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The "fact(match)" is very strange. In Haskell you have "lambda-case" and in Ocaml you have "fun" as syntaxes to define lambdas that pattern-match on the argumen

by ufo 12y ago

The "fact(match)" is very strange. In Haskell you have "lambda-case" and in Ocaml you have "fun" as syntaxes to define lambdas that pattern-match on the argument. That said, I really like the inclusion of async and a DSL for documents. These two are things that benefit a lot from having language support.

breuleux 12y ago
"fact(match)" is just making use of a generic feature: the "match" keyword in a pattern dictates that the body defines a sequence of sub-patterns to match at that position. An argument uses pattern syntax, so it works there, but it works in other situations, for example this contrived example: f(x, y) = match x: {m, n} -> match m: <= 0 -> n + y else -> m + n + y n -> n + y Can be rewritten: f(match x, y) = {match m, n} -> <= 0 -> n + y else -> m + n + y n -> n + y So you can match hierarchically like that (sorry if the example is strange, it's not supposed to mean anything).
- ufo 12y ago
  Is there any other language that does this? For me the second example doesn't look better than the first one.
  - breuleux 12y ago
    I haven't seen the feature elsewhere. The second example looks better to me (syntax highlighting helps) and reduces redundancy and indent, but I guess views may vary on this. Good to know!
    - ufo 12y ago
      If your goal is to reduce redundancy than I think a "lambda-case" syntax might be a better fit. As a bonus it also lets you use this feature on anonymous functions! https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/syntax-extns.html#lambda-case https://downloads.haskell.org/~ghc/latest/docs/html/users_gu... http://stackoverflow.com/questions/1604270/what-is-the-different-between-fun-and-function-keywords http://stackoverflow.com/questions/1604270/what-is-the-diffe...
      - breuleux 12y ago
        There already is a "lambda-case" syntax. "fact(match) = ..." is sugar for "fact = match -> ...". If one works, then so does the other. Personally I much prefer the way I do it, because it is more powerful, works in more places, and requires no new syntactic forms.
  - adrusi 12y ago
    I haven't seen this specifically, but I have seen other languages move common top level behaviors within functions into parameter lists. Ruby, dart, coffescript allow setting of instance variables from the parameter list: class Example constructor: (@name) -> # do stuff class Example constructor: (name) -> @name = name # do stuff Jonathan Blow's language allows the `using` keyword in parameter list, which desugars in much the same way. I'm personally not a big fan of using this technique for pattern matching, but its better than requiring explicit match blocks everywhere (like Scala and rust).

by ufo 12y ago

breuleux 12y ago

"fact(match)" is just making use of a generic feature: the "match" keyword in a pattern dictates that the body defines a sequence of sub-patterns to match at that position. An argument uses pattern syntax, so it works there, but it works in other situations, for example this contrived example: f(x, y) = match x: {m, n} -> match m: <= 0 -> n + y else -> m + n + y n -> n + y Can be rewritten: f(match x, y) = {match m, n} -> <= 0 -> n + y else -> m + n + y n -> n + y So you can match hierarchically like that (sorry if the example is strange, it's not supposed to mean anything).

ufo 12y ago
Is there any other language that does this? For me the second example doesn't look better than the first one.
- breuleux 12y ago
  I haven't seen the feature elsewhere. The second example looks better to me (syntax highlighting helps) and reduces redundancy and indent, but I guess views may vary on this. Good to know!
  - ufo 12y ago
    If your goal is to reduce redundancy than I think a "lambda-case" syntax might be a better fit. As a bonus it also lets you use this feature on anonymous functions! https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/syntax-extns.html#lambda-case https://downloads.haskell.org/~ghc/latest/docs/html/users_gu... http://stackoverflow.com/questions/1604270/what-is-the-different-between-fun-and-function-keywords http://stackoverflow.com/questions/1604270/what-is-the-diffe...
    - breuleux 12y ago
      There already is a "lambda-case" syntax. "fact(match) = ..." is sugar for "fact = match -> ...". If one works, then so does the other. Personally I much prefer the way I do it, because it is more powerful, works in more places, and requires no new syntactic forms.
- adrusi 12y ago
  I haven't seen this specifically, but I have seen other languages move common top level behaviors within functions into parameter lists. Ruby, dart, coffescript allow setting of instance variables from the parameter list: class Example constructor: (@name) -> # do stuff class Example constructor: (name) -> @name = name # do stuff Jonathan Blow's language allows the `using` keyword in parameter list, which desugars in much the same way. I'm personally not a big fan of using this technique for pattern matching, but its better than requiring explicit match blocks everywhere (like Scala and rust).