There's no description of the multi-parameter type classes extension in the
3.01 user manual; are the extensions implemented as described in the link
below? (I vaguely recollect Simon posting a message on this subject more
recently, but I couldn't find it.)
While hacking around with MPCs, trying to define a variant of the
Collection class, mutated to suit my own fiendish ends, I ran into
this:
Intervals.hs:345:
Class type variable `e' does not appear in method signature
union2 :: s - s - s
What's the significance of this
year ago I had the pleasure of using a compiler (for BETA I think)
where the basic usage for a novice was Just What You Wanted:
% compiler Main.source
From there it figured out which other modules it needed, which
required recompiling, which object files and libraries where needed
Hi! Before raising my questions please point me in the appropriate direction
if these questions have been asked before. I have also just requested to join
the various Haskell mail lists. My questions are really concerned with the
commercial viability of Haskell especially in the face
| Jin Yang [EMAIL PROTECTED] writes ...
|
| I wrote a translator in Haskell and it was compiled OK using an earlier ghc
| version. Now the ghc at my department (Dept of Computing , Imperial) was
| upgrated to ghc0.26 and all my code got a compiling error:
|ld: Undefined symbol
|
At a guess I'd say that libpvm3.a is referring to "xdr_long",
"listen" etc, and no library has them. You'll need to find
a library that defines them and add a -l flag for it. I think.
Simon
| But then I tried :
| ghc -v -o a.out -L /usr/local/pvm3/lib/SUN4SOL2/ -lpvm3 Main.o
|
| and it
| What I'd really like is a command "specialize module Foo for type Bar",
| and moreover, this specialization should happen completely outside
| the text of module Foo. (Compare to an instanciation of a generic
| package in Ada.)
|
| Are there any magic ghc options/perl scripts (ouch) that
| grepping for "interface PreludeStdIO" in the 0.29 library interface files
| comes up with nothing, so maybe it's not really surprising. (Or is it yet
| more "magic"?..) Adding -fhaskell-1.3 does not help, either - the same error
| message appears, before it spots all the continuation I/O!
I
| However, in return, perhaps somebody can supply me with parse trees for
| the following:
|
| - - 1(accepted by nhc and hbc)
| (- 1 `n6` 1) where infix 6 `n6` (accepted by nhc, hbc, ghc)
| (- 1 `r6` 1) where infixr 6 `r6` (accepted by nhc,
| Sorry. GHC version 0.29. FiniteMap version 6, it seems ({-# GHC PRAGMA
| INTERFACE VERSION 6 #-} at the top). Compilation with verbose output appended
| to this message. It's messy ;)
In Convert.lhs, add
import PreludeStdIO( Maybe )
Simon
| I have a data structure Library, and two tools. One tool saves a Library,
| another one loads it. At the moment, Library must be "shown" by the first
| tool (i.e. converted to text format). This must then be re-parsed by the
| second tool.
|
| It would be much simpler, quicker etc. just to
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