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authorAnthony Ramine <[email protected]>2012-11-12 10:07:37 +0100
committerAnthony Ramine <[email protected]>2013-12-12 12:54:24 +0100
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Document named fun expressions
Diffstat (limited to 'system')
-rw-r--r--system/doc/reference_manual/expressions.xml23
1 files changed, 14 insertions, 9 deletions
diff --git a/system/doc/reference_manual/expressions.xml b/system/doc/reference_manual/expressions.xml
index 0dc6bfe576..e9de3e006e 100644
--- a/system/doc/reference_manual/expressions.xml
+++ b/system/doc/reference_manual/expressions.xml
@@ -954,19 +954,20 @@ Ei = Value |
<title>Fun Expressions</title>
<pre>
fun
- (Pattern11,...,Pattern1N) [when GuardSeq1] ->
- Body1;
+ [Name](Pattern11,...,Pattern1N) [when GuardSeq1] ->
+ Body1;
...;
- (PatternK1,...,PatternKN) [when GuardSeqK] ->
- BodyK
+ [Name](PatternK1,...,PatternKN) [when GuardSeqK] ->
+ BodyK
end</pre>
<p>A fun expression begins with the keyword <c>fun</c> and ends
with the keyword <c>end</c>. Between them should be a function
declaration, similar to a
- <seealso marker="functions#syntax">regular function declaration</seealso>, except that no function name is
- specified.</p>
- <p>Variables in a fun head shadow variables in the
- function clause surrounding the fun expression, and
+ <seealso marker="functions#syntax">regular function declaration</seealso>,
+ except that the function name is optional and should be a variable if
+ any.</p>
+ <p>Variables in a fun head shadow the function name and both shadow
+ variables in the function clause surrounding the fun expression, and
variables bound in a fun body are local to the fun body.</p>
<p>The return value of the expression is the resulting fun.</p>
<p>Examples:</p>
@@ -978,7 +979,11 @@ end</pre>
3> <input>Fun2 = fun (X) when X>=5 -> gt; (X) -> lt end.</input>
#Fun&lt;erl_eval.6.39074546&gt;
4> <input>Fun2(7).</input>
-gt</pre>
+gt
+5> <input>Fun3 = fun Fact(1) -> 1; Fact(X) when X > 1 -> X * Fact(X - 1) end.</input>
+#Fun&lt;erl_eval.6.39074546&gt;
+6> <input>Fun3(4).</input>
+24</pre>
<p>The following fun expressions are also allowed:</p>
<pre>
fun Name/Arity