Parentheses?

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Tyler

Joined: 19 Nov 2009
Posts: 1215
Location: NC, USA

Tyler 07 May 2010, 22:05

baldr used parentheses in a way I've never seen done in Fasm here. What do they do? I've read the macro section of Fasm's manual multiple times and don't remember ever seeing ()s used for anything other than arithmetic.

07 May 2010, 22:05

mindcooler

Joined: 01 Dec 2009
Posts: 423
Location: Västerås, Sweden

mindcooler 07 May 2010, 23:12

My guess is they are just matched.

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07 May 2010, 23:12

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 08 May 2010, 04:46

Tyler,

mindcooler is right; match is powerful. For preprocessor, most of the input is just a stream of tokens (until they get handled).

It's easy to enhance macro with arguments syntax (but hard to invent clever one). Wink

08 May 2010, 04:46

Tyler

Joined: 19 Nov 2009
Posts: 1215
Location: NC, USA

Tyler 08 May 2010, 12:28

Oh, I don't get match anyway, that's probably why I didn't notice it.

How does it work, is it like if or something?

08 May 2010, 12:28

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 08 May 2010, 13:22

Tyler,

It performs attempt to match left and right sides of comma-separated pair. If they've matched, body is expanded, replacing tokens from left side with their matching counterparts from right side.

Code:

match 0, 1 { db 0 }

This code performs as follows:

«0» token is matched with «1» token;
macro body is expanded, replacing «0» with «1»
result is «db 1».

To protect tokens from replacement and match them literally, you must prepend them with «=»:

Code:

match =0, 1 { db 0 }

This code fails to match literal «0» token with «1» token, thus macro body doesn't get expanded.

Back to the topic:

Code:

match .name(.count), MessageBoxTimeoutW(6) { db .count, `.name }

08 May 2010, 13:22

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