3 ms·

Honestly I'd rather use goto than have fallthrough by default in C. Or even better, a Fallthrough keyword as in GO.

codr7 7y ago
Wow, had no idea about fallthrough in Go and I've written plenty. Thanks. That's a seriously ugly solution, but I guess that could be considered a good thing.
b2gills 7y ago
Perl6 has a fallthrough keyword named `proceed`. It also has a keyword named `succeed` which is the default for `when` blocks. given 1 { when Int { say 'integer'; proceed } if 0 ≤ $_ ≤ 9 { say 'digit'; succeed } when 1 { say 'one'; proceed } } The above will print two lines `integer` and `digit`. It will not get a chance to run the second `when` block because of the `succeed` that gets run before it. If you want the `given` block to return a value, `succeed` can be given a value. my $result = do given $example { when 1 { 'one' } when 2 { succeed 'two' } # succeed is redundant here if $_ == 3 { succeed 'three' } # acts like a `when` block and returns "three" … } --- Perl6 is “supposed” to have a `goto` keyword, but nobody has implemented it. Mainly because of a lack of need. One of the few good uses of `goto` in a higher level language is to have a portion of a function always run at the function exit. Perl6 has `LEAVE`, `KEEP`, and `UNDO` which handles this nicely. sub foo (){ my $fh = open 'example.txt', :r; LEAVE $fh.close; # close $fh at scope exit … # use the opened file handle } Technically it would probably be better to have the `.close` be conditional on whether the $fh was successfully opened. sub foo (){ my $fh = open 'example.txt', :r; LEAVE with $fh {.close} without $fh {.throw}; # throw the error in `$fh` # (This isn't necessary, as it will get thrown as soon as you use it.) … # use the opened file handle }

Wow, had no idea about fallthrough in Go and I've written plenty. Thanks. That's a seriously ugly solution, but I guess that could be considered a good thing.

b2gills 7y ago

Perl6 has a fallthrough keyword named `proceed`. It also has a keyword named `succeed` which is the default for `when` blocks. given 1 { when Int { say 'integer'; proceed } if 0 ≤ $_ ≤ 9 { say 'digit'; succeed } when 1 { say 'one'; proceed } } The above will print two lines `integer` and `digit`. It will not get a chance to run the second `when` block because of the `succeed` that gets run before it. If you want the `given` block to return a value, `succeed` can be given a value. my $result = do given $example { when 1 { 'one' } when 2 { succeed 'two' } # succeed is redundant here if $_ == 3 { succeed 'three' } # acts like a `when` block and returns "three" … } --- Perl6 is “supposed” to have a `goto` keyword, but nobody has implemented it. Mainly because of a lack of need. One of the few good uses of `goto` in a higher level language is to have a portion of a function always run at the function exit. Perl6 has `LEAVE`, `KEEP`, and `UNDO` which handles this nicely. sub foo (){ my $fh = open 'example.txt', :r; LEAVE $fh.close; # close $fh at scope exit … # use the opened file handle } Technically it would probably be better to have the `.close` be conditional on whether the $fh was successfully opened. sub foo (){ my $fh = open 'example.txt', :r; LEAVE with $fh {.close} without $fh {.throw}; # throw the error in `$fh` # (This isn't necessary, as it will get thrown as soon as you use it.) … # use the opened file handle }