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authorV3n3RiX <venerix@redcorelinux.org>2017-12-01 03:04:39 +0000
committerV3n3RiX <venerix@redcorelinux.org>2017-12-01 03:04:39 +0000
commit407525b571b48cfd65e1ad7a02d250a927c967c9 (patch)
tree844bea44d85dc7218f54970af1c42cc9d55c3f1a /dev-haskell/semigroupoids/metadata.xml
parent89c6c06b8c42107dd231687a1012354e7d3039fc (diff)
gentoo resync : 01.12.2017
Diffstat (limited to 'dev-haskell/semigroupoids/metadata.xml')
-rw-r--r--dev-haskell/semigroupoids/metadata.xml66
1 files changed, 38 insertions, 28 deletions
diff --git a/dev-haskell/semigroupoids/metadata.xml b/dev-haskell/semigroupoids/metadata.xml
index f7fae28fcf66..d6c06edca015 100644
--- a/dev-haskell/semigroupoids/metadata.xml
+++ b/dev-haskell/semigroupoids/metadata.xml
@@ -7,18 +7,18 @@
</maintainer>
<longdescription>
Provides a wide array of semigroupoids and operations for working with semigroupds.
-
+
A Semigroupoid is a Category without the requirement of identity arrows for every object in the category.
-
+
When working with comonads you often have the @\&lt;*\&gt;@ portion of an @Applicative@, but
not the @pure@. This was captured in Uustalu and Vene's \"Essence of Dataflow Programming\"
in the form of the @ComonadZip@ class in the days before @Applicative@. Apply provides a weaker invariant, but for the comonads used for data flow programming (found in the streams package), this invariant is preserved. Applicative function composition forms a semigroupoid.
-
+
Similarly many structures are nearly a comonad, but not quite, for instance lists provide a reasonable 'extend' operation in the form of 'tails', but do not always contain a value.
-
-
+
+
Ideally the following relationships would hold:
-
+
&gt; Traversable &lt;---- Foldable &lt;--- Functor ------&gt; Alt ---------&gt; Plus Semigroupoid
&gt; | | | | |
&gt; v v v v v
@@ -27,36 +27,46 @@
&gt; v v v v
&gt; Bind ---------&gt; Monad -------&gt; MonadPlus Arrow
&gt;
-
+
Apply, Bind, and Extract give rise the Static, Kleisli and Cokleisli semigroupoids respectively.
-
+
This lets us remove many of the restrictions from various monad transformers
as in many cases the binding operation or @\&lt;*\&gt;@ operation does not require them.
-
+
Finally, to work with these weaker structures it is beneficial to have containers
that can provide stronger guarantees about their contents, so versions of 'Traversable'
and 'Foldable' that can be folded with just a 'Semigroup' are added.
</longdescription>
<use>
- <flag name="comonad">You can disable the use of the `comonad` package using
- `-f-comonad`. Disabling this is an unsupported configuration, but it may be
- useful for accelerating builds in sandboxes for expert users. If disabled we
- will not supply instances of `Comonad`</flag>
- <flag name="containers">You can disable the use of the `containers` package
- using `-f-containers`. Disabing this is an unsupported configuration, but it
- may be useful for accelerating builds in sandboxes for expert users.</flag>
- <flag name="contravariant">You can disable the use of the `contravariant`
- package using `-f-contravariant`. Disabling this is an unsupported
- configuration, but it may be useful for accelerating builds in sandboxes for
- expert users. If disabled we will not supply instances of `Contravariant`</flag>
- <flag name="distributive">You can disable the use of the `distributive`
- package using `-f-distributive`. Disabling this is an unsupported
- configuration, but it may be useful for accelerating builds in sandboxes for
- expert users. If disabled we will not supply instances of `Distributive`</flag>
- <flag name="tagged">You can disable the use of the `tagged` package
- using `-f-tagged`. Disabing this is an unsupported
- configuration, but it may be useful for accelerating builds in
- sandboxes for expert users.</flag>
+ <flag name="comonad">
+ You can disable the use of the `comonad` package using
+ `-f-comonad`. Disabling this is an unsupported configuration, but it may be
+ useful for accelerating builds in sandboxes for expert users. If disabled we
+ will not supply instances of `Comonad`
+ </flag>
+ <flag name="containers">
+ You can disable the use of the `containers` package
+ using `-f-containers`. Disabing this is an unsupported configuration, but it
+ may be useful for accelerating builds in sandboxes for expert users.
+ </flag>
+ <flag name="contravariant">
+ You can disable the use of the `contravariant`
+ package using `-f-contravariant`. Disabling this is an unsupported
+ configuration, but it may be useful for accelerating builds in sandboxes for
+ expert users. If disabled we will not supply instances of `Contravariant`
+ </flag>
+ <flag name="distributive">
+ You can disable the use of the `distributive`
+ package using `-f-distributive`. Disabling this is an unsupported
+ configuration, but it may be useful for accelerating builds in sandboxes for
+ expert users. If disabled we will not supply instances of `Distributive`
+ </flag>
+ <flag name="tagged">
+ You can disable the use of the `tagged` package
+ using `-f-tagged`. Disabing this is an unsupported
+ configuration, but it may be useful for accelerating builds in
+ sandboxes for expert users.
+ </flag>
</use>
<upstream>
<remote-id type="github">ekmett/semigroupoids</remote-id>