Why do you want to get the result either in an array or in a scalar? Why not always get an array and always process it the same way? Why special case 1-element arrays?

Whichever you choose, XML::Simple can do it. If you want to always get an array use the ForceArray option, otherwise don't.

If you are only interested in the data in the State elements, then you can use a number of other modules, XML::LibXML, XML::Rules, or my XML::Twig.

++ for always treating it as an array.

#!/usr/local/bin/perl

use strict;
use warnings;

use XML::LibXML;

my $xml = <<_XML;
<GEN_FSM>
  <State>
    <Name>POWERED</Name>
    <Comment>USB POWERED State</Comment>
  </State>
  <State>
    <Name>DEFAULT</Name>
    <Comment>USB DEFAULT State</Comment>
  </State>
  <State>
    <Name>ADDRESS</Name>
    <Comment>USB ADDRESS State</Comment>
  </State>
  <Rst_Arc>
    <To_State>DEFAULT</To_State>
    <monitor_mode_event_name>HOT_RST</monitor_mode_event_name>
    <monitor_mode_event_count>1</monitor_mode_event_count>
    <comment>HOT_reset_to_DEFAULT</comment>
  </Rst_Arc>
</GEN_FSM>
_XML

my $parser = XML::LibXML->new();
my $doc    = $parser->parse_string( $xml );
my $root   = $doc->getDocumentElement;
my @nodes  = $root->findnodes( '/GEN_FSM/State/Name' );
foreach my $node ( @nodes ) {
  print $node->textContent, "\n";
}
[download]

-derby

That is not XML.

In case 'B' it returns me an array of hashes of B's data.

What is it? Please write a complete, self-contained program that demonstrates what you get, and how it differes from what you want ( see How (Not) To Ask A Question ).

That is not XML.

I'm not quite sure how to interpret the multiple entries under same tag name can exist.. On the other hand tags can repeat an even values within tags can repeat (though there are better solutions). In both cases it is well formed XML.

With minor edits the example provided is well formed XML.

<?xml version="1.0" encoding="UTF-8"?>

<GEN_FSM xsi:noNamespaceSchemaLocation="Desktop/test.xsd" xmlns:xsi="h
+ttp://www.w3.org/2001/XMLSchema-instance">
<State>
<Name>POWERED</Name>
<Comment>USB POWERED State</Comment>
</State>
<State>
<Name>DEFAULT</Name>
<Comment>USB DEFAULT State</Comment>
</State>
<State>
<Name>ADDRESS</Name>
<Comment>USB ADDRESS State</Comment>
</State>
<Rst_Arc>
<To_State>DEFAULT</To_State>
<monitor_mode_event_name>HOT_RST</monitor_mode_event_name>
<monitor_mode_event_count>1</monitor_mode_event_count>
<comment>HOT_reset_to_DEFAULT</comment>
</Rst_Arc>
</GEN_FSM>
[download]

It can even be validated by a schema (auto generated):

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema elementFormDefault="qualified" xmlns:xsd="http://www.w3.or
+g/2001/XMLSchema">
    <xsd:element name="GEN_FSM">
        <xsd:complexType>
            <xsd:choice minOccurs="0" maxOccurs="unbounded">
                <xsd:element ref="State"/>
                <xsd:element ref="Rst_Arc"/>
            </xsd:choice>
        </xsd:complexType>
    </xsd:element>
    <xsd:element name="State">
        <xsd:complexType mixed="true">
            <xsd:choice minOccurs="0" maxOccurs="unbounded">
                <xsd:element ref="Name"/>
                <xsd:element ref="Comment"/>
            </xsd:choice>
        </xsd:complexType>
    </xsd:element>
    <xsd:element name="Name" type="xsd:string"/>
    <xsd:element name="Comment" type="xsd:string"/>
    <xsd:element name="Rst_Arc">
        <xsd:complexType mixed="true">
            <xsd:choice minOccurs="0" maxOccurs="unbounded">
                <xsd:element ref="To_State"/>
                <xsd:element ref="monitor_mode_event_name"/>
                <xsd:element ref="monitor_mode_event_count"/>
                <xsd:element ref="comment"/>
            </xsd:choice>
        </xsd:complexType>
    </xsd:element>
    <xsd:element name="To_State" type="xsd:string"/>
    <xsd:element name="monitor_mode_event_name" type="xsd:string"/>
    <xsd:element name="monitor_mode_event_count" type="xsd:integer"/>
    <xsd:element name="comment" type="xsd:string"/>
</xsd:schema>
[download]

Cheers

Harry