Path: utzoo!attcan!uunet!hsi!stpstn!cox
From: cox@stpstn.UUCP (Brad Cox)
Newsgroups: comp.object
Subject: Re: code blocks (Was: Re: Objective-C review)
Message-ID: <5305@stpstn.UUCP>
Date: 30 Jun 90 19:22:23 GMT
References: <12396@june.cs.washington.edu> <1112@carol.fwi.uva.nl>
Reply-To: cox@stpstn.UUCP (Brad Cox)
Organization: Stepstone
Lines: 32

In article <1112@carol.fwi.uva.nl> delft@fwi.uva.nl (Andre van Delft) writes:
:John Maloney writes:
:How would code blocks in C look like?

No, a block (I prefer the word 'action') should be an *expression*, not 
a *statement*. The following syntax might suffice (assuming that C 
compound statement syntax can be parsed specially to denote block 
instantion when used as an expression).

	id aLocalVariable;
	aBlock = { action for subsequent invocation, which might and often will
		reference variables like aLocalVariable, formal arguments, etc. };
	[aMenu selectAction:aBlock];

or

	[aCollection do:{ id blockFormalArgument; | 
		[blockFormalArgument someOperation]; }];

or

	[ { action to run concurrently} fork];

or
	[ { action that might fail } with:{ action for handling exceptions}];

The main thing that makes blocks nontrivial is references from the block
into the instantation-site's local variables.
-- 

Brad Cox; cox@stepstone.com; CI$ 71230,647; 203 426 1875
The Stepstone Corporation; 75 Glen Road; Sandy Hook CT 06482