Am I understanding you right, the prototyope mechanism of builtins like push can't distiguish between missing parameters and empty parameters. But some special functions like "print" and "splice" have a proper non-prototype-based interface? (*)

I'm not really missing that feature, it's just a meditation about design and orthogonality.

IMHO, it would be much easier to prog if perl had more axiomatic rules instead of a bunch of special exeptional cases. Something like "if the last obligatory list @ or scalar $ in a prototype is ommitted in the code, $_ will be included instead throwing an error".

Or as more flexible approach "you can use "@_" and "$_" in prototypes to flag parameters which default to $_ if missing" ²

anyway, perl6's solution to flag these functions with a trailing . and making them methodes of an invisible $_ seems reasonable! (eg  .print; .push @a;)

UPDATES:

(*) Must be! That's why prototype returns undef for print and split, showing they are not overridable!

  DB<10> use Data::Dumper


  DB<11> print Dumper prototype "CORE::split"
$VAR1 = undef;


  DB<12> print Dumper prototype "CORE::print"
$VAR1 = undef;


  DB<13> print Dumper prototype "CORE::push"
$VAR1 = '\\@@';
[download]

(²) But I don't know if it makes sense to push a global like $_ on the stack...

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