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Parsing a code block with EBNF expression

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Platinum Azure 2010-09-09 14:28:49

how would you define ANY_WITHIN_BLOCK?

nick2k3 2010-09-09 14:31:15

How are you defining ANY?

Platinum Azure 2010-09-09 14:31:31

ANY is the "jolly" token in CocoR: it matches every token.

nick2k3 2010-09-09 14:34:11

Sorry, I admit I'm not familiar with CocoR. I'm just writing a pseudocode CFG language. I was assuming you had defined {ANY} but if that's just a catch-all token, then that obviously complicates things. :-) (EDIT: Dang it. lol)

Platinum Azure 2010-09-09 14:35:01

I give you more details: I can define a character set in this fashion: letter ="A..Z" + "%>" so a letter may be any capital letter or the symbols within "". then I can define a token, which must be defined in terms of the character set. So a token, let's say, word should be defined as: word = letter{letter}

nick2k3 2010-09-09 14:35:27

Ah, and {WHATEVER} means zero or more WHATEVERs?

Platinum Azure 2010-09-09 14:42:07

Anyway, I guess my point is, I'd go for a more rigorous specification of EXACTLY what should go within a block, without relying on a catch-all token. Unless you can do a set difference (basically, ANY minus two tokens), you'll only end up having more than you want to in your code blocks.

Platinum Azure 2010-09-09 14:46:29

Platinum Azure 2010-09-09 14:49:27

Sorry for the late answer: you defined statements: statements statement| /* empty */ but a) how do you define 'statement'? the definition of method-block would be ok but in this way you are kind of parsing the codeblock too. btw I'll post my attributed grammar, maybe it would be more clear.

nick2k3 2010-09-10 09:01:48

I guess I left statement out of there because I figured that just comes down to how you'd define it (note that my specification is intentionally partial). "statement" is where I would break it down into things like, method-call, assignment, side-effect-expression, whatever. What I'm trying to show you is, don't rely on "any token" in the middle of a block-- be more specific; you want statements, so what constitutes a statement? If you say "assignment" as one possibility (which you probably should), what does that look like? That one would be `assignment: identifier "=" expression` or similar.

Platinum Azure 2010-09-10 13:56:55

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Parsing a code block with EBNF expression

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