diff options
author | ridiculousfish <corydoras@ridiculousfish.com> | 2015-12-15 14:59:03 -0800 |
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committer | ridiculousfish <corydoras@ridiculousfish.com> | 2015-12-19 11:17:13 -0800 |
commit | 8c707a4e2ffc30bae6d9ac3a28bd05fca0ff1195 (patch) | |
tree | 786b8ac916b5c873be902e8e3a1cbf9b38aaf53c /src/parse_productions.cpp | |
parent | 7188d94c1bdc483e6dca877631ca6dfa6af0ebbc (diff) |
Simplify parser implementation
Rather than returning a list of productions and an index,
return the relevant production directly from the rule function.
Also introduce a tag value (replacing production_idx) which tracks
information like command decorations, etc. with more clarity.
Diffstat (limited to 'src/parse_productions.cpp')
-rw-r--r-- | src/parse_productions.cpp | 391 |
1 files changed, 137 insertions, 254 deletions
diff --git a/src/parse_productions.cpp b/src/parse_productions.cpp index 0d28c6a1..4d1ec227 100644 --- a/src/parse_productions.cpp +++ b/src/parse_productions.cpp @@ -4,49 +4,37 @@ #include "parse_tree.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; -} +#define NO_PRODUCTION NULL -/* 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) -{ - assert(which >= 0); - if (which >= MAX_PRODUCTIONS) - return false; +/* Herein are encoded the productions for our LL2 fish grammar. + Each symbol (e.g. symbol_job_list) has a corresponding function (e.g. resolve_job_lits). + The function accepts two tokens, representing the first and second lookahead, and returns + returns a production representing the rule, or NULL on error. There is also a tag value + which is returned by reference; the tag is a sort of node annotation. + + Productions are generally a static const array, and we return a pointer to the array (yes, really). + */ - 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; -} +#define RESOLVE(sym) static const production_t * resolve_##sym (const parse_token_t &token1, const parse_token_t &token2, parse_node_tag_t *out_tag) -#define PRODUCTIONS(sym) static const production_options_t productions_##sym -#define RESOLVE(sym) static production_option_idx_t resolve_##sym (const parse_token_t &token1, const parse_token_t &token2) -#define RESOLVE_ONLY(sym) static production_option_idx_t resolve_##sym (const parse_token_t &input1, const parse_token_t &input2) { return 0; } +/* Hacktastic? */ +#define RESOLVE_ONLY(sym) \ + extern const production_t sym##_only; \ + static const production_t * resolve_##sym (const parse_token_t &token1, const parse_token_t &token2, parse_node_tag_t *out_tag) { return &sym ## _only ; } \ + const production_t sym ## _only #define KEYWORD(x) ((x) + LAST_TOKEN_OR_SYMBOL + 1) +/* Helper macro to define an array */ +#define P static const production_t /* 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) { + P list_end = {}; + P normal = {symbol_job, symbol_job_list}; + P empty_line = {parse_token_type_end, symbol_job_list}; switch (token1.type) { case parse_token_type_string: @@ -57,25 +45,24 @@ RESOLVE(job_list) case parse_keyword_else: case parse_keyword_case: // End this job list - return 0; + return &list_end; default: // Normal string - return 1; + return &normal; } case parse_token_type_pipe: case parse_token_type_redirection: case parse_token_type_background: - return 1; + return &normal; case parse_token_type_end: - // Empty line - return 2; + return &empty_line; case parse_token_type_terminate: // no more commands, just transition to empty - return 0; + return &list_end; default: return NO_PRODUCTION; @@ -84,42 +71,32 @@ RESOLVE(job_list) /* 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, symbol_optional_background} -}; -RESOLVE_ONLY(job) +RESOLVE_ONLY(job) = {symbol_statement, symbol_job_continuation, symbol_optional_background}; -PRODUCTIONS(job_continuation) = -{ - {}, - {parse_token_type_pipe, symbol_statement, symbol_job_continuation} -}; RESOLVE(job_continuation) { + P empty = {}; + P piped = {parse_token_type_pipe, symbol_statement, symbol_job_continuation}; switch (token1.type) { case parse_token_type_pipe: // Pipe, continuation - return 1; + return &piped; default: // Not a pipe, no job continuation - return 0; + return ∅ } } /* 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) { + P boolean = {symbol_boolean_statement}; + P block = {symbol_block_statement}; + P ifs = {symbol_if_statement}; + P switchs = {symbol_switch_statement}; + P decorated = {symbol_decorated_statement}; /* The only block-like builtin that takes any parameters is 'function' So go to decorated statements if the subsequent token looks like '--'. The logic here is subtle: If we are 'begin', then we expect to be invoked with no arguments. @@ -133,18 +110,18 @@ RESOLVE(statement) // Otherwise, if the next token looks like an option (starts with a dash), then parse it as a decorated statement if (token1.keyword == parse_keyword_function && token2.is_help_argument) { - return 4; + return &decorated; } else if (token1.keyword != parse_keyword_function && token2.has_dash_prefix) { - return 4; + return &decorated; } // Likewise if the next token doesn't look like an argument at all. This corresponds to e.g. a "naked if". bool naked_invocation_invokes_help = (token1.keyword != parse_keyword_begin && token1.keyword != parse_keyword_end); if (naked_invocation_invokes_help && (token2.type == parse_token_type_end || token2.type == parse_token_type_terminate)) { - return 4; + return &decorated; } } @@ -157,29 +134,29 @@ RESOLVE(statement) case parse_keyword_and: case parse_keyword_or: case parse_keyword_not: - return 0; + return &boolean; case parse_keyword_for: case parse_keyword_while: case parse_keyword_function: case parse_keyword_begin: - return 1; + return █ case parse_keyword_if: - return 2; + return &ifs; case parse_keyword_else: return NO_PRODUCTION; case parse_keyword_switch: - return 3; + return &switchs; case parse_keyword_end: return NO_PRODUCTION; // All other keywords fall through to decorated statement default: - return 4; + return &decorated; } break; @@ -195,294 +172,216 @@ RESOLVE(statement) } } -PRODUCTIONS(if_statement) = -{ - {symbol_if_clause, symbol_else_clause, symbol_end_command, 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) +RESOLVE_ONLY(if_statement) = {symbol_if_clause, symbol_else_clause, symbol_end_command, symbol_arguments_or_redirections_list}; +RESOLVE_ONLY(if_clause) = { KEYWORD(parse_keyword_if), symbol_job, parse_token_type_end, symbol_job_list }; -PRODUCTIONS(else_clause) = -{ - { }, - { KEYWORD(parse_keyword_else), symbol_else_continuation } -}; RESOLVE(else_clause) { + P empty = {}; + P else_cont = { KEYWORD(parse_keyword_else), symbol_else_continuation }; switch (token1.keyword) { case parse_keyword_else: - return 1; + return &else_cont; default: - return 0; + return ∅ } } -PRODUCTIONS(else_continuation) = -{ - {symbol_if_clause, symbol_else_clause}, - {parse_token_type_end, symbol_job_list} -}; RESOLVE(else_continuation) { + P elseif = {symbol_if_clause, symbol_else_clause}; + P elseonly = {parse_token_type_end, symbol_job_list}; + switch (token1.keyword) { case parse_keyword_if: - return 0; + return &elseif; default: - return 1; + return &elseonly; } } -PRODUCTIONS(switch_statement) = -{ - { KEYWORD(parse_keyword_switch), symbol_argument, parse_token_type_end, symbol_case_item_list, symbol_end_command, symbol_arguments_or_redirections_list} -}; -RESOLVE_ONLY(switch_statement) +RESOLVE_ONLY(switch_statement) = { KEYWORD(parse_keyword_switch), symbol_argument, parse_token_type_end, symbol_case_item_list, symbol_end_command, symbol_arguments_or_redirections_list}; -PRODUCTIONS(case_item_list) = -{ - {}, - {symbol_case_item, symbol_case_item_list}, - {parse_token_type_end, symbol_case_item_list} -}; RESOLVE(case_item_list) { - if (token1.keyword == parse_keyword_case) return 1; - else if (token1.type == parse_token_type_end) return 2; //empty line - else return 0; + P empty = {}; + P case_item = {symbol_case_item, symbol_case_item_list}; + P blank_line = {parse_token_type_end, symbol_case_item_list}; + if (token1.keyword == parse_keyword_case) return &case_item; + else if (token1.type == parse_token_type_end) return &blank_line; + else return ∅ } -PRODUCTIONS(case_item) = -{ - {KEYWORD(parse_keyword_case), symbol_argument_list, parse_token_type_end, symbol_job_list} -}; -RESOLVE_ONLY(case_item) +RESOLVE_ONLY(case_item) = {KEYWORD(parse_keyword_case), symbol_argument_list, parse_token_type_end, symbol_job_list}; -PRODUCTIONS(argument_list) = -{ - {}, - {symbol_argument, symbol_argument_list} -}; RESOLVE(argument_list) { + P empty = {}; + P arg = {symbol_argument, symbol_argument_list}; switch (token1.type) { case parse_token_type_string: - return 1; + return &arg; default: - return 0; + return ∅ } } -PRODUCTIONS(freestanding_argument_list) = -{ - {}, - {symbol_argument, symbol_freestanding_argument_list}, - {parse_token_type_end, symbol_freestanding_argument_list}, -}; RESOLVE(freestanding_argument_list) { + P empty = {}; + P arg = {symbol_argument, symbol_freestanding_argument_list}; + P semicolon = {parse_token_type_end, symbol_freestanding_argument_list}; + switch (token1.type) { case parse_token_type_string: - return 1; + return &arg; case parse_token_type_end: - return 2; + return &semicolon; default: - return 0; + return ∅ } } +RESOLVE_ONLY(block_statement) = {symbol_block_header, symbol_job_list, symbol_end_command, symbol_arguments_or_redirections_list}; -PRODUCTIONS(block_statement) = -{ - {symbol_block_header, symbol_job_list, symbol_end_command, 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) { + P forh = {symbol_for_header}; + P whileh = {symbol_while_header}; + P funch = {symbol_function_header}; + P beginh = {symbol_begin_header}; + switch (token1.keyword) { case parse_keyword_for: - return 0; + return &forh; case parse_keyword_while: - return 1; + return &whileh; case parse_keyword_function: - return 2; + return &funch; case parse_keyword_begin: - return 3; + return &beginh; default: return NO_PRODUCTION; } } -PRODUCTIONS(for_header) = -{ - {KEYWORD(parse_keyword_for), parse_token_type_string, KEYWORD - (parse_keyword_in), symbol_argument_list, parse_token_type_end} -}; -RESOLVE_ONLY(for_header) - -PRODUCTIONS(while_header) = -{ - {KEYWORD(parse_keyword_while), symbol_job, parse_token_type_end} -}; -RESOLVE_ONLY(while_header) - -PRODUCTIONS(begin_header) = -{ - {KEYWORD(parse_keyword_begin)} -}; -RESOLVE_ONLY(begin_header) - -PRODUCTIONS(function_header) = -{ - {KEYWORD(parse_keyword_function), symbol_argument, symbol_argument_list, parse_token_type_end} -}; -RESOLVE_ONLY(function_header) +RESOLVE_ONLY(for_header) = {KEYWORD(parse_keyword_for), parse_token_type_string, KEYWORD + (parse_keyword_in), symbol_argument_list, parse_token_type_end}; +RESOLVE_ONLY(while_header) = {KEYWORD(parse_keyword_while), symbol_job, parse_token_type_end}; +RESOLVE_ONLY(begin_header) = {KEYWORD(parse_keyword_begin)}; +RESOLVE_ONLY(function_header) = {KEYWORD(parse_keyword_function), symbol_argument, symbol_argument_list, parse_token_type_end}; /* 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) { + P ands = {KEYWORD(parse_keyword_and), symbol_statement}; + P ors = {KEYWORD(parse_keyword_or), symbol_statement}; + P nots = {KEYWORD(parse_keyword_not), symbol_statement}; + switch (token1.keyword) { case parse_keyword_and: - return 0; + *out_tag = parse_bool_and; + return &ands; case parse_keyword_or: - return 1; + *out_tag = parse_bool_or; + return &ors; case parse_keyword_not: - return 2; + *out_tag = parse_bool_not; + return ¬s; default: return NO_PRODUCTION; } } -PRODUCTIONS(decorated_statement) = -{ - {symbol_plain_statement}, - {KEYWORD(parse_keyword_command), symbol_plain_statement}, - {KEYWORD(parse_keyword_builtin), symbol_plain_statement}, - {KEYWORD(parse_keyword_exec), symbol_plain_statement} -}; RESOLVE(decorated_statement) { + P plains = {symbol_plain_statement}; + P cmds = {KEYWORD(parse_keyword_command), symbol_plain_statement}; + P builtins = {KEYWORD(parse_keyword_builtin), symbol_plain_statement}; + P execs = {KEYWORD(parse_keyword_exec), symbol_plain_statement}; + /* If this is e.g. 'command --help' then the command is 'command' and not a decoration. If the second token is not a string, then this is a naked 'command' and we should execute it as undecorated. */ if (token2.type != parse_token_type_string || token2.has_dash_prefix) { - return 0; + return &plains; } switch (token1.keyword) { default: - return 0; + *out_tag = parse_statement_decoration_none; + return &plains; case parse_keyword_command: - return 1; + *out_tag = parse_statement_decoration_command; + return &cmds; case parse_keyword_builtin: - return 2; + *out_tag = parse_statement_decoration_builtin; + return &builtins; case parse_keyword_exec: - return 3; + *out_tag = parse_statement_decoration_exec; + return &execs; } } -PRODUCTIONS(plain_statement) = -{ - {parse_token_type_string, symbol_arguments_or_redirections_list} -}; -RESOLVE_ONLY(plain_statement) +RESOLVE_ONLY(plain_statement) = {parse_token_type_string, symbol_arguments_or_redirections_list}; -PRODUCTIONS(arguments_or_redirections_list) = -{ - {}, - {symbol_argument_or_redirection, symbol_arguments_or_redirections_list} -}; RESOLVE(arguments_or_redirections_list) { + P empty = {}; + P value = {symbol_argument_or_redirection, symbol_arguments_or_redirections_list}; switch (token1.type) { case parse_token_type_string: case parse_token_type_redirection: - return 1; + return &value; default: - return 0; + return ∅ } } -PRODUCTIONS(argument_or_redirection) = -{ - {symbol_argument}, - {symbol_redirection} -}; RESOLVE(argument_or_redirection) { + P arg = {symbol_argument}; + P redir = {symbol_redirection}; switch (token1.type) { case parse_token_type_string: - return 0; + return &arg; case parse_token_type_redirection: - return 1; + return &redir; default: return NO_PRODUCTION; } } -PRODUCTIONS(argument) = -{ - {parse_token_type_string} -}; -RESOLVE_ONLY(argument) - -PRODUCTIONS(redirection) = -{ - {parse_token_type_redirection, parse_token_type_string} -}; -RESOLVE_ONLY(redirection) - -PRODUCTIONS(optional_background) = -{ - {}, - { parse_token_type_background } -}; +RESOLVE_ONLY(argument) = {parse_token_type_string}; +RESOLVE_ONLY(redirection) = {parse_token_type_redirection, parse_token_type_string}; RESOLVE(optional_background) { + P empty = {}; + P background = { parse_token_type_background }; switch (token1.type) { case parse_token_type_background: - return 1; + *out_tag = parse_background; + return &background; default: - return 0; + *out_tag = parse_no_background; + return ∅ } } -PRODUCTIONS(end_command) = -{ - {KEYWORD(parse_keyword_end)} -}; -RESOLVE_ONLY(end_command) +RESOLVE_ONLY(end_command) = {KEYWORD(parse_keyword_end)}; -#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, const parse_token_t &input1, const parse_token_t &input2, production_option_idx_t *out_which_production, wcstring *out_error_text) +#define TEST(sym) case (symbol_##sym): resolver = resolve_ ## sym ; break; +const production_t *parse_productions::production_for_token(parse_token_type_t node_type, const parse_token_t &input1, const parse_token_t &input2, parse_node_tag_t *out_tag) { const bool log_it = false; if (log_it) @@ -490,9 +389,8 @@ const production_t *parse_productions::production_for_token(parse_token_type_t n fprintf(stderr, "Resolving production for %ls with input token <%ls>\n", token_type_description(node_type).c_str(), input1.describe().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)(const parse_token_t &input1, const parse_token_t &input2) = NULL; + /* Fetch the function to resolve the list of productions */ + const production_t * (*resolver)(const parse_token_t &input1, const parse_token_t &input2, parse_node_tag_t *out_tag) = NULL; switch (node_type) { TEST(job_list) @@ -548,32 +446,17 @@ const production_t *parse_productions::production_for_token(parse_token_type_t n break; } - PARSE_ASSERT(production_list != NULL); PARSE_ASSERT(resolver != NULL); - const production_t *result = NULL; - production_option_idx_t which = resolver(input1, input2); - - if (log_it) - { - fprintf(stderr, "\tresolved to %u\n", (unsigned)which); - } - - - if (which == NO_PRODUCTION) + const production_t *result = resolver(input1, input2, out_tag); + if (result == NULL) { if (log_it) { fprintf(stderr, "Node type '%ls' has no production for input '%ls' (in %s)\n", token_type_description(node_type).c_str(), input1.describe().c_str(), __FUNCTION__); } - result = NULL; } - else - { - PARSE_ASSERT(production_is_valid(*production_list, which)); - result = &((*production_list)[which]); - } - *out_which_production = which; + return result; } |