Re: enhance index builtin

[Gary V. Vaughan]

Hi Eric,

2009/2/10 Eric Blake <address@hidden>:
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> After my recent enhancement to substr, I noticed that index could also be
> made more useful if it took an optional starting index.  For example:
>
> index(`a(`b', `b')', `b', `4')
>
> is much different than
>
> index(eval(4 + substr(`a(`b', `b')', 4)))
>
> because of the interference caused by splitting nested quotes in substr.
>
>
> Technically, regexp could also be made more useful with a starting index,
> but I don't see how to add that in without breaking backwards
> compatibility (since regexp already has an optional argument that changes
> whether the result is the index where the match was found, vs. a
> substitution pattern using the matched pattern).

With the enhancements to argument parsing we discussed some time ago:

  regexp(`a(`b', `bb+')', `b+', ${offset=4})
    => 5
  regexp(`a(`b', `bb+')', `b+', `c', ${offset=4})
    => a(b, c+)
  regexp(`a(`b', `bb+')', `b+', ${resyntax=BASIC}, ${offset=4})
    => 6
  regexp(`a(`b', `bb+')', `b+', `c', ${resyntax=BASIC}, ${offset=4})
    => a(b, bc)

:)

Cheers
    Gary
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