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A comment on Why Go Is Not Good. Parent comment

Re:Why Go Is Not Good by Peaker on Monday June 30, 2014 @10:14AM (#7965119)
Can you show some small example encoding of an AST in Go?
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Re:Why Go Is Not Good by stcredzero on Tuesday July 01, 2014 @04:57PM (#7973463)
The code for Twik has a simple AST in it. Of course, it's Lisp, so it's perhaps too simple.

http://blog.labix.org/2013/07/16/twik-a-tiny-language-for-go

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Re:Why Go Is Not Good by Peaker on Wednesday July 02, 2014 @01:53AM (#7975454)
The duplication there in each AST node kinda hurts the eyes :)

Also, the type-switch on interface {} is ugly.

Consider how an AST looks like in Haskell:

  data AST
    = LiteralInt Int
    | LiteralFloat Float
    | List [AST]
    ...
And then an eval looks like:

  case ast of
    LiteralInt int -> ...
    LiteralFloat float -> ...
    List nodes -> ...
and it is safe, rather than interface{}, you get the AST type and you get exhaustiveness checking that you covered all cases.

Also, if you add an annotation to each AST element (e.g: inferred types), you can very easily and safely map over them, etc.

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Re:Why Go Is Not Good by rogpeppe1 on Tuesday July 01, 2014 @10:04AM (#7970701)
http://golang.org/pkg/go/ast/

Well, not that small, i guess :-)

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