path: root/42sh/src/parser/parser_loops.c

#include <err.h>

#include "parser_functions.h"
#include "parser_utils.h"

struct ast *parse_rule_while(struct lexer *lexer, enum parser_state *state)
{
    struct token next = lexer_peek(lexer);

    // Because we use this function for both while and until loops, this needs
    // to be accounted for. The construction is exactly the same otherwise.
    // The only difference is that the condition is NOT'ed in parse_rule_until
    if (next.type != TOKEN_WHILE && next.type != TOKEN_UNTIL)
    {
        QUICK_CLEANUP
    }

    lexer_pop(lexer);
    next = lexer_peek(lexer);

    struct ast *cond = parse_compound_list(lexer, state);
    next = lexer_peek(lexer);

    if (error_check(NULL, state, next))
    {
        return NULL;
    }

    if (next.type != TOKEN_DO)
    {
        cleanup(cond, state);
        return NULL;
    }

    lexer_pop(lexer);

    struct ast *body = parse_compound_list(lexer, state);
    next = lexer_peek(lexer);

    if (error_check(cond, state, next))
    {
        return NULL;
    }

    if (next.type != TOKEN_DONE)
    {
        cleanup(cond, state);
        cleanup(body, state);
        return NULL;
    }

    lexer_pop(lexer);

    struct ast *while_loop = ast_create(AST_WHILE);

    if (while_loop == NULL)
    {
        cleanup(cond, state);
        cleanup(body, state);
        return NULL;
    }

    set_left(while_loop, cond);
    set_right(while_loop, body);

    return while_loop;
}

// Warning, does not respect the grammar for parse_rule_until.
// This is because we reuse the parse_rule_while method (the ast representation
// being exatly the same, minus the condition being negated)
struct ast *parse_rule_until(struct lexer *lexer, enum parser_state *state)
{
    struct token next = lexer_peek(lexer);

    if (next.type != TOKEN_UNTIL)
    {
        QUICK_CLEANUP
    }

    struct ast *while_root = parse_rule_while(lexer, state);
    next = lexer_peek(lexer);

    if (error_check(while_root, state, next))
    {
        return NULL;
    }

    struct ast *inverted = ast_create(AST_LOGICAL);
    if (inverted == NULL)
    {
        cleanup(while_root, state);
        return NULL;
    }

    ((struct ast_logical *)inverted)->type = TOKEN_NEG;

    set_left(inverted, ((struct ast_while *)while_root)->cond);
    ((struct ast_while *)while_root)->cond = inverted;

    return while_root;
}

static struct string **_realloc_ast_command(struct ast *ast, size_t *capacity)
{
    struct ast_command *ast_c = ((struct ast_command *)ast);
    size_t i = 0;
    while (ast_c->args[i])
    {
        i++;
    }
    struct string **p =
        realloc(ast_c->args, (i + CMDSIZE) * sizeof(struct string *));
    if (!p)
    {
        errx(EXIT_FAILURE, "Realloc failed.");
    }
    ast_c->args = p;
    *capacity = i + CMDSIZE;
    memset(ast_c->args + i, 0, (CMDSIZE) * sizeof(struct string *));
    return p;
}

static void fill_cmd(struct ast *ast, struct lexer *lexer)
{
    struct token next = lexer_peek(lexer);
    size_t i = 0;
    size_t capacity = CMDSIZE;

    struct string **arr = calloc(CMDSIZE, sizeof(struct string *));

    ((struct ast_command *)ast)->args = arr;
    while (ISWORD(next.type))
    {
        if (i == capacity)
        {
            arr = _realloc_ast_command(ast, &capacity);
            ((struct ast_command *)ast)->args = arr;
        }

        litteral_reserved_word(&next);
        arr[i] = next.value;
        i++;
        lexer_pop(lexer);
        next = lexer_peek(lexer);
    }
}

static struct ast *fill_for_body(struct ast *root, struct lexer *lexer,
                                 enum parser_state *state)
{
    clean_cons_tokens(TOKEN_NEWLINE, lexer);

    struct token next = lexer_peek(lexer);

    if (next.type != TOKEN_DO)
    {
        cleanup(root, state);
        return NULL;
    }

    lexer_pop(lexer);
    next = lexer_peek(lexer);

    struct ast *cmp_lst = parse_compound_list(lexer, state);

    next = lexer_peek(lexer);
    if (error_check(root, state, next))
    {
        return NULL;
    }

    set_right(root, cmp_lst);

    if (next.type != TOKEN_DONE)
    {
        cleanup(root, state);
        return NULL;
    }

    lexer_pop(lexer);

    return root;
}

struct ast *parse_rule_for(struct lexer *lexer, enum parser_state *state)
{
    struct token next = lexer_peek(lexer);

    if (next.type != TOKEN_FOR)
    {
        QUICK_CLEANUP;
    }

    lexer_pop(lexer);
    next = lexer_peek(lexer);

    // It can be a keyword interpreted as a normal word
    litteral_reserved_word(&next);
    struct ast *for_node = ast_create(AST_FOR);

    // Cannot do both at the same time because I couldn't know why the code exit
    // Was it because of the tokenor the ast and should I free something ?
    if (for_node == NULL)
    {
        QUICK_CLEANUP;
    }

    if (!(ISWORD(next.type)))
    {
        cleanup(for_node, state);
        return NULL;
    }

    ((struct ast_for *)for_node)->var = next.value;

    lexer_pop(lexer);
    next = lexer_peek(lexer);

    if (next.type == TOKEN_SEMICOLON)
    {
        lexer_pop(lexer);
    }
    else if (next.type == TOKEN_NEWLINE || next.type == TOKEN_IN)
    {
        if (next.type == TOKEN_NEWLINE)
        {
            clean_cons_tokens(TOKEN_NEWLINE, lexer);
            // We only need to peek if we destroyed tokens
            next = lexer_peek(lexer);
        }

        if (next.type == TOKEN_IN)
        {
            lexer_pop(lexer);
            next = lexer_peek(lexer);

            struct ast *lst = ast_create(AST_COMMAND);
            if (lst == NULL)
            {
                cleanup(for_node, state);
                return NULL;
            }

            fill_cmd(lst, lexer);
            set_left(for_node, lst);

            next = lexer_peek(lexer);
            if (next.type != TOKEN_SEMICOLON && next.type != TOKEN_NEWLINE)
            {
                cleanup(for_node, state);
                return NULL;
            }

            lexer_pop(lexer);
        }
    }
    else if (next.type != TOKEN_DO)
    {
        cleanup(for_node, state);
        return NULL;
    }

    return fill_for_body(for_node, lexer, state);
}