Comments on: Little-known Delphi grammar feature of the day: control-character syntax http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/ Life, .NET, and Cats Fri, 21 Nov 2008 06:18:25 +0000 http://wordpress.org/?v=2.5 By: Marcel Popescu http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5704 Marcel Popescu Tue, 11 Sep 2007 18:20:00 +0000 http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5704 I have actually used this syntax a lot. It makes sense to me to define <br> <br>const <br> CR = ^M; <br> LF = ^J; <br> <br>However, that doesn't say much :) Plus, with the general move towards Unicode, I really doubt anyone has any use for control characters. I have actually used this syntax a lot. It makes sense to me to define

const

CR = ^M;

LF = ^J;

However, that doesn’t say much :) Plus, with the general move towards Unicode, I really doubt anyone has any use for control characters.

]]> By: Joe White http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5703 Joe White Sat, 08 Sep 2007 10:51:00 +0000 http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5703 Sure, I *could* do it. What I can't do is handle it in the lexer, where it ideally would belong. Having to handle it in the parser (and generate a parse tree I'd be satisfied with) is a little more involved. <br> <br>Impossible? Certainly not. An hour or two of work, perhaps, to write the tests, make them pass, and make sure that every parse rule that used to look for TokenType.StringLiteral now looks for ParseRule.StringLiteral. <br> <br>But as I said, I've never actually seen this syntax in the wild... so I'm more interested in spending that hour or two on something useful. Sure, I *could* do it. What I can’t do is handle it in the lexer, where it ideally would belong. Having to handle it in the parser (and generate a parse tree I’d be satisfied with) is a little more involved.

Impossible? Certainly not. An hour or two of work, perhaps, to write the tests, make them pass, and make sure that every parse rule that used to look for TokenType.StringLiteral now looks for ParseRule.StringLiteral.

But as I said, I’ve never actually seen this syntax in the wild… so I’m more interested in spending that hour or two on something useful.

]]> By: Andreas Hausladen http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5702 Andreas Hausladen Thu, 06 Sep 2007 08:43:00 +0000 http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5702 But you wrote "I have no plans to support it in my parser". So you have a parser. But you wrote "I have no plans to support it in my parser". So you have a parser.

]]> By: Joe White http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5701 Joe White Wed, 05 Sep 2007 23:23:00 +0000 http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5701 Simple. The lexer doesn't know where the type blocks start and end. That's the parser's job. Simple. The lexer doesn’t know where the type blocks start and end. That’s the parser’s job.

]]> By: Andreas Hausladen http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5700 Andreas Hausladen Wed, 05 Sep 2007 14:59:00 +0000 http://blog.excastle.com/2007/09/05/little-known-delphi-grammar-feature-of-the-day-control-character-syntax/#comment-5700 - ^M as a char cannot appear after ":" <br>- ^M as a char can appear after ":=" where ^M as a pointer declaration cannot appear. <br>- ^M as a char cannot appear after "=" in the "type" block, whereas ^M as a pointer cannot appear after "=" outside of a "type" block. <br> <br>So where is the problem? - ^M as a char cannot appear after ":"

- ^M as a char can appear after ":=" where ^M as a pointer declaration cannot appear.

- ^M as a char cannot appear after "=" in the "type" block, whereas ^M as a pointer cannot appear after "=" outside of a "type" block.

So where is the problem?

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