Cute. Reminds me of Perl 6 Feed operators. From S06:

Leftward feeds are a convenient way of explicitly indicating the typical right-to-left flow of data through a chain of operations:

    @oddsquares = map { $_**2 }, sort grep { $_ % 2 }, @nums;

    # more clearly written as...

    @oddsquares = map { $_**2 } <== sort <== grep { $_ % 2 } <== @nums
+;
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Rightward feeds are a convenient way of reversing the normal data flow in a chain of operations, to make it read left-to-right:

    @oddsquares =
            (@nums ==> grep { $_ % 2 } ==> sort ==> map { $_**2 });
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Note that the parens are necessary there due to precedence.