Edit text sections on associative arrays. Also tweak example two space indent.

1 files changed, 11 insertions, 11 deletions

diff --git a/doc/SystemTap_Beginners_Guide/en-US/Arrays.xml b/doc/SystemTap_Beginners_Guide/en-US/Arrays.xml
index 04e34de3..63c3df04 100644
--- a/doc/SystemTap_Beginners_Guide/en-US/Arrays.xml
+++ b/doc/SystemTap_Beginners_Guide/en-US/Arrays.xml
@@ -14,7 +14,7 @@
 <secondary>introduction</secondary>
 </indexterm>	
 
-<para>SystemTap also supports the use of associative arrays. While an ordinary variable represents a single value, associative arrays can represent a list of values. Simply put, an associative array is a collection of unique keys; each key in the array has a value associated with it.</para>
+<para>SystemTap also supports the use of associative arrays. While an ordinary variable represents a single value, associative arrays can represent a collection of values. Simply put, an associative array is a collection of unique keys; each key in the array has a value associated with it.</para>
 
 <!--<para>SystemTap also supports the use of associative arrays. While an ordinary variable represents a single value, associative arrays can represent a list of values. Simply put, an associative array is a collection of unique keys; each key in the array has a value associated with it. Illustrating this visually would be similar to creating a two-column table: the first column would have the unique key, while the second column would have each key's associated value. Each unique key and its associated value is referred to as a <emphasis>key pair</emphasis>.</para>-->
 
@@ -98,7 +98,7 @@
 <tertiary>arrays</tertiary>
 </indexterm>
 
-<para>Since associative arrays are normally processed in multiple probes (as we will demonstrate later), they are declared as <command>global</command> variables in the SystemTap script. The syntax for manipulating arrays (i.e. accessing elements in an associative array) is similar to that of <command>awk</command>, and is as follows:</para>
+<para>Since associative arrays are normally processed in multiple probes (as we will demonstrate later), they are declared as <command>global</command> variables in the SystemTap script. The syntax for accessing an element in an associative array is similar to that of <command>awk</command>, and is as follows:</para>
 <!-- next 3 indexterms for syntax -->
 <indexterm>
 <primary>arrays</primary>
@@ -126,10 +126,10 @@
 
 
 <screen>
-<replaceable>array_name</replaceable>[<replaceable>index_expression</replaceable>] <replaceable>operation</replaceable>
+<replaceable>array_name</replaceable>[<replaceable>index_expression</replaceable>]
 </screen>
 
-<para>Here, the <command><replaceable>array_name</replaceable></command> is any arbitrary name the array uses. The <command><replaceable>index_expression</replaceable></command> is used to refer to a specific unique key (or set of unique keys) in the array, and the <command><replaceable>operation</replaceable></command> defines what to do with the <command><replaceable>index_expression</replaceable></command>. To illustrate, let us try to build an array named <command>foo</command> that specifies the ages of three people (i.e. the unique keys): <command>tom</command>, <command>dick</command>, and <command>harry</command>. To assign them the ages (i.e. associated values) of 23, 24, and 25 respectively, we'd use the following array statements:</para> 
+<para>Here, the <command><replaceable>array_name</replaceable></command> is any arbitrary name the array uses. The <command><replaceable>index_expression</replaceable></command> is used to refer to a specific unique key in the array. To illustrate, let us try to build an array named <command>foo</command> that specifies the ages of three people (i.e. the unique keys): <command>tom</command>, <command>dick</command>, and <command>harry</command>. To assign them the ages (i.e. associated values) of 23, 24, and 25 respectively, we'd use the following array statements:</para> 
 
 <!-- next 2 indexterms for example -->
 
@@ -158,13 +158,13 @@ foo["dick"] = 24
 foo["harry"] = 25
 </screen>
 </example>
-<!--
-<para>You can specify up to 5 index expressons in an array statement, each one delimited by a comma (<command>,</command>). This is useful if you wish to perform the same operation to a set of key pairs. For example, to increase the associated value of all the key pairs defined by <xref linkend="arraysimplestexample"/>, you can use the following statement:</para>
+
+<para>You can specify up to 5 index expressons in an array statement, each one delimited by a comma (<command>,</command>). This is useful if you wish to have a key that contains multiple pieces of information. The following line from <xref linkend="scriptdisktop"/> uses 5 elements for the key: process ID, executable name, user ID, parent ID, and string "W". It associates the value of <command>devname</command> with that key.</para>
 
 <screen>
-foo["tom","dick","harry"] ++
+device[pid(),execname(),uid(),ppid(),"W"] = devname
 </screen>
--->
+
 <important>
 	<title>Important</title>
 	<para>All associate arrays must be declared as <command>global</command>, regardless of whether the associate array is used in one or multiple probes. </para>
@@ -220,13 +220,13 @@ probe begin {	foo[4,"hello"] ++ }
 
 <para>You can also use a handler function in as the <command><replaceable>unique_key</replaceable></command>. Doing so creates an associate array that uses the values returned by the handler function as the unique keys. The first time that a probe using this array returns a string value, that value is set as a unique key with an initial value of 0. The next time that the probe returns the same string value, it increments the associated value of the unique key by 1.</para>
 
-<para>For example, let's say you need to tally how many times each process performs a read to the virtual file system (VFS). To do this, probe the kernel function <command>vfs_read</command>, use the handler <command>execname()</command> to identify which processes performed the VFS read, and tally the reads of each process using the associative array named <command>reads</command>, as in</para>
+<para>For example, let's say you need to tally how many times each process performs a read to the virtual file system (VFS). To do this, probe the VFS read opeartion, use the handler <command>execname()</command> to identify which processes performed the VFS read, and tally the reads of each process using the associative array named <command>reads</command>, as in</para>
 
 <formalpara id="aaexamplesimplevfsreads">
 	<title>tallying-in-arrays.stp</title>
 <para>
 <programlisting>
-probe kernel.function("vfs_read")
+probe vfs.read
 { reads[execname()] += $count }
 </programlisting>
 </para>
@@ -234,4 +234,4 @@ probe kernel.function("vfs_read")
 
 <para>In <xref linkend="aaexamplesimplevfsreads"/>, the first time that the probe returns the process name <command>gnome-terminal</command> (i.e. the first time <command>gnome-terminal</command> performs a VFS read), that process name is set as a unique key. The next time that the probe returns the process name <command>gnome-terminal</command>, SystemTap increments the associated value of <command>gnome-terminal</command> by 1. SystemTap performs this operation for <emphasis>all</emphasis> process names as the probe returns them.</para>
 -->
-</section>
\ No newline at end of file
+</section>