in reply to Functional Composition

The same as this, but very, very slowly! 

c:\test>perl -E"say join'-',split'', reverse ucfirst 'hello';"
o-l-l-e-H

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Re^2: Functional Composition
by billh (Pilgrim) on Dec 17, 2009 at 21:38 UTC

    You're right of course, but I chose perl builtins to keep the example short. If you consider that each of those 'fn's could be arbitrarily complex and require braces around their arguments that would become

    perl -E"say(join('-', split('', reverse(ucfirst('hello')))))"

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    Plus I have to admit I kind of screwed up, "functional composition" really means "take two functions and produce a third", like

    compose(sub{ ucfirst $[0] }, sub { $_[0] . "\n" });

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    would return a function that would ucfirst its arg and append a newline, whereas my code invokes the functions directly. Still, it looks pretty.

    Bill H
    perl -e 'print sub { "Hello @{[shift->()]}!\n" }->(sub{"World"})'

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