>I have been experimenting with the Perl language recently and
>have found its regular expression syntax to be quite powerful and
>useful.  It seems to me that it would be useful to extend APL to
>support a version of regular expressions, perhaps as an extension
>to the "find" function.  It could be initially implemented as an
>auxiliary processor for experimentation.

>Given the generalized array features of second generation APLs
>it should be simple to apply regular expressions to numeric data
>as well as characters, e.g.  '['  12.3  '-'  100.5  ']+'  would match
>any sequence of one or more numbers x for which
>12.3 <= x <= 100.5.  Defining the result to be similar to that for
>"find" would allow this feature to be applied to arrays of
>arbitrary rank.

>Another possibility would be to have the regular expression handler
>take a two-element left argument, one of which was the regular
>expression itself, the other being a character representation of an
>APL expression to be applied to all matching sections of an array.
>That would be an interesting and powerful control structure.

>--- Brian