Mercurial > octave-dspies
diff libinterp/parse-tree/lex.ll @ 16149:49dfba4fd3c5
use pure parser and reentrant lexer interfaces
Making the Octave parser and lexer properly reentrant (and perhaps
eventually thread safe as well) is still a work in progress. With the
current set of changes the parser and lexer still use many global
variables, so these changes alone do NOT make the Octave parser
reentrant unless you take care to properly save and restore (typically
with an unwind_protect object) relevant global values before and after
calling the parser. Even if global variables are properly saved and
restored, the parser will NOT be thread safe.
* lex.ll: Use %option reentrant an %option bison-bridge.
(yylval): Delete macro.
(YY_EXTRA_TYPE, curr_lexer): New macros. Undefine curr_lexer
(YY_FATAL_ERROR): Update decl for reentrant scanner.
(lexical_feedback::reset): Update call to yyrestart for reentrant
scanner interface.
(lexical_feedback::fatal_error): Update call to yy_fatal_error for
reentrant scanner interface.
(lexical_feedback::text_yyinput): Update calls to yyinput and yyunput
for reentrant scanner interface.
(lexical_feedback::flex_yyleng): Use function interface to access
yyleng.
(lexical_feedback::flex_yytext): Use function interface to access
yytext.
(lexical_feedback::push_token, lexical_feedback::current_token):
Use function interface to access yylval.
* oct-parse.yy: Use %define api.pure, %parse-param, and %lex-param
options.
(curr_lexer): Define for syntax rules section.
(scanner): New macro.
* oct-parse.yy: Include oct-parse.h.
(octave_lex): Declare.
(yyerror): Update declaration for pure parser.
* parse.h (octave_lex): Delete decl.
* oct-parse.yy (octave_parser::run): Pass pointer to octave_parser
object to octave_parse.
* lex.ll (lexical_feedback::octave_read): Call fatal_error directly
instead of using YY_FATAL_ERROR.
* oct-parse.yy (parse_fcn_file): Pass line and column info for lexter
to gobble_leading_whitespace. Access prep_for_script_file,
prep_for_function_file, parsing_class_method, input_line_number, and
current_input_column through curr_parser.
* parse.h, oct-parse.yy (YY_BUFFER_STATE, create_buffer,
current_buffer, switch_to_buffer, delete_buffer, clear_all_buffers):
Delete.
* toplev.cc (main_loop): Don't create new buffer for lexer.
* input.cc (get_debug_input): Likewise.
* oct-parse.yy (eval_string, parse_fcn_file): Likewise.
* octave.cc (octave_initialize_interpreter): Likewise.
* input.cc (get_debug_input): Likewise.
* oct-parse.yy (eval_string, parse_fcn_file): Create parser as needed.
* octave.cc (octave_initialize_interpreter): Likewise.
* input.cc (get_debug_input): Likewise.
* input.cc (input_even_hook): Allow function to run even if currently
defining a function.
* lex.h, lex.ll (curr_lexer): Delete global variable.
* parse.h, oct-parse.yy (octave_parser::curr_lexer): New data member.
(octave_parser::octave_parser): Create lexer here.
(curr_parser): Delete global variable.
* toplev.cc (main_loop): Don't protect global curr_lexer and
curr_parser variables.
* oct-parse.yy (eval_string, parse_fcn_file): Likewise.
* input.cc (get_debug_input): Likewise.
* lex.h, lex.ll (curr_lexer): Delete global variable.
* parse.h, oct-parse.yy (CURR_LEXER): New temporary global.
(octave_parser::octave_parser): Set global CURR_LEXER here.
* toplev.cc (main_loop): Protect CURR_LEXER prior to constructing
new parser object.
* input.cc (get_debug_input): Likewise.
* oct-parse.yy (eval_string, parse_fcn_file): Likewise.
* lex.h, lex.ll (lexical_feedback::scanner): New data member.
(lexical_feedback::init): Create it. Call yylex_set_extra to store
pointer to lexical_feedback object in scanner data.
(lexical_feedback::~lexical_feedback): Delete it.
* lex.ll (YYG): New macro.
(lexical_feedback::reset, lexical_feedback::prep_for_script_file,
lexical_feedback::prep_for_function_file,
lexical_feedback::process_comment,
lexical_feedback::handle_close_bracket,
lexical_feedback::handle_identifier, lexical_feedback::lexer_debug):
Use it to access scanner data.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Wed, 27 Feb 2013 18:49:16 -0500 |
parents | 10abbc493f50 |
children | 891a2a4df71f |
line wrap: on
line diff
--- a/libinterp/parse-tree/lex.ll Wed Feb 27 18:21:50 2013 -0500 +++ b/libinterp/parse-tree/lex.ll Wed Feb 27 18:49:16 2013 -0500 @@ -20,8 +20,19 @@ */ +// We are using the pure parser interface and the reentrant lexer +// interface but the Octave parser and lexer are NOT properly +// reentrant because both still use many global variables. It should be +// safe to create a parser object and call it while anotehr parser +// object is active (to parse a callback function while the main +// interactive parser is waiting for input, for example) if you take +// care to properly save and restore (typically with an unwind_protect +// object) relevant global values before and after the nested call. + %option prefix = "octave_" %option noyywrap +%option reentrant +%option bison-bridge %top { #ifdef HAVE_CONFIG_H @@ -96,7 +107,8 @@ #error lex.l requires flex version 2.5.4 or later #endif -#define yylval octave_lval +#define YY_EXTRA_TYPE lexical_feedback * +#define curr_lexer yyextra // Arrange to get input via readline. @@ -107,14 +119,12 @@ result = curr_lexer->octave_read (buf, max_size) // Try to avoid crashing out completely on fatal scanner errors. -// The call to yy_fatal_error should never happen, but it avoids a -// 'static function defined but not used' warning from gcc. #ifdef YY_FATAL_ERROR #undef YY_FATAL_ERROR #endif #define YY_FATAL_ERROR(msg) \ - curr_lexer->fatal_error (msg) + (yyget_extra (yyscanner))->fatal_error (msg) #define DISPLAY_TOK_AND_RETURN(tok) \ do \ @@ -206,9 +216,6 @@ } \ while (0) -// The state of the lexer. -lexical_feedback *curr_lexer = 0; - static bool Vdisplay_tokens = false; static unsigned int Vtoken_count = 0; @@ -1117,70 +1124,9 @@ } } -// Tell us all what the current buffer is. - -YY_BUFFER_STATE -current_buffer (void) -{ - return YY_CURRENT_BUFFER; -} - -// Create a new buffer. - -YY_BUFFER_STATE -create_buffer (FILE *f) -{ - return yy_create_buffer (f, YY_BUF_SIZE); -} - -// Start reading a new buffer. - -void -switch_to_buffer (YY_BUFFER_STATE buf) -{ - yy_switch_to_buffer (buf); -} - -// Delete a buffer. - -void -delete_buffer (YY_BUFFER_STATE buf) -{ - yy_delete_buffer (buf); - - // Prevent invalid yyin from being used by yyrestart. - if (! current_buffer ()) - yyin = 0; -} - -// Delete all buffers from the stack. -void -clear_all_buffers (void) -{ - while (current_buffer ()) - octave_pop_buffer_state (); -} - void cleanup_parser (void) { - clear_all_buffers (); -} - -// Restore a buffer (for unwind-prot). - -void -restore_input_buffer (void *buf) -{ - switch_to_buffer (static_cast<YY_BUFFER_STATE> (buf)); -} - -// Delete a buffer (for unwind-prot). - -void -delete_input_buffer (void *buf) -{ - delete_buffer (static_cast<YY_BUFFER_STATE> (buf)); } // Return 1 if the given character matches any character in the given @@ -1366,11 +1312,38 @@ delete token_stack.top (); token_stack.pop (); } + + yylex_destroy (scanner); } void +lexical_feedback::init (void) +{ + // The closest paren, brace, or bracket nesting is not an object + // index. + looking_at_object_index.push_front (false); + + yylex_init (&scanner); + + // Make lexical_feedback object available through yyextra in + // flex-generated lexer. + yyset_extra (this, scanner); +} + +// Inside Flex-generated functions, yyg is the scanner cast to its real +// type. The BEGIN macro uses yyg and we want to use that in +// lexical_feedback member functions. If we could set the start state +// by calling a function instead of using the BEGIN macro, we could +// eliminate the OCTAVE_YYG macro. + +#define OCTAVE_YYG \ + struct yyguts_t *yyg = static_cast<struct yyguts_t*> (scanner) + +void lexical_feedback::reset (void) { + OCTAVE_YYG; + // Start off on the right foot. BEGIN (INITIAL); @@ -1389,7 +1362,7 @@ || reading_script_file || get_input_from_eval_string || input_from_startup_file)) - yyrestart (stdin); + yyrestart (stdin, scanner); // Clear the buffer for help text. while (! help_buf.empty ()) @@ -1399,12 +1372,16 @@ void lexical_feedback::prep_for_script_file (void) { + OCTAVE_YYG; + BEGIN (SCRIPT_FILE_BEGIN); } void lexical_feedback::prep_for_function_file (void) { + OCTAVE_YYG; + BEGIN (FUNCTION_FILE_BEGIN); } @@ -1466,7 +1443,7 @@ status = YY_NULL; if (! eof) - YY_FATAL_ERROR ("octave_read () in flex scanner failed"); + fatal_error ("octave_read () in flex scanner failed"); } return status; @@ -1475,13 +1452,13 @@ char * lexical_feedback::flex_yytext (void) { - return yytext; + return yyget_text (scanner); } int lexical_feedback::flex_yyleng (void) { - return yyleng; + return yyget_leng (scanner); } // GAG. @@ -1508,7 +1485,7 @@ int lexical_feedback::text_yyinput (void) { - int c = yyinput (); + int c = yyinput (scanner); if (lexer_debug_flag) { @@ -1521,7 +1498,7 @@ if (c == '\r') { - c = yyinput (); + c = yyinput (scanner); if (lexer_debug_flag) { @@ -1556,13 +1533,14 @@ if (c == '\n') input_line_number--; - yyunput (c, buf); + yyunput (c, buf, scanner); } void lexical_feedback::xunput (char c) { char *yytxt = flex_yytext (); + xunput (c, yytxt); } @@ -2077,6 +2055,8 @@ int lexical_feedback::process_comment (bool start_in_block, bool& eof) { + OCTAVE_YYG; + eof = false; std::string help_txt; @@ -2839,6 +2819,8 @@ int lexical_feedback::handle_close_bracket (bool spc_gobbled, int bracket_type) { + OCTAVE_YYG; + int retval = bracket_type; if (! nesting_level.none ()) @@ -3283,6 +3265,8 @@ int lexical_feedback::handle_identifier (void) { + OCTAVE_YYG; + bool at_bos = at_beginning_of_statement; char *yytxt = flex_yytext (); @@ -3518,14 +3502,16 @@ void lexical_feedback::push_token (token *tok) { - yylval.tok_val = tok; + YYSTYPE *lval = yyget_lval (scanner); + lval->tok_val = tok; token_stack.push (tok); } token * lexical_feedback::current_token (void) { - return yylval.tok_val; + YYSTYPE *lval = yyget_lval (scanner); + return lval->tok_val; } void @@ -3706,12 +3692,14 @@ OCTAVE_QUIT; - yy_fatal_error (msg); + yy_fatal_error (msg, scanner); } void lexical_feedback::lexer_debug (const char *pattern, const char *text) { + OCTAVE_YYG; + std::cerr << std::endl; display_state (YY_START);