Comments on: Parsing directives http://blog.excastle.com/2007/09/20/parsing-directives/ Life, .NET, and Cats Tue, 31 Aug 2010 13:47:10 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: crystalbit http://blog.excastle.com/2007/09/20/parsing-directives/comment-page-1/#comment-83025 crystalbit Wed, 16 Dec 2009 19:22:45 +0000 http://blog.excastle.com/2007/09/20/parsing-directives/#comment-83025 two years left, but it is still actual :) I did not even thought about such things with directives in delphi, I'm so happy to have found this post two years left, but it is still actual :) I did not even thought about such things with directives in delphi, I’m so happy to have found this post

]]> By: Fermando Madruga http://blog.excastle.com/2007/09/20/parsing-directives/comment-page-1/#comment-5712 Fermando Madruga Mon, 24 Sep 2007 07:13:00 +0000 http://blog.excastle.com/2007/09/20/parsing-directives/#comment-5712 Nice idea, nice work and nice findings! <br> <br>Imagine if Codegear/Borland had to follow someone else's standards instead of setting the rules! :) Nice idea, nice work and nice findings!

Imagine if Codegear/Borland had to follow someone else’s standards instead of setting the rules! :)

]]> By: Craig Stuntz http://blog.excastle.com/2007/09/20/parsing-directives/comment-page-1/#comment-5711 Craig Stuntz Fri, 21 Sep 2007 13:33:00 +0000 http://blog.excastle.com/2007/09/20/parsing-directives/#comment-5711 Then there's the directive default, which, IIRC, has a different meaning with and without the semicolon. With the semicolon it indicates the default indexer; without it's followed by the default value of the property. <br> <br>One of the C++ TeamB guys once asked me why directives were preceded by the line separator. I didn't know, so I directed him to Danny Thorpe, who was standing nearby. I don't recall Danny's precise answer, but I think it amounted to, "There's not really a good reason for it; it's just the way it is." <br> <br>Allen, I don't understand "in-keeping with the notion that the semi-colon was a terminator not a separator." In Pascal the semicolon is a (line/argument) separator, not a (line/argument) terminator. Moreover, semicolons have always appeared midline, as with separating multiple function arguments. Then there’s the directive default, which, IIRC, has a different meaning with and without the semicolon. With the semicolon it indicates the default indexer; without it’s followed by the default value of the property.

One of the C++ TeamB guys once asked me why directives were preceded by the line separator. I didn’t know, so I directed him to Danny Thorpe, who was standing nearby. I don’t recall Danny’s precise answer, but I think it amounted to, "There’s not really a good reason for it; it’s just the way it is."

Allen, I don’t understand "in-keeping with the notion that the semi-colon was a terminator not a separator." In Pascal the semicolon is a (line/argument) separator, not a (line/argument) terminator. Moreover, semicolons have always appeared midline, as with separating multiple function arguments.

]]> By: Allen Bauer http://blog.excastle.com/2007/09/20/parsing-directives/comment-page-1/#comment-5710 Allen Bauer Thu, 20 Sep 2007 17:56:00 +0000 http://blog.excastle.com/2007/09/20/parsing-directives/#comment-5710 There are several reasons for this apparent inconsistency. Originally, all directives *could not* have a semicolon between them. This was in-keeping with the notion that the semi-colon was a terminator not a separator. However, in practice, this was less than intuitive to explain or remember. So what this all means is that you cannot have a var block like this: <br> <br>var <br> Foo: procedure; <br> StdCall: Integer; <br> <br>Not likely to happen (who would name a variable StdCall?? However, syntactically it is possible). Had we enforced the "no semicolon" rule, then you *could* have a construct like above. <br> <br>Remember, directives are *not* reserved words in the same sense as "for" "case" "while." They're only semi-reserved based on their context. "requires" and "contains" are the same way. They're only reserved in the context of a file with a leading "package" clause. <br> <br>The whole notion of directives syntax was discussed at length internally. We were trying to be as "nice" as possible by limiting the breakage of existing code while making the syntax more "natural." <br> <br>Allen. <br> There are several reasons for this apparent inconsistency. Originally, all directives *could not* have a semicolon between them. This was in-keeping with the notion that the semi-colon was a terminator not a separator. However, in practice, this was less than intuitive to explain or remember. So what this all means is that you cannot have a var block like this:

var

Foo: procedure;

StdCall: Integer;

Not likely to happen (who would name a variable StdCall?? However, syntactically it is possible). Had we enforced the "no semicolon" rule, then you *could* have a construct like above.

Remember, directives are *not* reserved words in the same sense as "for" "case" "while." They’re only semi-reserved based on their context. "requires" and "contains" are the same way. They’re only reserved in the context of a file with a leading "package" clause.

The whole notion of directives syntax was discussed at length internally. We were trying to be as "nice" as possible by limiting the breakage of existing code while making the syntax more "natural."

Allen.

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