Streem – a new programming language from Matz

Post by ssmoot » Fri, Dec 12, 2014, 1:36 AM UTC

breuleux wrote: post #150

ssmoot wrote: post #126

Earlier quoted context omitted.

It doesn't. It's invalid code in most (all?) cases. scala> val f: Int => Int = _ - 1 f: Int => Int = scala> val ary = Array(1,2,3) ary: Array[Int] = Array(1, 2, 3) scala> ary.map(f(_ * 2)) :10: error: missing parameter type for expanded function ((x$1) => x$1.$times(2)) ary.map(f(_ * 2)) ^ You can't think of "_" like a placeholder. It's not. It's to lift an argument of a function. So simplify it: map in this context…

That's interesting, but you did not answer my question. I wanted to know how Scala determines where to insert =>. In my example, Scala interprets "ary.map(f(_ * 2))" as "ary.map(f(x => x * 2))" (both of these expressions yield the same error). If it interpreted it the other way, then the expression would work (using your definition of f). Perhaps a better example to use would have been: Array((_:Int) * 2) ==> (x:Int)…

  (_:Int) * 2

  Array.apply((_:Int) * 2)

Post by bjourne » Fri, Dec 12, 2014, 1:53 AM UTC

c3RlcGhlbnI_ wrote: post #42

I am glad that someone is working on a new stream processing language, it is a very interesting paradigm. However I hope that they provide some very robust tools for controlling input splitting. As I have spent too much time fighting with awk and wishing it was more flexible(it is frustrating always having exactly two levels of splitting with only matchers on the first and only inverse splitting on the second). As is…

    "~/yourfile.txt" utf8 file-contents 
    "\\w+" findall [ first second ] map [ 
        { 
            { "house" [ "house stuff" print ] } 
            { "car" [ "car" print ] } 
            [ "default stuff: %u\n" printf ] 
        } case 
    ] each

Post by rurounijones » Fri, Dec 12, 2014, 1:59 AM UTC

mostafah wrote: post #144

And... here’s an implementation: https://github.com/mattn/streeem Well, that was quick.

Post by candu » Fri, Dec 12, 2014, 2:22 AM UTC

c3RlcGhlbnI_ wrote: post #108

mackwic wrote: post #69

Earlier quoted context omitted.

Awesome ! Let's call it sed ! Reference: https://www.gnu.org/software/sed/manual/sed.html#Examples Sorry, I couldn't miss that one. :) Really, check the example. Sed is most powerful tool and can do astonishing work.

That manual is possibly the single most useful technical document that I have ever read. It has enabled me to write extremely powerful programs that no one I know can understand. It would however be nice to have a tool with similar power but simpler, more comprehensible syntax. One of the other commenters linked to an interesting document on sam, which has a better control flow but equally arcane syntax.

Post by lfender6445 » Fri, Dec 12, 2014, 2:25 AM UTC

chc wrote: post #71

pluma wrote: post #62

*Yukihiro Matsumoto, creator of Ruby I'm not sure everyone is familiar enough with Ruby to know who Matz is.

If they don't know who Matz is, are they likely to know who Yukihiro Matsumoto is? EDIT: Interesting fact: I believe this is now my most downvoted comment in five years on HN, at effectively -7. Never would have guessed. I'm not exactly sure what it says, but I thought it was an interesting data point.