fish-shell/parse_productions.cpp

#include "parse_productions.h"

using namespace parse_productions;
#define NO_PRODUCTION ((production_option_idx_t)(-1))

static bool production_is_empty(const production_t production)
{
    return production[0] == token_type_invalid;
}

/* Empty productions are allowed but must be first. Validate that the given production is in the valid range, i.e. it is either not empty or there is a non-empty production after it */
static bool production_is_valid(const production_options_t production_list, production_option_idx_t which)
{
    if (which < 0 || which >= MAX_PRODUCTIONS)
        return false;

    bool nonempty_found = false;
    for (int i=which; i < MAX_PRODUCTIONS; i++)
    {
        if (! production_is_empty(production_list[i]))
        {
            nonempty_found = true;
            break;
        }
    }
    return nonempty_found;
}

/* Helper function indicates whether a token (typically second token) causes the preceding token to be treated as a command instead of giving it a special role. This is so we can treat e.g. 'command --help' as "invoke the 'command' builtin with --help' instead of 'run the --help command'.

    if naked_invocation_invokes_help is true, then we treat an invalid type or something other than a string as indicating help; this means that the user ran e.g. 'command' with no arguments.
*/
static inline bool token_implies_previous_keyword_is_command(parse_token_type_t type, parse_keyword_t keyword, bool naked_invocation_invokes_help)
{
    bool result = false;
    switch (keyword)
    {
        case parse_keyword_dash:
        case parse_keyword_dashdash:
        case parse_keyword_dash_h:
        case parse_keyword_dashdash_help:
            result = true;
            break;
            
        default:
            break;
    }
    
    if (! result)
    {
        result = naked_invocation_invokes_help && type != parse_token_type_string;
    }
    
    return result;
}

#define PRODUCTIONS(sym) static const production_options_t productions_##sym
#define RESOLVE(sym) static production_option_idx_t resolve_##sym (parse_token_type_t token_type, parse_keyword_t token_keyword, parse_token_type_t token_type2, parse_keyword_t token_keyword2)
#define RESOLVE_ONLY(sym) static production_option_idx_t resolve_##sym (parse_token_type_t token_type, parse_keyword_t token_keyword, parse_token_type_t token_type2, parse_keyword_t token_keyword2) { return 0; }

#define KEYWORD(x) ((x) + LAST_TOKEN_OR_SYMBOL + 1)


/* A job_list is a list of jobs, separated by semicolons or newlines */
PRODUCTIONS(job_list) =
{
    {},
    {symbol_job, symbol_job_list},
    {parse_token_type_end, symbol_job_list}
};

RESOLVE(job_list)
{
    switch (token_type)
    {
        case parse_token_type_string:
            // 'end' is special
            switch (token_keyword)
            {
                case parse_keyword_end:
                case parse_keyword_else:
                    // End this job list
                    return 0;

                default:
                    // Normal string
                    return 1;
            }

        case parse_token_type_pipe:
        case parse_token_type_redirection:
        case parse_token_type_background:
            return 1;

        case parse_token_type_end:
            // Empty line
            return 2;

        case parse_token_type_terminate:
            // no more commands, just transition to empty
            return 0;

        default:
            return NO_PRODUCTION;
    }
}

/* A job is a non-empty list of statements, separated by pipes. (Non-empty is useful for cases like if statements, where we require a command). To represent "non-empty", we require a statement, followed by a possibly empty job_continuation */

PRODUCTIONS(job) =
{
    {symbol_statement, symbol_job_continuation}
};
RESOLVE_ONLY(job)

PRODUCTIONS(job_continuation) =
{
    {},
    {parse_token_type_pipe, symbol_statement, symbol_job_continuation}
};
RESOLVE(job_continuation)
{
    switch (token_type)
    {
        case parse_token_type_pipe:
            // Pipe, continuation
            return 1;

        default:
            // Not a pipe, no job continuation
            return 0;
    }
}

/* A statement is a normal command, or an if / while / and etc */
PRODUCTIONS(statement) =
{
    {symbol_boolean_statement},
    {symbol_block_statement},
    {symbol_if_statement},
    {symbol_switch_statement},
    {symbol_decorated_statement}
};
RESOLVE(statement)
{
    // Go to decorated statements if the subsequent token looks like '--help'
    // If we are 'begin', then we expect to be invoked with no arguments. But if we are anything else, we require an argument, so do the same thing if the subsequent token is a line end.
    if (token_type == parse_token_type_string)
    {
        bool naked_invocation_invokes_help = (token_keyword != parse_keyword_begin && token_keyword != parse_keyword_end);
        if (token_implies_previous_keyword_is_command(token_type2, token_keyword2, naked_invocation_invokes_help))
        {
            return 4; //decorated statement
        }
    }

    switch (token_type)
    {
        case parse_token_type_string:
            switch (token_keyword)
            {
                case parse_keyword_and:
                case parse_keyword_or:
                case parse_keyword_not:
                    return 0;

                case parse_keyword_for:
                case parse_keyword_while:
                case parse_keyword_function:
                case parse_keyword_begin:
                    return 1;

                case parse_keyword_if:
                    return 2;

                case parse_keyword_else:
                    return NO_PRODUCTION;

                case parse_keyword_switch:
                    return 3;

                case parse_keyword_end:
                    return NO_PRODUCTION;

                    // 'in' is only special within a for_header
                case parse_keyword_in:
                case parse_keyword_none:
                case parse_keyword_command:
                case parse_keyword_builtin:
                case parse_keyword_case:
                case parse_keyword_dash:
                case parse_keyword_dashdash:
                case parse_keyword_dash_h:
                case parse_keyword_dashdash_help:
                    return 4;
            }
            break;

        case parse_token_type_pipe:
        case parse_token_type_redirection:
        case parse_token_type_background:
        case parse_token_type_terminate:
            return NO_PRODUCTION;
            //parse_error(L"statement", token);

        default:
            return NO_PRODUCTION;
    }
}

PRODUCTIONS(if_statement) =
{
    {symbol_if_clause, symbol_else_clause, KEYWORD(parse_keyword_end), symbol_arguments_or_redirections_list}
};
RESOLVE_ONLY(if_statement)

PRODUCTIONS(if_clause) =
{
    { KEYWORD(parse_keyword_if), symbol_job, parse_token_type_end, symbol_job_list }
};
RESOLVE_ONLY(if_clause)

PRODUCTIONS(else_clause) =
{
    { },
    { KEYWORD(parse_keyword_else), symbol_else_continuation }
};
RESOLVE(else_clause)
{
    switch (token_keyword)
    {
        case parse_keyword_else:
            return 1;
        default:
            return 0;
    }
}

PRODUCTIONS(else_continuation) =
{
    {symbol_if_clause, symbol_else_clause},
    {parse_token_type_end, symbol_job_list}
};
RESOLVE(else_continuation)
{
    switch (token_keyword)
    {
        case parse_keyword_if:
            return 0;
        default:
            return 1;
    }
}

PRODUCTIONS(switch_statement) =
{
    { KEYWORD(parse_keyword_switch), parse_token_type_string, parse_token_type_end, symbol_case_item_list, KEYWORD(parse_keyword_end)}
};
RESOLVE_ONLY(switch_statement)

PRODUCTIONS(case_item_list) =
{
    {},
    {symbol_case_item, symbol_case_item_list},
    {parse_token_type_end, symbol_case_item_list}
};
RESOLVE(case_item_list)
{
    if (token_keyword == parse_keyword_case) return 1;
    else if (token_type == parse_token_type_end) return 2; //empty line
    else return 0;
}

PRODUCTIONS(case_item) =
{
    {KEYWORD(parse_keyword_case), symbol_argument_list, parse_token_type_end, symbol_job_list}
};
RESOLVE_ONLY(case_item)

PRODUCTIONS(argument_list) =
{
    {},
    {symbol_argument, symbol_argument_list}
};
RESOLVE(argument_list)
{
    switch (token_type)
    {
        case parse_token_type_string:
            return 1;
        default:
            return 0;
    }
}

PRODUCTIONS(block_statement) =
{
    {symbol_block_header, parse_token_type_end, symbol_job_list, KEYWORD(parse_keyword_end), symbol_arguments_or_redirections_list}
};
RESOLVE_ONLY(block_statement)

PRODUCTIONS(block_header) =
{
    {symbol_for_header},
    {symbol_while_header},
    {symbol_function_header},
    {symbol_begin_header}
};
RESOLVE(block_header)
{
    switch (token_keyword)
    {
        case parse_keyword_else:
            return NO_PRODUCTION;
        case parse_keyword_for:
            return 0;
        case parse_keyword_while:
            return 1;
        case parse_keyword_function:
            return 2;
        case parse_keyword_begin:
            return 3;
        default:
            return NO_PRODUCTION;
    }
}

PRODUCTIONS(for_header) =
{
    {KEYWORD(parse_keyword_for), parse_token_type_string, KEYWORD(parse_keyword_in), symbol_arguments_or_redirections_list}
};
RESOLVE_ONLY(for_header)

PRODUCTIONS(while_header) =
{
    {KEYWORD(parse_keyword_while), symbol_statement}
};
RESOLVE_ONLY(while_header)

PRODUCTIONS(begin_header) =
{
    {KEYWORD(parse_keyword_begin)}
};
RESOLVE_ONLY(begin_header)

PRODUCTIONS(function_header) =
{
    {KEYWORD(parse_keyword_function), parse_token_type_string, symbol_argument_list}
};
RESOLVE_ONLY(function_header)

/* A boolean statement is AND or OR or NOT */
PRODUCTIONS(boolean_statement) =
{
    {KEYWORD(parse_keyword_and), symbol_statement},
    {KEYWORD(parse_keyword_or), symbol_statement},
    {KEYWORD(parse_keyword_not), symbol_statement}
};
RESOLVE(boolean_statement)
{
    switch (token_keyword)
    {
        case parse_keyword_and:
            return 0;
        case parse_keyword_or:
            return 1;
        case parse_keyword_not:
            return 2;
        default:
            return NO_PRODUCTION;
    }
}

PRODUCTIONS(decorated_statement) =
{
    {symbol_plain_statement},
    {KEYWORD(parse_keyword_command), symbol_plain_statement},
    {KEYWORD(parse_keyword_builtin), symbol_plain_statement},
};
RESOLVE(decorated_statement)
{
    /* If this is e.g. 'command --help' then the command is 'command' and not a decoration */
    if (token_implies_previous_keyword_is_command(token_type2, token_keyword2, true /* naked_invocation_is_help */))
        return 0;
    
    switch (token_keyword)
    {
        default:
            return 0;
        case parse_keyword_command:
            return 1;
        case parse_keyword_builtin:
            return 2;
    }
}

PRODUCTIONS(plain_statement) =
{
    {parse_token_type_string, symbol_arguments_or_redirections_list, symbol_optional_background}
};
RESOLVE_ONLY(plain_statement)

PRODUCTIONS(arguments_or_redirections_list) =
{
    {},
    {symbol_argument_or_redirection, symbol_arguments_or_redirections_list}
};
RESOLVE(arguments_or_redirections_list)
{
    switch (token_type)
    {
        case parse_token_type_string:
        case parse_token_type_redirection:
            return 1;
        default:
            return 0;
    }
}

PRODUCTIONS(argument_or_redirection) =
{
    {symbol_argument},
    {parse_token_type_redirection}
};
RESOLVE(argument_or_redirection)
{
    switch (token_type)
    {
        case parse_token_type_string:
            return 0;
        case parse_token_type_redirection:
            return 1;
        default:
            return NO_PRODUCTION;
    }
}

PRODUCTIONS(argument) =
{
    {parse_token_type_string}
};
RESOLVE_ONLY(argument)

PRODUCTIONS(redirection) =
{
    {parse_token_type_redirection}
};
RESOLVE_ONLY(redirection)

PRODUCTIONS(optional_background) =
{
    {},
    { parse_token_type_background }
};

RESOLVE(optional_background)
{
    switch (token_type)
    {
        case parse_token_type_background:
            return 1;
        default:
            return 0;
    }
}

#define TEST(sym) case (symbol_##sym): production_list = & productions_ ## sym ; resolver = resolve_ ## sym ; break;
const production_t *parse_productions::production_for_token(parse_token_type_t node_type, parse_token_type_t input_type, parse_keyword_t input_keyword, parse_token_type_t input_type2, parse_keyword_t input_keyword2, production_option_idx_t *out_which_production, wcstring *out_error_text)
{
    bool log_it = false;
    if (log_it)
    {
        fprintf(stderr, "Resolving production for %ls with input type %ls <%ls>\n", token_type_description(node_type).c_str(), token_type_description(input_type).c_str(), keyword_description(input_keyword).c_str());
    }

    /* Fetch the list of productions and the function to resolve them */
    const production_options_t *production_list = NULL;
    production_option_idx_t (*resolver)(parse_token_type_t token_type, parse_keyword_t token_keyword, parse_token_type_t token_type2, parse_keyword_t token_keyword2) = NULL;
    switch (node_type)
    {
            TEST(job_list)
            TEST(job)
            TEST(statement)
            TEST(job_continuation)
            TEST(boolean_statement)
            TEST(block_statement)
            TEST(if_statement)
            TEST(if_clause)
            TEST(else_clause)
            TEST(else_continuation)
            TEST(switch_statement)
            TEST(decorated_statement)
            TEST(case_item_list)
            TEST(case_item)
            TEST(argument_list)
            TEST(block_header)
            TEST(for_header)
            TEST(while_header)
            TEST(begin_header)
            TEST(function_header)
            TEST(plain_statement)
            TEST(arguments_or_redirections_list)
            TEST(argument_or_redirection)
            TEST(argument)
            TEST(redirection)
            TEST(optional_background)

        case parse_token_type_string:
        case parse_token_type_pipe:
        case parse_token_type_redirection:
        case parse_token_type_background:
        case parse_token_type_end:
        case parse_token_type_terminate:
            fprintf(stderr, "Terminal token type %ls passed to %s\n", token_type_description(node_type).c_str(), __FUNCTION__);
            PARSER_DIE();
            break;

        case parse_special_type_parse_error:
        case parse_special_type_tokenizer_error:
        case parse_special_type_comment:
            fprintf(stderr, "Special type %ls passed to %s\n", token_type_description(node_type).c_str(), __FUNCTION__);
            PARSER_DIE();
            break;


        case token_type_invalid:
            fprintf(stderr, "token_type_invalid passed to %s\n", __FUNCTION__);
            PARSER_DIE();
            break;

    }
    PARSE_ASSERT(production_list != NULL);
    PARSE_ASSERT(resolver != NULL);

    const production_t *result = NULL;
    production_option_idx_t which = resolver(input_type, input_keyword, input_type2, input_keyword2);

    if (log_it)
    {
        fprintf(stderr, "\tresolved to %u\n", (unsigned)which);
    }


    if (which == NO_PRODUCTION)
    {
        if (log_it)
        {
            fprintf(stderr, "Token type '%ls' has no production for input type '%ls', keyword '%ls' (in %s)\n", token_type_description(node_type).c_str(), token_type_description(input_type).c_str(), keyword_description(input_keyword).c_str(), __FUNCTION__);
        }
        result = NULL;
    }
    else
    {
        PARSE_ASSERT(production_is_valid(*production_list, which));
        result = &((*production_list)[which]);
    }
    *out_which_production = which;
    return result;
}