octave-nkf: libinterp/parse-tree/lex.ll comparison

comparison libinterp/parse-tree/lex.ll @ 16224:4a848eb52de2

use stack for tracking lexer start states * lex.h (octave_lexer::start_state_stack): New member variable. (octave_lexer::push_start_state, octave_lexer::pop_start_state, octave_lexer::clear_start_state, octave_lexer::start_state, octave_lexer::display_start_state): New functions. * lex.ll (INPUT_FILE_START): Rename from INPUT_FILE_BEGIN. Use push_start_state and pop_start_state instead of switching flex start states directly with the flex BEGIN macro. (octave_lexer::init, octave_lexer::reset): Clear start state stack. (octave_lexer::prep_for_file, octave_lexer::process_comment, octave_lexer::handle_close_bracket): Don't use OCTAVE_YYG macro. (octave_lexer::display_start_state): Rename from display_state. Eliminate argument. Display current start state.

author	John W. Eaton <jwe@octave.org>
date	Fri, 08 Mar 2013 10:46:13 -0500
parents	e7ff32e7cf82
children	e19b1632d7c1

comparison

equal deleted inserted replaced

-:caf4f386aaab
+:4a848eb52de2
 }
 %s COMMAND_START
 %s MATRIX_START
-%x INPUT_FILE_BEGIN
+%x INPUT_FILE_START
 %{
 #include <cctype>
 #include <cstring>
 %{
 // Make script and function files start with a bogus token. This makes
 // the parser go down a special path.
 %}
-<INPUT_FILE_BEGIN>. {
+<INPUT_FILE_START>. {
-LEXER_DEBUG ("<INPUT_FILE_BEGIN>.");
+LEXER_DEBUG ("<INPUT_FILE_START>.");
-BEGIN (INITIAL);
 curr_lexer->xunput (yytext[0]);
 // May be reset later if we see "function" or "classdef" appears
 // as the first token.
 curr_lexer->reading_script_file = true;
+curr_lexer->pop_start_state ();
 DISPLAY_TOK_AND_RETURN (INPUT_FILE);
 }
 %{
 // Help and other command-style functions.
 %}
 <COMMAND_START>{NL} {
 LEXER_DEBUG ("<COMMAND_START>{NL}");
-BEGIN (INITIAL);
 curr_lexer->input_line_number++;
 curr_lexer->current_input_column = 1;
 curr_lexer->quote_is_transpose = false;
 curr_lexer->convert_spaces_to_comma = true;
 curr_lexer->looking_for_object_index = false;
 curr_lexer->at_beginning_of_statement = true;
+curr_lexer->pop_start_state ();
 COUNT_TOK_AND_RETURN ('\n');
 }
 <COMMAND_START>[\;\,] {
 LEXER_DEBUG ("<COMMAND_START>[\\;\\,]");
 curr_lexer->looking_for_object_index = false;
 curr_lexer->at_beginning_of_statement = true;
-BEGIN (INITIAL);
+curr_lexer->pop_start_state ();
 if (strcmp (yytext, ",") == 0)
 TOK_RETURN (',');
 else
 TOK_RETURN (';');
 curr_lexer->decrement_promptflag ();
 curr_lexer->eat_whitespace ();
 curr_lexer->bracketflag++;
-BEGIN (MATRIX_START);
+curr_lexer->push_start_state (MATRIX_START);
 COUNT_TOK_AND_RETURN ('[');
 }
 \] {
 LEXER_DEBUG ("\\]");
 curr_lexer->decrement_promptflag ();
 curr_lexer->eat_whitespace ();
 curr_lexer->braceflag++;
-BEGIN (MATRIX_START);
+curr_lexer->push_start_state (MATRIX_START);
 COUNT_TOK_AND_RETURN ('{');
 }
 "}" {
 LEXER_DEBUG ("}");
 yylex_init (&scanner);
 // Make octave_lexer object available through yyextra in
 // flex-generated lexer.
 yyset_extra (this, scanner);
+clear_start_state ();
 }
 // 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
+// type.  Some flex macros that we use in octave_lexer member functions
-// octave_lexer member functions.  If we could set the start state
+// (for example, BEGIN) use yyg.  If we could perform the actions of
-// by calling a function instead of using the BEGIN macro, we could
+// these macros with functions instead, we could eliminate the
-// eliminate the OCTAVE_YYG macro.
+// OCTAVE_YYG macro.
 #define OCTAVE_YYG \
 struct yyguts_t *yyg = static_cast<struct yyguts_t*> (scanner)
 void
 octave_lexer::reset (void)
 {
-OCTAVE_YYG;
 // Start off on the right foot.
-BEGIN (INITIAL);
+clear_start_state ();
 parser_symtab_context.clear ();
 // We do want a prompt by default.
 promptflag (1);
 }
 void
 octave_lexer::prep_for_file (void)
 {
-OCTAVE_YYG;
 reading_script_file = true;
-BEGIN (INPUT_FILE_BEGIN);
+push_start_state (INPUT_FILE_START);
 }
 int
 octave_lexer::read (char *buf, unsigned max_size)
 {
 }
 int
 octave_lexer::process_comment (bool start_in_block, bool& eof)
 {
-OCTAVE_YYG;
 eof = false;
 char *yytxt = flex_yytext ();
 flex_stream_reader flex_reader (this, yytxt);
 current_input_column = 1;
 quote_is_transpose = false;
 convert_spaces_to_comma = true;
 at_beginning_of_statement = true;
-if (YY_START == COMMAND_START)
+if (start_state () == COMMAND_START)
-BEGIN (INITIAL);
+pop_start_state ();
 if (nesting_level.none ())
 return '\n';
 else if (nesting_level.is_bracket_or_brace ())
 return ';';
 }
 int
 octave_lexer::handle_close_bracket (bool spc_gobbled, int bracket_type)
 {
-OCTAVE_YYG;
 int retval = bracket_type;
 if (! nesting_level.none ())
 {
 nesting_level.remove ();
 braceflag--;
 else
 panic_impossible ();
 }
-if (bracketflag == 0 && braceflag == 0)
+pop_start_state ();
-BEGIN (INITIAL);
 if (bracket_type == ']'
 && next_token_is_assign_op ()
 && ! looking_at_return_list)
 {
 if (! is_variable (tok))
 {
 if (at_bos && spc_gobbled && can_be_command (tok)
 && looks_like_command_arg ())
 {
-BEGIN (COMMAND_START);
+push_start_state (COMMAND_START);
 }
 else if (next_tok_is_eq
 || looking_at_decl_list
 || looking_at_return_list
 || (looking_at_parameter_list
 }
 break;
 }
 }
-static void
+void
-display_state (int state)
+octave_lexer::fatal_error (const char *msg)
+{
+error (msg);
+OCTAVE_QUIT;
+yy_fatal_error (msg, scanner);
+}
+void
+octave_lexer::lexer_debug (const char *pattern, const char *text)
+{
+std::cerr << std::endl;
+display_start_state ();
+std::cerr << "P: " << pattern << std::endl;
+std::cerr << "T: " << text << std::endl;
+}
+void
+octave_lexer::push_start_state (int state)
+{
+OCTAVE_YYG;
+start_state_stack.push (state);
+BEGIN (start_state ());
+}
+void
+octave_lexer::pop_start_state (void)
+{
+OCTAVE_YYG;
+start_state_stack.pop ();
+BEGIN (start_state ());
+}
+void
+octave_lexer::clear_start_state (void)
+{
+while (! start_state_stack.empty ())
+start_state_stack.pop ();
+push_start_state (INITIAL);
+}
+void
+octave_lexer::display_start_state (void) const
 {
 std::cerr << "S: ";
-switch (state)
+switch (start_state ())
 {
 case INITIAL:
 std::cerr << "INITIAL" << std::endl;
 break;
 case MATRIX_START:
 std::cerr << "MATRIX_START" << std::endl;
 break;
-case INPUT_FILE_BEGIN:
+case INPUT_FILE_START:
 std::cerr << "INPUT_FILE_BEGIN" << std::endl;
 break;
 default:
 std::cerr << "UNKNOWN START STATE!" << std::endl;
 break;
 }
 }
-void
-octave_lexer::fatal_error (const char *msg)
-{
-error (msg);
-OCTAVE_QUIT;
-yy_fatal_error (msg, scanner);
-}
-void
-octave_lexer::lexer_debug (const char *pattern, const char *text)
-{
-OCTAVE_YYG;
-std::cerr << std::endl;
-display_state (YY_START);
-std::cerr << "P: " << pattern << std::endl;
-std::cerr << "T: " << text << std::endl;
-}

Mercurial > octave-nkf

comparison libinterp/parse-tree/lex.ll @ 16224:4a848eb52de2