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| author | David Feuer <david.feuer@gmail.com> | 2014-12-09 18:12:33 -0600 |
|---|---|---|
| committer | Austin Seipp <austin@well-typed.com> | 2014-12-09 19:59:27 -0600 |
| commit | 8b480d3192e6eff6183934d7bbcc2054611c3651 (patch) | |
| tree | a4748104121093f932254b3234efd6cbbfaa3a5d /docs/users_guide/bugs.xml | |
| parent | 09b7943321f89b945d10f8a914f4c2cbf73dff91 (diff) | |
| download | haskell-8b480d3192e6eff6183934d7bbcc2054611c3651.tar.gz | |
Document splitAt deviation from the Report
Summary:
`splitAt` is stricter than the Report specifies, so we should
say so.
Reviewers: hvr, austin
Reviewed By: austin
Subscribers: carter, thomie
Projects: #ghc
Differential Revision: https://phabricator.haskell.org/D562
GHC Trac Issues: #9870
Diffstat (limited to 'docs/users_guide/bugs.xml')
| -rw-r--r-- | docs/users_guide/bugs.xml | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/docs/users_guide/bugs.xml b/docs/users_guide/bugs.xml index 2d6fc6583b..30770f0f90 100644 --- a/docs/users_guide/bugs.xml +++ b/docs/users_guide/bugs.xml @@ -292,6 +292,17 @@ checking for duplicates. The reason for this is efficiency, pure and simple. </listitem> </varlistentry> <varlistentry> + <term><literal>splitAt</literal> semantics</term> + <para><literal>Data.List.splitAt</literal> is stricter than specified in the + Report. Specifically, the Report specifies that +<programlisting>splitAt n xs = (take n xs, drop n xs)</programlisting> + which implies that +<programlisting>splitAt undefined undefined = (undefined, undefined)</programlisting> + but GHC's implementation is strict in its first argument, so +<programlisting>splitAt undefined [] = undefined</programlisting> + </para> + </varlistentry> + <varlistentry> <term><literal>zip</literal> and <literal>zipWith</literal> semantics</term> <para><literal>zip</literal> and <literal>zipWith</literal> can give less defined results than the Report specifies in certain cases. This deviation |