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parser.c
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parser.c
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#include <stdlib.h>
#include <errno.h>
#include "lexer.h"
#include "parser.h"
int k_parse(struct k_token *tokens, size_t size)
{
int t = 0;
int *i = &t;
return k_expression(tokens, size, i);
}
int k_expression(struct k_token *tokens, size_t size, int *i)
{
int result = k_term(tokens, size, i);
while(*i < size && (tokens[*i].type == PLUS || tokens[*i].type == MINUS))
{
if(tokens[*i].type == PLUS)
{
(*i)++;
result = result + k_term(tokens, size, i);
}
else if(tokens[*i].type == MINUS)
{
(*i)++;
result = result - k_term(tokens, size, i);
}
else
{
exit(EXIT_FAILURE);
}
}
return result;
}
int k_term(struct k_token *tokens, size_t size, int *i)
{
int result = k_factor(tokens, size, i);
while(*i < size && (tokens[*i].type == MULTIPLY || tokens[*i].type == DIVIDE))
{
if(tokens[*i].type == MULTIPLY )
{
(*i)++;
result = result * k_factor(tokens, size, i);
}
else if(tokens[*i].type == DIVIDE)
{
(*i)++;
result = result / k_factor(tokens, size, i);
}
else
{
exit(EXIT_FAILURE);
}
}
return result;
}
int k_factor(struct k_token *tokens, size_t size, int *i){
int result;
if(tokens[*i].type == INTEGER)
{
result = strtol(tokens[*i].value, NULL, 10);
(*i)++;
}
else if(tokens[*i].type == LPAREN)
{
(*i)++;
result = k_expression(tokens, size, i);
if(tokens[*i].type != RPAREN)
{
exit(EXIT_FAILURE);
}
(*i)++;
}
else
{
exit(EXIT_FAILURE);
}
return result;
}