> Hi
>
> Can an example of effective solutions?
> And why this decision is not effective?
>
> FieldGet (fieldnum ()) - a very cumbersome
> example:
> 1. ALIAS1-> & ( "NAME1") + = ALIAS2-> & ( "NAME2")
> 2. ALIAS1-> (FIELDPUT (FIELDNUM ( "NAME1"), FIELDGET (FIELDNUM (
> "NAME1") + ALIAS2-> (FIELDGET (FIELDNUM ( "NAME2"))))
> (easily be mistaken with brackets)
Macro expansion is always expensive, so it's
inefficient. This fact was realized by Clipper
5 dev team and that's why they introduced FIELDGET()
and friends.
In your case, there is seemingly a double
macro expansion done, finally to a codeblock,
which codeblock is then EVAL()-ed. This is
probably the slowest way a field value can be
extracted, since all operations are expensive:
macro eval (2x), codeblock creation, codeblock
evaluation.
This was suggested:
EVAL( &( "{|| field->&('" + name + "') }" ) )
->
RETURN FIELDGET( FIELDPOS( name ) )
To my eyes the second is much cleaner, simpler,
and much more typo-proof.
You can even create a simple macro:
#xtranslate FIELDGETBYNAME( <name> ) => FIELDGET( FIELDPOS( <name> ) )
and use:
RETURN FIELDGETBYNAME( name )
Brgds,
Viktor
_______________________________________________
Harbour mailing list (attachment size limit: 40KB)
[email protected]
http://lists.harbour-project.org/mailman/listinfo/harbour
