expression
 * @return The expression or NULL if not enough memory
 */
static SExpression* allocateExpression() {
  SExpression* b = (SExpression *)malloc(sizeof *b);

  if (b == NULL)
    return NULL;

  b->type = eVALUE;
  b->value = 0;

  b->left = NULL;
  b->right = NULL;

  return b;
}

SExpression* createNumber(int value) {
  SExpression* b = allocateExpression();

  if (b == NULL)
    return NULL;

  b->type = eVALUE;
  b->value = value;

  return b;
}

SExpression* createString(const char *string) {
  SExpression* b = allocateExpression();

  if (b == NULL)
    return NULL;

  b->type = eSTRING;
  b->string = string;

  return b;
}


SExpression *createOperation(
    EOperationType type,
    SExpression *left,
    SExpression *right) {
  SExpression* b = allocateExpression();

  if (b == NULL)
    return NULL;

  b->type = type;
  b->left = left;
  b->right = right;

  return b;
}

void deleteExpression(SExpression *b) {
  if (b == NULL)
    return;

  deleteExpression(b->left);
  deleteExpression(b->right);

  free(b);
}