Hello gentle Haskell folks,
I happened to read Beautiful code's chapter 1 today and found Brian
Kerninghan's regex implementation. In it he only shows the * meta character.
I can easily understand how + can be built but am having trouble with
building ? (zero or one). I'd really appreciate it if
I guess you mean the function that converts an abstract syntax tree to
a directed acyclic graph (DAG).
Just for completeness I should mention that if the object language has
effects including non-termination, one has to be careful eliminating
seemingly common expressions. For example, in
Hi,
Perhaps I did not understand the question properly, but it looks very
straight forward :
oneOrNone x = fmap Just x | pure Nothing
it will have a type of oneOrNone :: (Alternative f) = f a - f (Maybe a)
In fact, there is a function called optional in Control.Applicative[1]
which does
I can easily understand how + can be built but am having trouble with
building ? (zero or one).
If there is a regular expression e for the empty word, one can define ? as
a? = e | a
If there is a regular expression o that never matches one can define e as
e = o*
If there are
On Fri, Aug 12, 2011 at 4:34 PM, Sebastian Fischer fisc...@nii.ac.jpwrote:
I can easily understand how + can be built but am having trouble with
building ? (zero or one).
If there is a regular expression e for the empty word, one can define ? as
a? = e | a
If there is a regular
1) Some of the GHC programs contributed to the benchmarks game have problems
with recent GHC releases
- meteor-contest #5 - Ambiguous occurrence `permutations'
http://shootout.alioth.debian.org/u64q/program.php?test=meteorlang=ghcid=5#log
- regex-dna #2 - Precedence parsing error
Hello Isaac,
On Fri, Aug 12, 2011 at 10:18 AM, Isaac Gouy igo...@yahoo.com wrote:
1) Some of the GHC programs contributed to the benchmarks game have problems
with recent GHC releases
- meteor-contest #5 - Ambiguous occurrence `permutations'
Just to make it explicit, is it
\a i -
let t = a ! i in
if i = 0 then
t
else if i 0 then
t + a ! (i-1)
else
bad idea, because of last else-case? Can it be mended with
one another pass for if-expressions?
The upcoming
I think I have found a problem with the union function:
If you look here: http://hpaste.org/49889
You will see that line 4 gives a different result to lines 6, 8, 10;
this shouldn't be the case because union is commutative.
AC-Vector-Fancy is merely a fancy facard over AC-Vector. So the bug is
Note that data-reify will only find *some* common/equal sub-expressions,
namely the pointer-equal ones. In all of my code-generating (deep) DSLs,
it's been very important for efficiency to also pull out
equal-but-pointer-unequal expressions.
- Conal
On Thu, Aug 11, 2011 at 4:41 AM, Vo Minh
Hi,
Am Donnerstag, den 11.08.2011, 15:46 +0200 schrieb Peter Simons:
the home page of a package on Hackage links to various distributions to
show which versions are available, i.e. Fedora, Debian, FreeBSD, etc. In
NixOS, we have fairly up-to-date package set, and I would like to see
that
Do you mean that x and y in
x = a + 1
y = a + 1
are different from data-reify point of view?
2011/8/12 Conal Elliott co...@conal.net
Note that data-reify will only find *some* common/equal sub-expressions,
namely the pointer-equal ones. In all of my code-generating (deep) DSLs,
it's been
On Fri, 2011-08-12 at 11:44 -0500, austin seipp wrote:
2) I noticed `-fvia-C` has now gone away [...]
I can't forsee the potential performance ramifications, but frankly
-fvia-C has been deprecated/not-advised-for-use for quite a while now,
and I wonder how many of these programs just have
On 12.08.2011 18:44, austin seipp wrote:
Hello Isaac,
On Fri, Aug 12, 2011 at 10:18 AM, Isaac Gouyigo...@yahoo.com wrote:
1) Some of the GHC programs contributed to the benchmarks game have problems
with recent GHC releases
- meteor-contest #5 - Ambiguous occurrence `permutations'
--- On Fri, 8/12/11, austin seipp a...@hacks.yi.org wrote:
Thanks, I do like easy fixes :-)
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yes.
On Fri, Aug 12, 2011 at 11:02 AM, Anton Kholomiov anton.kholom...@gmail.com
wrote:
Do you mean that x and y in
x = a + 1
y = a + 1
are different from data-reify point of view?
2011/8/12 Conal Elliott co...@conal.net
Note that data-reify will only find *some* common/equal
Hi,
Why does the Haskell :type command only sometimes print the type-class?
Should I expect type-class inference as well as type inference?
Maybe the type-class is inferred where possible, but not always printed?
Thanks,
Pat
-- Code
k x = x + 3
data T = T
class A a where
g::a - a
g a = a
On Fri, 2011-08-12 at 23:52 +0100, Patrick Browne wrote:
-- Second in the case of a method of a type class.
-- Inferred Num
*Main :t g 3
g 3 :: forall t. (A t, Num t) = t
-- Did not print class A.
*Main :t g T
g T :: T
-- Did not print any class.
This is because you already know that T
On Fri, Aug 12, 2011 at 18:52, Patrick Browne patrick.bro...@dit.ie wrote:
Why does the Haskell :type command only sometimes print the type-class?
Haskell infers the most specific type applicable. If the most specific it
can get is a typeclass, that's what it produces; if it can infer an
On Fri, Aug 12, 2011 at 19:08, Brandon Allbery allber...@gmail.com wrote:
On Fri, Aug 12, 2011 at 18:52, Patrick Browne patrick.bro...@dit.iewrote:
Why does the Haskell :type command only sometimes print the type-class?
Haskell infers the most specific type applicable. If the most specific
On 8/12/11 12:52 PM, Anton Kholomiov wrote:
Just to make it explicit, is it
\a i -
let t = a ! i in
if i= 0 then
t
else if i 0 then
t + a ! (i-1)
else
bad idea, because of last else-case? Can it be mended with
one
On 8/12/2011 10:30 AM, Conal Elliott wrote:
Note that data-reify will only find *some* common/equal sub-expressions,
namely the pointer-equal ones. In all of my code-generating (deep)
DSLs, it's been very important for efficiency to also pull out
equal-but-pointer-unequal expressions.
-
in let t= a!i a!i might be out of bounds ?
On Fri, Aug 12, 2011 at 9:52 AM, Anton Kholomiov
anton.kholom...@gmail.comwrote:
Just to make it explicit, is it
\a i -
let t = a ! i in
if i = 0 then
t
else if i 0 then
t + a ! (i-1)
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