Hi
1. I compile HelloWorld.hs by "yhc HelloWorld" and it works fine. However, in
contrast to the description on http://haskell.org/haskellwiki/Yhc/Tutorial,
the result is deposited in Main.hbc and Main.hi, so to run it, I must use
"yhi Main". "yhi HelloWorld" produces a complaint (ERROR: couldn't find
module named 'HelloWorld').
GHC has the same behaviour, at least on Windows, producing main.exe
always. I think if you pass the -hide option you'll get the correct
name for the HelloWorld.hbc but it might be in the wrong place. We are
currently not sure what to do about module name vs filename conflicts.
I guess the short term fix is to update the docs, the long term fix is
to make it produce a more logically named file.
2. When invoking yhc and also yhi, it seems that I can add a lot of different
suffixes to the module name and they are simply ignored. Thus, "yhi Main.xxx"
works just as well as "yhi Main". Throwing my input silently away like this
seems unfriendly, I would much prefer to get an error message.
It used to be that yhc always required the .hs extension and that yhi
never accepted an extension - that was really unfriendly :) That is a
bug, Main should be interpreted as Main.hbc or Main, but no further
than that.
3. On http://haskell.org/haskellwiki/Yhc/Options and also in the output from
"yhc -?", I find "-d -dst str destination path for generated bytecode
files (default=.)". This dosen't seem right: I the cases I have tried, the
bytecode was placed in the same directory as the source. And adding "-d
something" did not seem to have any effect.
Hmm, that seems weird. That sounds like a bug, I'll try and reproduce it later.
4. I also tried the command line yhe. However, I had to go into
yhc/src/interactive and figure out myself how to build it. It hadn't been
built as part of the "normal" build process. (I should mention that I am not
particularly interested in the GUI yhe and probably don't even have the
installments needed to build it.)
It's fallen out of focus, and was never great (it just shells out to
yhc then yhi). It may not build anymore, but if it does scons build
yhe would do it. The GUI was quite neat, but the requirements were an
unreleased Gtk2Hs version. Once a Gtk2Hs version gets released we'll
probably update it to work with that.
5. Getting to some more meaty things, actually compiling some code, I get the
message "Error: Context for Prelude.Num needed in left hand pattern at
98:19-98:23." referring to this line in the code:
(x,c) = prpExponent (n-1) p
In ghci, I find that
prpExponent :: (Num b, Integral a) => a -> a -> (a, b)
If I add
prpExponent :: Integer -> Integer -> (Integer,Int)
(I sinfully avoid these type specifications in many cases), the module
compiles fine. In another case of this:
(p2p1f2,0) = divMod (p2+1) p2p1f1
yhc reports "Error: Context for Prelude.Integral needed in left hand pattern
at 88:3-88:12.". For this, ghci reports
p2p1f2 :: Integer
p2 :: Integer
p2p1f1 :: Integer
and I can add
p2 :: Integer
to fix the problem. I have additional examples of this, all of them involving
a pair as left hand side, some of them requiring more elaborate (but less
obvious) repairs. Any comments?
Sounds like an nhc bug that carried over. I'll open a bug report for it.
6. I get the message "Nothing derived for Id 424 at nopos" and similar
messages with 424 replaced by other numbers when a number of modules are
compiled. The modules seem to compile OK, however. What does this mean?
Never seen that before. Can you attach a module that gives this behaviour?
7. I have only really managed to execute toy programs. For one of my "real"
programs (also a toy, but you know what I mean), I get
Thorkil-Naurs-Computer:~/tn/test/Yhc/HASKELL1/tn/Haskell/Hugs thorkilnaur$
yhi Primtal
ERROR: couldn't find module named '_Builtin'
tried:
_Builtin.hbc
/Users/thorkilnaur/tn/YhcDarcsRepository/yhc/inst/lib/yhc/packages/yhc-base/1.0/_Builtin.hbc
Thorkil-Naurs-Computer:~/tn/test/Yhc/HASKELL1/tn/Haskell/Hugs thorkilnaur$
and I cannot figure out how to solve this problem. Other of my programs also
complain that '_Builtin' is missing.
Weird, I think Tom might have more idea what's going on here.
8. Compiling another program, I get
Thorkil-Naurs-Computer:~/tn/test/Yhc/HASKELL1/tn/Haskell/Hugs thorkilnaur$
yhc -I EuclidNormal FcbMStep
yhc: Error: File not found, Time
Reason: imported from Main
Looked in:
/Users/thorkilnaur/tn/test/Yhc/HASKELL1/tn/Haskell/Hugs/
.
EuclidNormal
/Users/thorkilnaur/tn/YhcDarcsRepository/yhc/inst/lib/yhc/packages/haskell98/1.0
/Users/thorkilnaur/tn/YhcDarcsRepository/yhc/inst/lib/yhc/packages/yhc-base/1.0
Thorkil-Naurs-Computer:~/tn/test/Yhc/HASKELL1/tn/Haskell/Hugs thorkilnaur$
I have done a very superficial investigation and it appears that it is
certainly intended that Time should be included in the Yhc install. On the
other hand, I cannot off hand find traces in the scons output that something
related to Time has been built. I have similar problems with CPUTime. Please
direct me.
Maybe the build script is missing them. I've never tried to work with
Time or CPUTime. I'll try and figure out whats going on there.
9. Finally, I get a message "Error: Identifier getArgs used at 67:15-67:21 is
not defined." when using that function in a Main module:
args<-getArgs
Have you got import System.Environment? or import System? It's
possible that one of them is lacking a reexport of getArgs. I've
certainly used getArgs in a Yhc program before.
Please complain if you think that I am wasting your time with trivia.
On the contarary. This has been very helpful! If you look through the
bug list tomorrow you'll see all these issues on it :)
See you at Hac07
Neil
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