Re: Another approach to lambdas

From: (Stefan Ram)
5 Jul 2014 21:36:02 GMT
Sebastian <> writes:

Yes. I specifically meant the syntax. Java 8 lambda syntax is reasonably
OK, but I wish they would have entirely dispensed with the need to
explicitly refer to the single method in a functional interface.
sumList.apply(map(x -> sumList.apply(x), matrix)); (*)
sumList(map(x -> sumList(x), matrix)); (**)
sumList is something like
Function<List<Integer>, Integer> sumList = x -> foldr((a,b)->a+b, 0, x);
(*) is actual Java 8 syntax, but I wish it were (**). I even guess that
would have been possible with a bit of compiler magic.

public class Main
{ public static void main( final java.lang.String args[] )
  { final java.util.List< java.lang.Integer >list = java.util.Arrays.asList( 1, 2, 3 );
    java.lang.System.out.println( 0,( x, y )-> x + y )); }}


public class Main
{ public static void main( final java.lang.String args[] )
  { final java.util.List< java.math.BigDecimal >list
    = java.util.Arrays.asList
    ( new java.math.BigDecimal( "3" ),
      new java.math.BigDecimal( "4" ),
      new java.math.BigDecimal( "5" ) );
      ( new java.math.BigDecimal( "0" ),
        java.math.BigDecimal::add )); }}


  C++, Java, Perl, and JavaScript took their common syntax from C.
  That's nice: one does not have to always learn a new syntax.

  But C did not have function literals, now every derived
  language started to invent its own syntax!


, C++:

, Perl 6:

, and Java:

  . That's sad, because now every of those languages has a
  different syntax for essentially the same thing. I like
  C++'s best, since it is the most unobtrusive! I wonder why
  the Java owners did not just copy it. After all, in the 90s
  Java was advertised as a language that is easy to learn for
  C++ programmers.

  Church's lambda expressions were called ?lambda expressions?
  because they contained a literal greek lambda letter. Java's
  ?()->{}? is not a ?lambda expression?, it's an arrow expression!

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