Postgresql随手记（7）使用plpgsql解析stmt_execsql子树过程

proc_stmt		: pl_block ';'
						{ $$ = $1; }
				| stmt_assign
						{ $$ = $1; }
				| stmt_if
						{ $$ = $1; }
				| stmt_case
						{ $$ = $1; }
				| stmt_loop
						{ $$ = $1; }
				| stmt_while
						{ $$ = $1; }
				| stmt_for
						{ $$ = $1; }
				| stmt_foreach_a
						{ $$ = $1; }
				| stmt_exit
						{ $$ = $1; }
				| stmt_return
						{ $$ = $1; }
				| stmt_raise
						{ $$ = $1; }
				| stmt_assert
						{ $$ = $1; }
				| stmt_execsql
						{ $$ = $1; }

stmt_execsql	: K_IMPORT
					{
						$$ = make_execsql_stmt(K_IMPORT, @1);
					}
				| K_INSERT
					{
						$$ = make_execsql_stmt(K_INSERT, @1);
					}
				| T_WORD
					{
						int			tok;

						tok = yylex();
						plpgsql_push_back_token(tok);
						if (tok == '=' || tok == COLON_EQUALS || tok == '[')
							word_is_not_variable(&($1), @1);
						$$ = make_execsql_stmt(T_WORD, @1);
					}
				| T_CWORD
					{
						int			tok;

						tok = yylex();
						plpgsql_push_back_token(tok);
						if (tok == '=' || tok == COLON_EQUALS || tok == '[')
							cword_is_not_variable(&($1), @1);
						$$ = make_execsql_stmt(T_CWORD, @1);
					}
				;

$$
begin
    select (3+1) into vvv;      
    select 100 into v_int;
end;
$$;

stmt_execsql	: opt_stmt_label K_IMPORT
				...
				...
				| opt_stmt_label T_WORD
					{
						int			tok;

						tok = yylex();
						plpgsql_push_back_token(tok);
						if (tok == '=' || tok == COLON_EQUALS ||
							tok == '[' || tok == '.')
							word_is_not_variable(&($2), @2);
						$$ = make_execsql_stmt($1, T_WORD, @2);
					}
					...
					...

tok = 275                         T_WORD
for (;;)
	prev_tok = 275   tok = 40     (
	prev_tok = 40    tok = 266    ICONST
	prev_tok = 266   tok = 43     +
	prev_tok = 43    tok = 266    ICONST
	prev_tok = 266   tok = 41     )
	prev_tok = 41    tok = 334    K_INTO
	prev_tok = 334   tok = 59     ;

tok = 275                       T_WORD
for (;;)
	prev_tok = 275   tok = 40     (
	prev_tok = 40    tok = 266    ICONST            --> 3
	prev_tok = 266   tok = 43     +                 --> +
	prev_tok = 43    tok = 266    ICONST            --> 1
	prev_tok = 266   tok = 41     )
	prev_tok = 41    tok = 334    K_INTO            --> INTO
	  if (tok == K_INTO)
	    read_into_target(&target, &have_strict)
	      ...
	      tok = yylex() // 277    T_DATUM           --> vvv
	      read_into_scalar_list(NameOfDatum(&(yylval.wdatum)),yylval.wdatum.datum, yylloc);
	      
	prev_tok = 334   tok = 59     ;                 --> ;

tok = 275                      T_WORD
for (;;)
	prev_tok = 275   tok = 266   ICONST
	prev_tok = 266   tok = 334   K_INTO
	prev_tok = 334   tok = 59    ;