Hi,
I want to learn, how the pl/plsql-parser/compiler works. Therefore I planned
to implement a simple ELSIF, like oracle does.
I added the following K_ELSIF branch to gram.y, in the hope that, when ELSIF
is parsed, simply another if-structure in inserted.
---------------------------------------------------------
stmt_else :
{
PLpgSQL_stmts *new;
new = malloc(sizeof(PLpgSQL_stmts));
memset(new, 0, sizeof(PLpgSQL_stmts));
$$ = new;
elog(NOTICE, "empty ELSE detected");
}
| K_ELSIF expr_until_then proc_sect stmt_else
{
PLpgSQL_stmt_if *new;
elog(NOTICE, "ELSIF detected");
new = malloc(sizeof(PLpgSQL_stmt_if));
memset(new, 0, sizeof(PLpgSQL_stmt_if));
new->cmd_type = PLPGSQL_STMT_IF;
// new->lineno = $2;
new->cond = $2;
new->true_body = $3;
new->false_body = $4;
$$ = (PLpgSQL_stmts *)new;
}
| K_ELSE proc_sect
{
$$ = $2;
elog(NOTICE, "ELSE detected (%s)",
strdup(yytext));
}
;
--------------------------------------------------------------
A testprocedure, which looks like that:
--------------------------------------------------------------
DECLARE
iPar1PI ALIAS FOR $1;
iTmp integer;
iResult varchar;
BEGIN
iTmp = iPar1PI;
raise notice '1.0';
if iTmp IS NULL then
raise notice '2.0';
iResult = 'Echt NULL';
else
if iTmp = 0 then
raise notice '2.1.0';
iResult = 'Null (0)';
elsif (iTmp < 0) THEN
raise notice '2.1.1';
iResult = 'Negativ';
elsif (iTmp > 0) THEN
raise notice '2.1.2';
iResult = 'Positiv';
else
raise notice '2.1.3';
iResult = 'Gibts nicht!';
end if;
end if;
raise notice '3.0';
return iResult;
END;
--------------------------------------------------------------
is dumped in this way ...
--------------------------------------------------------------
Execution tree of successfully compiled PL/pgSQL function kr_test:
Functions data area:
entry 0: VAR $1 type int4 (typoid 23) atttypmod -1
entry 1: VAR found type bool (typoid 16) atttypmod -1
entry 2: VAR itmp type int4 (typoid 23) atttypmod -1
entry 3: VAR iresult type varchar (typoid 1043) atttypmod -1
Functions statements:
8:BLOCK <<*unnamed*>>
10: ASSIGN var 2 := 'SELECT $1 {$1=0}'
12: RAISE ''1.0''
14: IF 'SELECT $1 IS NULL {$1=2}' THEN
15: RAISE ''2.0''
16: ASSIGN var 3 := 'SELECT 'Echt NULL''
ELSE
19: IF 'SELECT $1 = 0 {$1=2}' THEN
20: RAISE ''2.1.0''
21: ASSIGN var 3 := 'SELECT 'Null (0)''
ELSE
ENDIF
ENDIF
37: RAISE ''3.0''
39: RETURN 'SELECT $1 {$1=3}'
END -- *unnamed*
End of execution tree of function kr_test
--------------------------------------------------------------
So my question is: Why does my inserted
PLpgSQL_stmt_if *new;
is not executed, because I do it in the same way like stmt_if does?
Who can halp me (Maybe Jan??)
Regards, Klaus
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