[ruby-core:60371] [ruby-trunk - Feature #8987] map/collect extension which handles arguments

Issue #8987 has been updated by Koichi Sasada.


 (2013/10/06 0:26), sawa (Tsuyoshi Sawada) wrote:
 >     [1, 2, 3, 4].map(&4.method(:+))
 >     # =3D> [5, 6, 7, 8]
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 Interesting.
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 If we use =CE=BB (alias of lambda=EF=BC=89, it is more short.
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     module Kernel
       alias =CE=BB lambda
     end
     p [1, 2, 3, 4].map(&4.method(:+)) #=3D> [5, 6, 7, 8]
     p [1, 2, 3, 4].map(&=CE=BB{|x| 4+x})  #=3D> [5, 6, 7, 8]
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 If we define =CE=BB as the following definition, more short code.
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     module Kernel
       def =CE=BB(a, sym)
         lambda{|x| a.send(sym, x)}
       end
     end
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     p [1, 2, 3, 4].map(&=CE=BB(4, :+))  #=3D> [5, 6, 7, 8]
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 A bit shorter version.
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     module Kernel
       def =CE=BB(expr)
         eval("lambda{|x| #{expr} x}")
       end
     end
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     p [1, 2, 3, 4].map(&=CE=BB("4+"))  #=3D> [5, 6, 7, 8]
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 If we have default parameter `_' (maybe matz doesn't like), we can make
 more short code.
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     p [1, 2, 3, 4].map(&=CE=BB{4+_})      #=3D> [5, 6, 7, 8]
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 Summary:
     p [1, 2, 3, 4].map(&4.method(:+)) #=3D> [5, 6, 7, 8]
     p [1, 2, 3, 4].map(&=CE=BB{|x| 4+x})  #=3D> [5, 6, 7, 8]
     p [1, 2, 3, 4].map(&=CE=BB(4, :+))    #=3D> [5, 6, 7, 8]
     p [1, 2, 3, 4].map(&=CE=BB("4+"))     #=3D> [5, 6, 7, 8]
     p [1, 2, 3, 4].map(&=CE=BB{4+_})      #=3D> [5, 6, 7, 8] (doesn't run)
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 --=20
 // SASADA Koichi at atdot dot net

----------------------------------------
Feature #8987: map/collect extension which handles arguments
https://bugs.ruby-lang.org/issues/8987#change-44850

* Author: So Wieso
* Status: Open
* Priority: Normal
* Assignee:=20
* Category: core
* Target version: current: 2.2.0
----------------------------------------
Please consider extending map/collect by allowing additional arguments to b=
e passed to proc, like:
A: [1,2,3,4].map :+, 4
and/or
B: [1,2,3,4].map 4, &:+

=3D> [5, 6, 7, 8]

Variant A is probably more readable. Variant B is more versatile (allows ar=
bitrary arguments to be passed to block).


---Files--------------------------------
mappi.rb (410 Bytes)


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http://bugs.ruby-lang.org/