gram.y

PostgreSQL7.4.6 for Linux

					}
				;

execsql_start	: T_WORD
					{ $$ = strdup(yytext); }
				| T_ERROR
					{ $$ = strdup(yytext); }
				;

expr_until_semi :
					{ $$ = plpgsql_read_expression(';', ";"); }
				;

expr_until_rightbracket :
					{ $$ = plpgsql_read_expression(']', "]"); }
				;

expr_until_then :
					{ $$ = plpgsql_read_expression(K_THEN, "THEN"); }
				;

expr_until_loop :
					{ $$ = plpgsql_read_expression(K_LOOP, "LOOP"); }
				;

opt_label		:
					{
						plpgsql_ns_push(NULL);
						$$ = NULL;
					}
				| '<' '<' opt_lblname '>' '>'
					{
						plpgsql_ns_push($3);
						$$ = $3;
					}
				;

opt_exitlabel	:
					{ $$ = NULL; }
				| T_LABEL
					{ $$ = strdup(yytext); }
				;

opt_exitcond	: ';'
					{ $$ = NULL; }
				| K_WHEN expr_until_semi
					{ $$ = $2; }
				;

opt_lblname		: T_WORD
					{
						char	*name;

						plpgsql_convert_ident(yytext, &name, 1);
						$$ = strdup(name);
						pfree(name);
					}
				;

lno				:
					{
						$$ = plpgsql_error_lineno = plpgsql_scanner_lineno();
					}
				;

%%


PLpgSQL_expr *
plpgsql_read_expression(int until, const char *expected)
{
	return read_sql_construct(until, expected, true, "SELECT ");
}

static PLpgSQL_expr *
read_sql_stmt(const char *sqlstart)
{
	return read_sql_construct(';', ";", false, sqlstart);
}

static PLpgSQL_expr *
read_sql_construct(int until,
				   const char *expected,
				   bool isexpression,
				   const char *sqlstart)
{
	int					tok;
	int					lno;
	PLpgSQL_dstring		ds;
	int					parenlevel = 0;
	int					nparams = 0;
	int					params[1024];
	char				buf[32];
	PLpgSQL_expr		*expr;

	lno = plpgsql_scanner_lineno();
	plpgsql_dstring_init(&ds);
	plpgsql_dstring_append(&ds, (char *) sqlstart);

	for (;;)
	{
		tok = yylex();
		if (tok == until && parenlevel == 0)
			break;
		if (tok == '(' || tok == '[')
			parenlevel++;
		else if (tok == ')' || tok == ']')
		{
			parenlevel--;
			if (parenlevel < 0)
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("mismatched parentheses")));
		}
		/*
		 * End of function definition is an error, and we don't expect to
		 * hit a semicolon either (unless it's the until symbol, in which
		 * case we should have fallen out above).
		 */
		if (tok == 0 || tok == ';')
		{
			plpgsql_error_lineno = lno;
			if (parenlevel != 0)
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("mismatched parentheses")));
			if (isexpression)
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("missing \"%s\" at end of SQL expression",
								expected)));
			else
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("missing \"%s\" at end of SQL statement",
								expected)));
			break;
		}
		if (plpgsql_SpaceScanned)
			plpgsql_dstring_append(&ds, " ");
		switch (tok)
		{
			case T_VARIABLE:
				params[nparams] = yylval.variable->dno;
				snprintf(buf, sizeof(buf), " $%d ", ++nparams);
				plpgsql_dstring_append(&ds, buf);
				break;

			default:
				plpgsql_dstring_append(&ds, yytext);
				break;
		}
	}

	expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * nparams - sizeof(int));
	expr->dtype			= PLPGSQL_DTYPE_EXPR;
	expr->query			= strdup(plpgsql_dstring_get(&ds));
	expr->plan			= NULL;
	expr->nparams		= nparams;
	while(nparams-- > 0)
		expr->params[nparams] = params[nparams];
	plpgsql_dstring_free(&ds);

	return expr;
}

static PLpgSQL_type *
read_datatype(int tok)
{
	int					lno;
	PLpgSQL_dstring		ds;
	PLpgSQL_type		*result;
	bool				needspace = false;
	int					parenlevel = 0;

	lno = plpgsql_scanner_lineno();

	/* Often there will be a lookahead token, but if not, get one */
	if (tok == YYEMPTY)
		tok = yylex();

	if (tok == T_DTYPE)
	{
		/* lexer found word%TYPE and did its thing already */
		return yylval.dtype;
	}

	plpgsql_dstring_init(&ds);

	while (tok != ';')
	{
		if (tok == 0)
		{
			plpgsql_error_lineno = lno;
			if (parenlevel != 0)
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("mismatched parentheses")));
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("incomplete datatype declaration")));
		}
		/* Possible followers for datatype in a declaration */
		if (tok == K_NOT || tok == K_ASSIGN || tok == K_DEFAULT)
			break;
		/* Possible followers for datatype in a cursor_arg list */
		if ((tok == ',' || tok == ')') && parenlevel == 0)
			break;
		if (tok == '(')
			parenlevel++;
		else if (tok == ')')
			parenlevel--;
		if (needspace)
			plpgsql_dstring_append(&ds, " ");
		needspace = true;
		plpgsql_dstring_append(&ds, yytext);

		tok = yylex();
	}

	plpgsql_push_back_token(tok);

	plpgsql_error_lineno = lno;	/* in case of error in parse_datatype */

	result = plpgsql_parse_datatype(plpgsql_dstring_get(&ds));

	plpgsql_dstring_free(&ds);

	return result;
}


static PLpgSQL_stmt *
make_select_stmt(void)
{
	PLpgSQL_dstring		ds;
	int					nparams = 0;
	int					params[1024];
	char				buf[32];
	PLpgSQL_expr		*expr;
	PLpgSQL_row			*row = NULL;
	PLpgSQL_rec			*rec = NULL;
	int					tok = 0;
	int					have_nexttok = 0;
	int					have_into = 0;

	plpgsql_dstring_init(&ds);
	plpgsql_dstring_append(&ds, "SELECT ");

	while(1)
	{
		if (!have_nexttok)
			tok = yylex();
		have_nexttok = 0;
		if (tok == ';')
			break;
		if (tok == 0)
		{
			plpgsql_error_lineno = plpgsql_scanner_lineno();
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("unexpected end of function definition")));
		}
		if (tok == K_INTO)
		{
			if (have_into)
			{
				plpgsql_error_lineno = plpgsql_scanner_lineno();
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("INTO specified more than once")));
			}
			tok = yylex();
			switch (tok)
			{
				case T_ROW:
					row = yylval.row;
					have_into = 1;
					break;

				case T_RECORD:
					rec = yylval.rec;
					have_into = 1;
					break;

				case T_VARIABLE:
				{
					int				nfields = 1;
					char			*fieldnames[1024];
					int				varnos[1024];

					check_assignable(yylval.variable);
					fieldnames[0] = strdup(yytext);
					varnos[0]	  = yylval.variable->dno;

					while ((tok = yylex()) == ',')
					{
						tok = yylex();
						switch(tok)
						{
							case T_VARIABLE:
								check_assignable(yylval.variable);
								fieldnames[nfields] = strdup(yytext);
								varnos[nfields++]	= yylval.variable->dno;
								break;

							default:
								plpgsql_error_lineno = plpgsql_scanner_lineno();
								ereport(ERROR,
										(errcode(ERRCODE_SYNTAX_ERROR),
										 errmsg("\"%s\" is not a variable",
												yytext)));
						}
					}
					have_nexttok = 1;

					row = malloc(sizeof(PLpgSQL_row));
					row->dtype = PLPGSQL_DTYPE_ROW;
					row->refname = strdup("*internal*");
					row->lineno = plpgsql_scanner_lineno();
					row->rowtupdesc = NULL;
					row->nfields = nfields;
					row->fieldnames = malloc(sizeof(char *) * nfields);
					row->varnos = malloc(sizeof(int) * nfields);
					while (--nfields >= 0)
					{
						row->fieldnames[nfields] = fieldnames[nfields];
						row->varnos[nfields] = varnos[nfields];
					}

					plpgsql_adddatum((PLpgSQL_datum *)row);

					have_into = 1;
				}
				break;

				default:
					/* Treat the INTO as non-special */
					plpgsql_dstring_append(&ds, " INTO ");
					have_nexttok = 1;
					break;
			}
			continue;
		}

		if (plpgsql_SpaceScanned)
			plpgsql_dstring_append(&ds, " ");
		switch (tok)
		{
			case T_VARIABLE:
				params[nparams] = yylval.variable->dno;
				snprintf(buf, sizeof(buf), " $%d ", ++nparams);
				plpgsql_dstring_append(&ds, buf);
				break;

			default:
				plpgsql_dstring_append(&ds, yytext);
				break;
		}
	}

	expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * nparams - sizeof(int));
	expr->dtype			= PLPGSQL_DTYPE_EXPR;
	expr->query			= strdup(plpgsql_dstring_get(&ds));
	expr->plan			= NULL;
	expr->nparams		= nparams;
	while(nparams-- > 0)
		expr->params[nparams] = params[nparams];
	plpgsql_dstring_free(&ds);

	if (have_into)
	{
		PLpgSQL_stmt_select *select;

		select = malloc(sizeof(PLpgSQL_stmt_select));
		memset(select, 0, sizeof(PLpgSQL_stmt_select));
		select->cmd_type = PLPGSQL_STMT_SELECT;
		select->rec		 = rec;
		select->row		 = row;
		select->query	 = expr;

		return (PLpgSQL_stmt *)select;
	}
	else
	{
		PLpgSQL_stmt_execsql *execsql;

		execsql = malloc(sizeof(PLpgSQL_stmt_execsql));
		execsql->cmd_type = PLPGSQL_STMT_EXECSQL;
		execsql->sqlstmt  = expr;

		return (PLpgSQL_stmt *)execsql;
	}
}


static PLpgSQL_stmt *
make_fetch_stmt(void)
{
	int					tok;
	PLpgSQL_row		   *row = NULL;
	PLpgSQL_rec		   *rec = NULL;
	PLpgSQL_stmt_fetch *fetch;
	int					have_nexttok = 0;

	/* We have already parsed everything through the INTO keyword */

	tok = yylex();
	switch (tok)
	{
		case T_ROW:
			row = yylval.row;
			break;

		case T_RECORD:
			rec = yylval.rec;
			break;

		case T_VARIABLE:
			{
				int				nfields = 1;
				char			*fieldnames[1024];
				int				varnos[1024];

				check_assignable(yylval.variable);
				fieldnames[0] = strdup(yytext);
				varnos[0]	  = yylval.variable->dno;

				while ((tok = yylex()) == ',')
				{
					tok = yylex();
					switch(tok)
					{
						case T_VARIABLE:
							check_assignable(yylval.variable);
							fieldnames[nfields] = strdup(yytext);
							varnos[nfields++]	= yylval.variable->dno;
							break;

						default:
							plpgsql_error_lineno = plpgsql_scanner_lineno();
							ereport(ERROR,
									(errcode(ERRCODE_SYNTAX_ERROR),
									 errmsg("\"%s\" is not a variable",
											yytext)));
					}
				}
				have_nexttok = 1;

				row = malloc(sizeof(PLpgSQL_row));
				row->dtype = PLPGSQL_DTYPE_ROW;
				row->refname = strdup("*internal*");
				row->lineno = plpgsql_scanner_lineno();
				row->rowtupdesc = NULL;
				row->nfields = nfields;
				row->fieldnames = malloc(sizeof(char *) * nfields);
				row->varnos = malloc(sizeof(int) * nfields);
				while (--nfields >= 0)
				{
					row->fieldnames[nfields] = fieldnames[nfields];
					row->varnos[nfields] = varnos[nfields];
				}

				plpgsql_adddatum((PLpgSQL_datum *)row);
			}
			break;

		default:
			yyerror("syntax error");
	}

	if (!have_nexttok)
		tok = yylex();

	if (tok != ';')
		yyerror("syntax error");

	fetch = malloc(sizeof(PLpgSQL_stmt_select));
	memset(fetch, 0, sizeof(PLpgSQL_stmt_fetch));
	fetch->cmd_type = PLPGSQL_STMT_FETCH;
	fetch->rec		 = rec;
	fetch->row		 = row;

	return (PLpgSQL_stmt *)fetch;
}


static void
check_assignable(PLpgSQL_datum *datum)
{
	switch (datum->dtype)
	{
		case PLPGSQL_DTYPE_VAR:
			if (((PLpgSQL_var *) datum)->isconst)
			{
				plpgsql_error_lineno = plpgsql_scanner_lineno();
				ereport(ERROR,
						(errcode(ERRCODE_ERROR_IN_ASSIGNMENT),
						 errmsg("\"%s\" is declared CONSTANT",
								((PLpgSQL_var *) datum)->refname)));
			}
			break;
		case PLPGSQL_DTYPE_RECFIELD:
			/* always assignable? */
			break;
		case PLPGSQL_DTYPE_ARRAYELEM:
			/* always assignable? */
			break;
		case PLPGSQL_DTYPE_TRIGARG:
			yyerror("cannot assign to tg_argv");
			break;
		default:
			elog(ERROR, "unrecognized dtype: %d", datum->dtype);
			break;
	}
}

#include "pl_scan.c"