gram.y

postgresql8.3.4源码,开源数据库

						{ $$ = $1; }
				| stmt_open
						{ $$ = $1; }
				| stmt_fetch
						{ $$ = $1; }
				| stmt_move
						{ $$ = $1; }
				| stmt_close
						{ $$ = $1; }
				| stmt_null
						{ $$ = $1; }
				;

stmt_perform	: K_PERFORM lno expr_until_semi
					{
						PLpgSQL_stmt_perform *new;

						new = palloc0(sizeof(PLpgSQL_stmt_perform));
						new->cmd_type = PLPGSQL_STMT_PERFORM;
						new->lineno   = $2;
						new->expr  = $3;

						$$ = (PLpgSQL_stmt *)new;
					}
				;

stmt_assign		: assign_var lno K_ASSIGN expr_until_semi
					{
						PLpgSQL_stmt_assign *new;

						new = palloc0(sizeof(PLpgSQL_stmt_assign));
						new->cmd_type = PLPGSQL_STMT_ASSIGN;
						new->lineno   = $2;
						new->varno = $1;
						new->expr  = $4;

						$$ = (PLpgSQL_stmt *)new;
					}
				;

stmt_getdiag	: K_GET K_DIAGNOSTICS lno getdiag_list ';'
					{
						PLpgSQL_stmt_getdiag	 *new;

						new = palloc0(sizeof(PLpgSQL_stmt_getdiag));
						new->cmd_type = PLPGSQL_STMT_GETDIAG;
						new->lineno   = $3;
						new->diag_items  = $4;

						$$ = (PLpgSQL_stmt *)new;
					}
				;

getdiag_list : getdiag_list ',' getdiag_list_item
					{
						$$ = lappend($1, $3);
					}
				| getdiag_list_item
					{
						$$ = list_make1($1);
					}
				;

getdiag_list_item : getdiag_target K_ASSIGN getdiag_kind
					{
						PLpgSQL_diag_item *new;

						new = palloc(sizeof(PLpgSQL_diag_item));
						new->target = $1;
						new->kind = $3;

						$$ = new;
					}
				;

getdiag_kind : K_ROW_COUNT
					{
						$$ = PLPGSQL_GETDIAG_ROW_COUNT;
					}
				| K_RESULT_OID
					{
						$$ = PLPGSQL_GETDIAG_RESULT_OID;
					}
				;

getdiag_target	: T_SCALAR
					{
						check_assignable(yylval.scalar);
						$$ = yylval.scalar->dno;
					}
				;


assign_var		: T_SCALAR
					{
						check_assignable(yylval.scalar);
						$$ = yylval.scalar->dno;
					}
				| T_ROW
					{
						check_assignable((PLpgSQL_datum *) yylval.row);
						$$ = yylval.row->rowno;
					}
				| T_RECORD
					{
						check_assignable((PLpgSQL_datum *) yylval.rec);
						$$ = yylval.rec->recno;
					}
				| assign_var '[' expr_until_rightbracket
					{
						PLpgSQL_arrayelem	*new;

						new = palloc0(sizeof(PLpgSQL_arrayelem));
						new->dtype		= PLPGSQL_DTYPE_ARRAYELEM;
						new->subscript	= $3;
						new->arrayparentno = $1;

						plpgsql_adddatum((PLpgSQL_datum *)new);

						$$ = new->dno;
					}
				;

stmt_if			: K_IF lno expr_until_then proc_sect stmt_else K_END K_IF ';'
					{
						PLpgSQL_stmt_if *new;

						new = palloc0(sizeof(PLpgSQL_stmt_if));
						new->cmd_type	= PLPGSQL_STMT_IF;
						new->lineno		= $2;
						new->cond		= $3;
						new->true_body	= $4;
						new->false_body = $5;

						$$ = (PLpgSQL_stmt *)new;
					}
				;

stmt_else		:
					{
						$$ = NIL;
					}
				| K_ELSIF lno expr_until_then proc_sect stmt_else
					{
						/*
						 * Translate the structure:	   into:
						 *
						 * IF c1 THEN				   IF c1 THEN
						 *	 ...						   ...
						 * ELSIF c2 THEN			   ELSE
						 *								   IF c2 THEN
						 *	 ...							   ...
						 * ELSE							   ELSE
						 *	 ...							   ...
						 * END IF						   END IF
						 *							   END IF
						 */
						PLpgSQL_stmt_if *new_if;

						/* first create a new if-statement */
						new_if = palloc0(sizeof(PLpgSQL_stmt_if));
						new_if->cmd_type	= PLPGSQL_STMT_IF;
						new_if->lineno		= $2;
						new_if->cond		= $3;
						new_if->true_body	= $4;
						new_if->false_body	= $5;

						/* wrap the if-statement in a "container" list */
						$$ = list_make1(new_if);
					}

				| K_ELSE proc_sect
					{
						$$ = $2;
					}
				;

stmt_loop		: opt_block_label K_LOOP lno loop_body
					{
						PLpgSQL_stmt_loop *new;

						new = palloc0(sizeof(PLpgSQL_stmt_loop));
						new->cmd_type = PLPGSQL_STMT_LOOP;
						new->lineno   = $3;
						new->label	  = $1;
						new->body	  = $4.stmts;

						check_labels($1, $4.end_label);
						plpgsql_ns_pop();

						$$ = (PLpgSQL_stmt *)new;
					}
				;

stmt_while		: opt_block_label K_WHILE lno expr_until_loop loop_body
					{
						PLpgSQL_stmt_while *new;

						new = palloc0(sizeof(PLpgSQL_stmt_while));
						new->cmd_type = PLPGSQL_STMT_WHILE;
						new->lineno   = $3;
						new->label	  = $1;
						new->cond	  = $4;
						new->body	  = $5.stmts;

						check_labels($1, $5.end_label);
						plpgsql_ns_pop();

						$$ = (PLpgSQL_stmt *)new;
					}
				;

stmt_for		: opt_block_label K_FOR for_control loop_body
					{
						/* This runs after we've scanned the loop body */
						if ($3->cmd_type == PLPGSQL_STMT_FORI)
						{
							PLpgSQL_stmt_fori		*new;

							new = (PLpgSQL_stmt_fori *) $3;
							new->label	  = $1;
							new->body	  = $4.stmts;
							$$ = (PLpgSQL_stmt *) new;
						}
						else if ($3->cmd_type == PLPGSQL_STMT_FORS)
						{
							PLpgSQL_stmt_fors		*new;

							new = (PLpgSQL_stmt_fors *) $3;
							new->label	  = $1;
							new->body	  = $4.stmts;
							$$ = (PLpgSQL_stmt *) new;
						}
						else
						{
							PLpgSQL_stmt_dynfors	*new;

							Assert($3->cmd_type == PLPGSQL_STMT_DYNFORS);
							new = (PLpgSQL_stmt_dynfors *) $3;
							new->label	  = $1;
							new->body	  = $4.stmts;
							$$ = (PLpgSQL_stmt *) new;
						}

						check_labels($1, $4.end_label);
						/* close namespace started in opt_block_label */
						plpgsql_ns_pop();
					}
				;

for_control		:
				lno for_variable K_IN
					{
						int			tok = yylex();

						/* Simple case: EXECUTE is a dynamic FOR loop */
						if (tok == K_EXECUTE)
						{
							PLpgSQL_stmt_dynfors	*new;
							PLpgSQL_expr			*expr;

							expr = plpgsql_read_expression(K_LOOP, "LOOP");

							new = palloc0(sizeof(PLpgSQL_stmt_dynfors));
							new->cmd_type = PLPGSQL_STMT_DYNFORS;
							new->lineno   = $1;
							if ($2.rec)
							{
								new->rec = $2.rec;
								check_assignable((PLpgSQL_datum *) new->rec);
							}
							else if ($2.row)
							{
								new->row = $2.row;
								check_assignable((PLpgSQL_datum *) new->row);
							}
							else if ($2.scalar)
							{
								/* convert single scalar to list */
								new->row = make_scalar_list1($2.name, $2.scalar, $2.lineno);
								/* no need for check_assignable */
							}
							else
							{
								plpgsql_error_lineno = $2.lineno;
								yyerror("loop variable of loop over rows must be a record or row variable or list of scalar variables");
							}
							new->query = expr;

							$$ = (PLpgSQL_stmt *) new;
						}
						else
						{
							PLpgSQL_expr	*expr1;
							bool			 reverse = false;

							/*
							 * We have to distinguish between two
							 * alternatives: FOR var IN a .. b and FOR
							 * var IN query. Unfortunately this is
							 * tricky, since the query in the second
							 * form needn't start with a SELECT
							 * keyword.  We use the ugly hack of
							 * looking for two periods after the first
							 * token. We also check for the REVERSE
							 * keyword, which means it must be an
							 * integer loop.
							 */
							if (tok == K_REVERSE)
								reverse = true;
							else
								plpgsql_push_back_token(tok);

							/*
							 * Read tokens until we see either a ".."
							 * or a LOOP. The text we read may not
							 * necessarily be a well-formed SQL
							 * statement, so we need to invoke
							 * read_sql_construct directly.
							 */
							expr1 = read_sql_construct(K_DOTDOT,
													   K_LOOP,
													   "LOOP",
													   "SELECT ",
													   true,
													   false,
													   &tok);

							if (tok == K_DOTDOT)
							{
								/* Saw "..", so it must be an integer loop */
								PLpgSQL_expr		*expr2;
								PLpgSQL_expr		*expr_by;
								PLpgSQL_var			*fvar;
								PLpgSQL_stmt_fori	*new;
								char				*varname;

								/* Check first expression is well-formed */
								check_sql_expr(expr1->query);

								/* Read and check the second one */
								expr2 = read_sql_construct(K_LOOP,
														   K_BY,
														   "LOOP",
														   "SELECT ",
														   true,
														   true,
														   &tok);

								/* Get the BY clause if any */
								if (tok == K_BY)
									expr_by = plpgsql_read_expression(K_LOOP, "LOOP");
								else
									expr_by = NULL;

								/* Should have had a single variable name */
								plpgsql_error_lineno = $2.lineno;
								if ($2.scalar && $2.row)
									ereport(ERROR,
											(errcode(ERRCODE_SYNTAX_ERROR),
											 errmsg("integer FOR loop must have just one target variable")));

								/* create loop's private variable */
								plpgsql_convert_ident($2.name, &varname, 1);
								fvar = (PLpgSQL_var *)
									plpgsql_build_variable(varname,
														   $2.lineno,
														   plpgsql_build_datatype(INT4OID,
																				  -1),
														   true);

								new = palloc0(sizeof(PLpgSQL_stmt_fori));
								new->cmd_type = PLPGSQL_STMT_FORI;
								new->lineno   = $1;
								new->var	  = fvar;
								new->reverse  = reverse;
								new->lower	  = expr1;
								new->upper	  = expr2;
								new->step	  = expr_by;

								$$ = (PLpgSQL_stmt *) new;
							}
							else
							{
								/*
								 * No "..", so it must be a query loop. We've prefixed an
								 * extra SELECT to the query text, so we need to remove that
								 * before performing syntax checking.
								 */
								char				*tmp_query;
								PLpgSQL_stmt_fors	*new;

								if (reverse)
									yyerror("cannot specify REVERSE in query FOR loop");

								Assert(strncmp(expr1->query, "SELECT ", 7) == 0);
								tmp_query = pstrdup(expr1->query + 7);
								pfree(expr1->query);
								expr1->query = tmp_query;

								check_sql_expr(expr1->query);

								new = palloc0(sizeof(PLpgSQL_stmt_fors));
								new->cmd_type = PLPGSQL_STMT_FORS;
								new->lineno   = $1;
								if ($2.rec)
								{
									new->rec = $2.rec;
									check_assignable((PLpgSQL_datum *) new->rec);
								}
								else if ($2.row)
								{
									new->row = $2.row;
									check_assignable((PLpgSQL_datum *) new->row);
								}
								else if ($2.scalar)
								{
									/* convert single scalar to list */
									new->row = make_scalar_list1($2.name, $2.scalar, $2.lineno);
									/* no need for check_assignable */
								}
								else
								{
									plpgsql_error_lineno = $2.lineno;
									yyerror("loop variable of loop over rows must be a record or row variable or list of scalar variables");
								}

								new->query = expr1;
								$$ = (PLpgSQL_stmt *) new;
							}
						}
					}
				;

/*
 * Processing the for_variable is tricky because we don't yet know if the
 * FOR is an integer FOR loop or a loop over query results.  In the former
 * case, the variable is just a name that we must instantiate as a loop
 * local variable, regardless of any other definition it might have.
 * Therefore, we always save the actual identifier into $$.name where it
 * can be used for that case.  We also save the outer-variable definition,
 * if any, because that's what we need for the loop-over-query case.  Note
 * that we must NOT apply check_assignable() or any other semantic check
 * until we know what's what.
 *
 * However, if we see a comma-separated list of names, we know that it
 * can't be an integer FOR loop and so it's OK to check the variables
 * immediately.  In particular, for T_WORD followed by comma, we should
 * complain that the name is not known rather than say it's a syntax error.
 * Note that the non-error result of this case sets *both* $$.scalar and
 * $$.row; see the for_control production.
 */
for_variable	: T_SCALAR
					{
						int			tok;

						$$.name = pstrdup(yytext);
						$$.lineno  = plpgsql_scanner_lineno();
						$$.scalar = yylval.scalar;
						$$.rec = NULL;
						$$.row = NULL;
						/* check for comma-separated list */
						tok = yylex();
						plpgsql_push_back_token(tok);
						if (tok == ',')
							$$.row = read_into_scalar_list($$.name, $$.scalar);
					}
				| T_WORD
					{
						int			tok;

						$$.name = pstrdup(yytext);
						$$.lineno  = plpgsql_scanner_lineno();
						$$.scalar = NULL;
						$$.rec = NULL;
						$$.row = NULL;
						/* check for comma-separated list */
						tok = yylex();
						plpgsql_push_back_token(tok);
						if (tok == ',')
						{
							plpgsql_error_lineno = $$.lineno;
							ereport(ERROR,
									(errcode(ERRCODE_SYNTAX_ERROR),
									 errmsg("\"%s\" is not a scalar variable",
											$$.name)));
						}
					}
				| T_RECORD
					{
						$$.name = pstrdup(yytext);
						$$.lineno  = plpgsql_scanner_lineno();
						$$.scalar = NULL;
						$$.rec = yylval.rec;
						$$.row = NULL;
					}
				| T_ROW
					{
						$$.name = pstrdup(yytext);
						$$.lineno  = plpgsql_scanner_lineno();
						$$.scalar = NULL;
						$$.row = yylval.row;
						$$.rec = NULL;
					}
				;

stmt_exit		: exit_type lno opt_label opt_exitcond
					{
						PLpgSQL_stmt_exit *new;

						new = palloc0(sizeof(PLpgSQL_stmt_exit));
						new->cmd_type = PLPGSQL_STMT_EXIT;
						new->is_exit  = $1;
						new->lineno	  = $2;
						new->label	  = $3;
						new->cond	  = $4;

						$$ = (PLpgSQL_stmt *)new;
					}
				;

exit_type		: K_EXIT
					{
						$$ = true;
					}
				| K_CONTINUE
					{
						$$ = false;
					}
				;

stmt_return		: K_RETURN lno
					{
						int	tok;

						tok = yylex();
						if (tok == 0)
							yyerror("unexpected end of function definition");

						/*
						 * To avoid making NEXT and QUERY effectively be
						 * reserved words within plpgsql, recognize them
						 * via yytext.
						 */
						if (pg_strcasecmp(yytext, "next") == 0)
						{
							$$ = make_return_next_stmt($2);
						}
						else if (pg_strcasecmp(yytext, "query") == 0)
						{
							$$ = make_return_query_stmt($2);
						}
						else
						{
							plpgsql_push_back_token(tok);
							$$ = make_return_stmt($2);
						}
					}
				;

stmt_raise		: K_RAISE lno raise_level raise_msg
					{
						PLpgSQL_stmt_raise		*new;
						int	tok;

						new = palloc(sizeof(PLpgSQL_stmt_raise));

						new->cmd_type	= PLPGSQL_STMT_RAISE;
						new->lineno		= $2;
						new->elog_level = $3;
						new->message	= $4;
						new->params		= NIL;

						tok = yylex();

						/*
						 * We expect either a semi-colon, which
						 * indicates no parameters, or a comma that
						 * begins the list of parameter expressions
						 */
						if (tok != ',' && tok != ';')
							yyerror("syntax error");

						if (tok == ',')
						{
							PLpgSQL_expr *expr;
							int term;

							for (;;)
							{
								expr = read_sql_construct(',', ';', ", or ;",
														  "SELECT ",
														  true, true, &term);
								new->params = lappend(new->params, expr);
								if (term == ';')
									break;
							}
						}

						$$ = (PLpgSQL_stmt *)new;
					}
				;

raise_msg		: T_STRING
					{
						$$ = plpgsql_get_string_value();
					}
				;

raise_level		: K_EXCEPTION
					{
						$$ = ERROR;
					}
				| K_WARNING
					{
						$$ = WARNING;
					}
				| K_NOTICE
					{
						$$ = NOTICE;
					}
				| K_INFO
					{
						$$ = INFO;
					}
				| K_LOG
					{
						$$ = LOG;
					}
				| K_DEBUG
					{
						$$ = DEBUG1;
					}
				;