summaryrefslogtreecommitdiff
path: root/dev-haskell/lens-simple/metadata.xml
diff options
context:
space:
mode:
authorV3n3RiX <venerix@redcorelinux.org>2017-10-09 18:53:29 +0100
committerV3n3RiX <venerix@redcorelinux.org>2017-10-09 18:53:29 +0100
commit4f2d7949f03e1c198bc888f2d05f421d35c57e21 (patch)
treeba5f07bf3f9d22d82e54a462313f5d244036c768 /dev-haskell/lens-simple/metadata.xml
reinit the tree, so we can have metadata
Diffstat (limited to 'dev-haskell/lens-simple/metadata.xml')
-rw-r--r--dev-haskell/lens-simple/metadata.xml76
1 files changed, 76 insertions, 0 deletions
diff --git a/dev-haskell/lens-simple/metadata.xml b/dev-haskell/lens-simple/metadata.xml
new file mode 100644
index 000000000000..743355961e37
--- /dev/null
+++ b/dev-haskell/lens-simple/metadata.xml
@@ -0,0 +1,76 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+ <maintainer type="project">
+ <email>haskell@gentoo.org</email>
+ <name>Gentoo Haskell</name>
+ </maintainer>
+ <longdescription>
+ This module, &lt;http://hackage.haskell.org/package/lens-simple/docs/Lens-Simple.html Lens.Simple&gt;,
+ just re-exports the main modules from Russell O\'Connor's
+ &lt;http://hackage.haskell.org/package/lens-family lens-family&gt; package, the
+ original van Laarhoven-O'Connor lens library.
+ @lens-family@ is particularly remarkable for its minute number of dependencies:
+ (apart from &lt;http://hackage.haskell.org/package/mtl mtl&gt;
+ they are all ghc \'boot\' libraries); but more importantly for its
+ extreme conceptual simplicity and theoretical soundness. Much of
+ the material it contains is well-explained, from a tutorial point of view, by
+ &lt;http://hackage.haskell.org/package/lens-tutorial lens-tutorial&gt; It is independent,
+ self-standing and readily intelligible apart from any darker
+ more general system of combinators that might attempt to extend it. Much
+ of it ought to be in the Prelude.
+
+ Convenient import of the elementary combinators from @lens-family@,
+ however, a little complicated. The idea of this trivial module, then, is just to make a sort of
+ low-powered, minimal-dependency, @lens-family@ equivalent of
+ the 800 lb gorilla of lens library imports:
+
+ &gt; import Control.Lens
+
+ namely, the light-weight and elegant:
+
+ &gt; import Lens.Simple
+
+ Check it out, it's even one character shorter!
+
+ The material in &lt;http://hackage.haskell.org/package/lens-tutorial lens-tutorial&gt;
+ will work fine if you make this substitution in the underlying
+ &lt;http://hackage.haskell.org/package/lens-tutorial-1.0.0/docs/src/Control-Lens-Tutorial.html source&gt;
+ and follow along as prompted.
+
+ As another illustration of the simplicity of the
+ fundamental van Laarhoven-O'Connor lens combinators - and their homogeneity with
+ @Control.Lens@ - note that the gloss
+ &lt;https://github.com/michaelt/lens-family-simple/blob/master/examples/Pong.hs pong example&gt;
+ from the @lens@ library examples directory - which continues to be
+ among the best introductory lens tutorials precisely by saying nothing -
+ requires only this abbreviating change of imports.
+
+ If you make that program more complicated,
+ you might of course end up needing
+ the more sophisticated material in @Control.Lens@ and
+ its immense mass of dependencies. On the other hand,
+ you might just need some of the additional material
+ present in the similarly demystifying
+ &lt;http://hackage.haskell.org/package/microlens microlens&gt;
+ or &lt;http://hackage.haskell.org/package/microlens-th microlens-th&gt; and
+ the associated modules.
+
+ This module was originally intended to simplify the use of packages that
+ follow the original promise of the van Laarhoven-O'Connor lenses.
+ /Correct practice is to export lenses without depending on a lens-library, where possible./
+ In basic cases these just use familiar @Prelude@ types, after all.
+ Examples of best practices in this respect are e.g. &lt;http://hackage.haskell.org/package/lens-family-th lens-family-th&gt; which
+ doesn't depend on @lens-family@ despite its name and pipes-related packages like
+ &lt;http://hackage.haskell.org/package/pipes-bytestring pipes-bytestring&gt;
+ and &lt;http://hackage.haskell.org/package/pipes-group pipes-group&gt;.
+
+ @Lens.Simple@ also re-exports @makeLenses@ and
+ other convenient TH incantations from Dan Burton's associated
+ &lt;http://hackage.haskell.org/package/lens-family-th lens-family-th&gt;.
+
+ </longdescription>
+ <upstream>
+ <remote-id type="github">michaelt/lens-simple</remote-id>
+ </upstream>
+</pkgmetadata>