<div dir="ltr">Hello all,<div><br></div><div>So I hit a road-block, the code:</div><div><br></div>> fun groups (): transaction page =<br>> m <- return ((Tregex.match'<br>> (concat (literal "a") (capture [#X] (literal "b"))) "ab")<div>> : option {Whole:counted_substring, Groups:{X:counted_substring}});<br>> case m of<br>> None => return <xml>Failed: mismatch!</xml><br>> | Some {Whole = whole, Groups = {X = {Start=s,Len=l}}} => return <xml>Success? Whole match: {[whole.Start]} + {[whole.Len]}, group is {[s]} + {[l]}</xml></div><div><br></div><div>Gives this error:</div><div><br></div><div><div>> .../test.ur:137:17: (to 139:7) Anonymous function remains at code generation</div><div>> Function:</div><div>> (fn _ : {} =></div><div>> (case UNBOUND_1 of</div><div>> None => write("Failed: mismatch!") |</div><div>> Some {Whole = whole, Groups = {X = {Start = s, Len = l}}} =></div><div>> (write("Success? Whole match: ");</div><div>> (FFI(Basis.htmlifyInt_w(whole.Start));</div><div>> (write(" + ");</div><div>> (FFI(Basis.htmlifyInt_w(whole.Len));</div><div>> (write(", group is ");</div><div>> (FFI(Basis.htmlifyInt_w(s));</div><div>> (write(" + "); FFI(Basis.htmlifyInt_w(l)))))))))))</div></div><div><br></div><div>To reproduce, you'll have to build urweb-regex (I've put some directions into README in my branch) and then do [cd tests && make all]</div><div><br></div><div>What can be done to avoid this issue? I tried to put type annotations, didn't work.</div></div><div class="gmail_extra"><br><div class="gmail_quote">2017-02-25 9:30 GMT+06:00 Artyom Shalkhakov <span dir="ltr"><<a href="mailto:artyom.shalkhakov@gmail.com" target="_blank">artyom.shalkhakov@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello all,<br>
<span class=""><br>
2017-02-23 21:55 GMT+06:00, Artyom Shalkhakov <<a href="mailto:artyom.shalkhakov@gmail.com">artyom.shalkhakov@gmail.com</a>>:<br>
> Hello Benjamin, Ziv,<br>
><br>
> I wrote a very rough approximation to the idea that Ziv proposed, here's<br>
> the code (currently, it does not do much):<br>
><br>
> <a href="https://github.com/ashalkhakov/urweb-regex/tree/typed-regex" rel="noreferrer" target="_blank">https://github.com/<wbr>ashalkhakov/urweb-regex/tree/<wbr>typed-regex</a><br>
><br>
> At first I was thinking that it would be better to introduce named groups,<br>
> but now I'm wondering how to handle positional groups, instead?<br>
><br>
> Tangentially, I also noticed that JS does not handle capture groups mixed<br>
> with repetition, e.g.<br>
><br>
> 'xabxabxab'.match(/(xab){3}/) // or with /(xab)*/<br>
><br>
> gives: ["xabxabxab", "xab"] (would it be worth it to try to rule out cases<br>
> like this statically? probably not?)<br>
><br>
<br>
</span>I guess I figured it out. The idea is to keep track of index for every<br>
group as well as the total count of groups in a regular expression.<br>
Then, when constructing a capture:<br>
<br>
> capture [#Name] E<br>
<br>
the group indexes in E get incremented by 1, a new group is added:<br>
{Name=0}, and the total count of groups is increased by 1.<br>
<br>
Similarly, when concatenating two expressions in<br>
<br>
> concat E1 E2<br>
<br>
the group indexes in E2 will all get incremented by N, where N is the<br>
count of groups of E1.<br>
<br>
I think it should work.<br>
<div class="HOEnZb"><div class="h5"><br>
><br>
> 2017-02-21 21:21 GMT+06:00 Benjamin Barenblat <<a href="mailto:bbaren@mit.edu">bbaren@mit.edu</a>>:<br>
><br>
>> On Mon, Feb 20, 2017 at 10:27 PM, Artyom Shalkhakov<br>
>> <<a href="mailto:artyom.shalkhakov@gmail.com">artyom.shalkhakov@gmail.com</a>> wrote:<br>
>> > Thank you for the pointer. I guess creating a new package that depends<br>
>> > on<br>
>> > urweb-regex is the way to go.<br>
>><br>
>> I’m also happy to merge changes to urweb-regex. I think a richly-typed<br>
>> API like the one you’re looking for would be quite valuable in the<br>
>> regex library.<br>
>><br>
>> ______________________________<wbr>_________________<br>
>> Ur mailing list<br>
>> <a href="mailto:Ur@impredicative.com">Ur@impredicative.com</a><br>
>> <a href="http://www.impredicative.com/cgi-bin/mailman/listinfo/ur" rel="noreferrer" target="_blank">http://www.impredicative.com/<wbr>cgi-bin/mailman/listinfo/ur</a><br>
>><br>
><br>
><br>
><br>
> --<br>
> Cheers,<br>
> Artyom Shalkhakov<br>
><br>
<br>
<br>
</div></div><span class="HOEnZb"><font color="#888888">--<br>
Cheers,<br>
Artyom Shalkhakov<br>
</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">Cheers,<br>Artyom Shalkhakov<br></div>
</div>