Optional parameters: Difference between revisions
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OCaml does not support optional positional parameters, because, since OCaml supports currying, it would conflict with partial applications, where you do not provide all the arguments to a function, and it results in a function which expects the remaining arguments. |
OCaml does not support optional positional parameters, because, since OCaml supports currying, it would conflict with partial applications, where you do not provide all the arguments to a function, and it results in a function which expects the remaining arguments. |
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=={{header|Perl}}== |
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This function expects its first argument to be a reference to an array of arrays. It interprets any remaining arguments as a hash of optional parameters. |
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<lang perl>sub sorttable |
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{my @table = @{shift()}; |
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my %opt = |
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(ordering => sub {$_[0] cmp $_[1]}, column => 0, reverse => 0, @_); |
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my $col = $opt{column}; |
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my @result = sort |
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{$opt{ordering}->($a->[$col], $b->[$col])} |
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@table; |
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return ($opt{reverse} ? [reverse @result] : \@result);}</lang> |
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An example of use: |
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<lang perl>my $a = [["a", "b", "c"], ["", "q", "z"], ["zap", "zip", "Zot"]]; |
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foreach (@{sorttable $a, column => 1, reverse => 1}) |
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{foreach (@$_) |
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{printf "%-5s", $_;} |
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print "\n";}</lang> |
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=={{header|Python}}== |
=={{header|Python}}== |
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