[#MDEV-19996] Bison grammar: turn singe-character operators into <kwd>

The rule remember_tok_start in the bison grammar may cause shift/reduce conflicts.
In order to fix ~~MDEV-19956~~ easier, lets get rid of remember_tok_start gradually.

As the first step let's change the token type for the following single-character operators from <NONE> to <kwd>.

%type <kwd>

        '-' '+' '*' '/' '%' '(' ')'

        ',' '!' '{' '}' '&' '|'

and replace remember_tok_start to token positions in with_list_element (to prove the conceipt), as follows:

@@ -15262,16 +15262,16 @@ with_list_element:

               MYSQL_YYABORT;

             Lex->with_column_list.empty();

-          AS '(' remember_tok_start query_expression remember_tok_end ')'

+          AS '(' query_expression ')'

             LEX *lex= thd->lex;

             const char *query_start= lex->sphead ? lex->sphead->m_tmp_query

                                                  : thd->query();

-            char *spec_start= $6 + 1;

-            With_element *elem= new With_element($1, *$2, $7);

+            const char *spec_start= $5.pos() + 1;

+            With_element *elem= new With_element($1, *$2, $6);

            if (elem == NULL || Lex->curr_with_clause->add_with_element(elem))

              MYSQL_YYABORT;

-            if (elem->set_unparsed_spec(thd, spec_start, $8,

+            if (elem->set_unparsed_spec(thd, spec_start, $7.pos(),

                                         spec_start - query_start))

               MYSQL_YYABORT;

Lex_input_stream::lex_one_token() will be changed to assign positions to the mentioned tokens, like this:

--- a/sql/sql_lex.cc

+++ b/sql/sql_lex.cc

@@ -1510,6 +1510,7 @@ int Lex_input_stream::lex_one_token(YYSTYPE *yylval, THD *thd)

     case MY_LEX_SKIP:                          // This should not happen

       if (c != ')')

         next_state= MY_LEX_START;         // Allow signed numbers

+      yylval->kwd.set_keyword(m_tok_start, 1);

       return((int) c);

     case MY_LEX_MINUS_OR_COMMENT:

Note, this change will not immediately resolve any conflicts.

Conflicts should be resolved in a separate patch by effectively replacing remember_tok_start to token positions in these grammar rules:

parenthesized_expr:

          remember_tok_start

          query_expression

            if (!($$= Lex->create_item_query_expression(thd, $1, $2)))

              MYSQL_YYABORT;

subselect:

          remember_tok_start

          query_expression

            if (!($$= Lex->parsed_subselect($2, $1)))

              YYABORT;

[MDEV-19996] Bison grammar: turn singe-character operators into <kwd> Created: 2019-07-09 Updated: 2019-07-10 Resolved: 2019-07-10
Status:	Closed
Project:	MariaDB Server
Component/s:	Parser
Fix Version/s:	10.4.7

[MDEV-19996] Bison grammar: turn singe-character operators into <kwd> Created: 2019-07-09 Updated: 2019-07-10 Resolved: 2019-07-10