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#include "parser/parser_functions.h"
#include "parser/parser_utils.h"
struct ast *parse_rule_if(struct lexer *lexer, enum parser_state *state)
{
struct token next = lexer_peek(lexer);
// Not mandatory because we checked before going in here
if (next.type != TOKEN_IF)
{
QUICK_CLEANUP
}
struct ast *root = ast_create(AST_IF);
if (root == NULL)
{
*state = ERROR;
return NULL;
}
lexer_pop(lexer);
struct ast *cond = parse_compound_list(lexer, state);
next = lexer_peek(lexer);
if (error_check(root, state, next))
{
return NULL;
}
set_left(root, cond);
if (next.type != TOKEN_THEN)
{
cleanup(root, state);
return NULL;
}
lexer_pop(lexer);
cond = parse_compound_list(lexer, state);
next = lexer_peek(lexer);
if (error_check(root, state, next))
{
return NULL;
}
if (cond == NULL)
{
cleanup(root, state);
return NULL;
}
set_right(root, cond);
if (next.type != TOKEN_FI)
{
cond = parse_else_clause(lexer, state);
if (cond == NULL)
{
cleanup(root, state);
return NULL;
}
set_i(root, cond, 2);
}
lexer_pop(lexer);
return root;
}
struct ast *parse_else_clause(struct lexer *lexer, enum parser_state *state)
{
struct token next = lexer_peek(lexer);
struct ast *root = NULL;
if (next.type == TOKEN_ELSE)
{
lexer_pop(lexer);
struct ast *cond = parse_compound_list(lexer, state);
if (cond == NULL)
{
cleanup(root, state);
return NULL;
}
if (error_check(cond, state, next))
{
return NULL;
}
return cond;
}
else if (next.type != TOKEN_ELIF)
{
cleanup(NULL, state);
return NULL;
}
lexer_pop(lexer);
// Doesn' it seems stupid to just manually re-creating the IF again?
// Can't I just call parse_if there ? But we won't be following the grammar
// This is a late-game optimization that might not be worth it
root = ast_create(AST_IF);
if (root == NULL)
{
cleanup(root, state);
return NULL;
}
struct ast *cond = parse_compound_list(lexer, state);
set_left(root, cond);
if (error_check(root, state, next))
{
return NULL;
}
next = lexer_peek(lexer);
if (next.type != TOKEN_THEN)
{
cleanup(root, state);
return NULL;
}
lexer_pop(lexer);
set_right(root, parse_compound_list(lexer, state));
if (error_check(root, state, next))
{
return NULL;
}
next = lexer_peek(lexer);
if (next.type == TOKEN_ELSE || next.type == TOKEN_ELIF)
{
cond = parse_else_clause(lexer, state);
if (error_check(root, state, next))
{
return NULL;
}
set_i(root, cond, 2);
}
return root;
}
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