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2+2…

After a lovely time with mfix making cyclic data structures, so that Nat knows about its bits which are typed in terms of Nat, I then had a horrid time chasing down a peculiar bug. It turns out that

(t :->> w) @@ e = t @@ e :->> w @@ e

ain’t the same as

(t :->> w) @@ e = (t @@ e) :->> (w @@ e)

which is what I meant. Differently grouped, it loops rather tightly. Took me ages to find it. Now that I’ve nailed that little sod, I can confirm that 2+2 is indeed 4.

I’ll commit the changes tomorrow, when I’ve yanked out all the tracing.

This entry was posted on Thursday, February 17th, 2005 at 11:29 pm and is filed under Hacking. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

2 Responses to “2+2…”

  1. Conor Says:
    February 18th, 2005 at 10:27 am

    OK, I’ve done a commit. There are a couple of files in the tests directory:

    • Four.epig does some basic arithmetic, including 4!. Shocking…
    • NatVec.epig gets as far as vector concatenation. Edwin, check out the two subtly different definitions of vector elimination.
  2. Conor Says:
    February 18th, 2005 at 2:33 pm

    I’ve fixed the precedence levels so the original does what it’s supposed to.

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