From ecd20cf55ffcc45632825863ea8f0c7442553a0d Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Tue, 23 Feb 2016 17:08:42 +0100
Subject: erts: Add tracing examples in match spec docs

---
 erts/doc/src/match_spec.xml | 41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

(limited to 'erts/doc')

diff --git a/erts/doc/src/match_spec.xml b/erts/doc/src/match_spec.xml
index b49e1483aa..3944f24f84 100644
--- a/erts/doc/src/match_spec.xml
+++ b/erts/doc/src/match_spec.xml
@@ -528,7 +528,7 @@
   </section>
 
   <section>
-    <title>Examples</title>
+    <title>ETS Examples</title>
     <p>Match an argument list of three where the first and third arguments 
       are equal:</p>
     <code type="none"><![CDATA[
@@ -619,5 +619,44 @@
     <p>The function <c><![CDATA[ets:test_ms/2]]></c> can be useful for testing
       complicated ets matches.</p>
   </section>
+  <section>
+    <title>Tracing Examples</title>
+    <p>Only generate trace message if trace control word is set to 1:</p>
+    <code type="none"><![CDATA[
+[{'_',
+  [{'==',{get_tcw},{const, 1}}],
+  []}]
+    ]]></code>
+    <p>Only generate trace message if there is a seq trace token:</p>
+    <code type="none"><![CDATA[
+[{'_',
+  [{'==',{is_seq_trace},{const, 1}}],
+  []}]
+    ]]></code>
+    <p>Remove 'silent' trace flag when first argument is 'verbose'
+    and add it when it is 'silent':</p>
+    <code type="none"><![CDATA[
+[{'$1',
+  [{'==',{hd, '$1'},verbose}],
+  [{trace, [silent],[]}]},
+ {'$1',
+  [{'==',{hd, '$1'},silent}],
+  [{trace, [],[silent]}]}]
+    ]]></code>
+    <p>Add return_trace message if function is of arity 3:</p>
+    <code type="none"><![CDATA[
+[{'$1',
+  [{'==',{length, '$1'},3}],
+  [{return_trace}]},
+ {'_',[],[]}]
+    ]]></code>
+    <p>Only generate trace message if function is of arity 3 and first argument is 'trace':</p>
+    <code type="none"><![CDATA[
+[{['trace','$2','$3'],
+  [],
+  []},
+ {'_',[],[]}]
+    ]]></code>
+  </section>
 </chapter>
 
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