range/3 efficiency

[fadado]

As defined in builtin.jq I find range/3 hard to understand and slow due the double test:

def range($init; $upto; $by):
    def _range:
        if ($by > 0 and . < $upto) or ($by < 0 and . > $upto) 
        then ., ((.+$by)|_range)
        else . end;
    if $by == 0 then $init else $init|_range end 
    | select(($by > 0 and . < $upto) or ($by < 0 and . > $upto))
;

I suggest this alternative implementation:

def range($init; $upto; $by):
    label $out
    | ($by>0) as $inc
    | ($by<0) as $dec
    | $init|recurse(.+$by)
    | if $inc and . < $upto or $dec and . > $upto # in range?
      then .
      else break$out
      end
;

In my tests it is 1/3 faster!

[itchyny]

The range/3 implementation has been improved by #1845 (fc6df0f).