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About F# specification
f#

Hi, guys!

I hope that there are someone else who needs nice specification for F#, and that this topic can help.

I suggest to send a copy of each question from here to F# team.

So there's my question:

There is an alternative "long-ident pat-param? pat?" in grammar rule for pat (e.g. pattern I suppose). As I can see, pat-param does not differ from pat itself too much. First, I can't figure out what does it mean at all. Second, I'm working on LR parser and this rule conflicts with pat rule. I mean "IDENT null" is long-ident pat-param or long-ident pat?

Also, what does this pat-param mean at all?

.

This grammar rule is for active patterns (see section 7.1.5 of the spec). I believe that the answer to your "IDENT null" question is that it depends on the resolution of long-ident.

Consider these two active patterns:

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2
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let (|Test1|_|) o x =
  Some()

let (|Test2|_|) o =
  Some(o)

Then in Test1 null, null is a parameter to the Test1 active pattern, but Test2 null would be using null as a nested pattern.

-Keith

By on 8/10/2010 4:36 AM ()

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