Question

Although I know that I can use &quote, I was wondering if there was a less blunt and long way, such as \", or the like.
Here is an example of the XML:

<root name="test" type="Node" action="{puts :ROOT.to_s}">
    <leaf type="Node" decider="{print :VAL1.to_s; gets.chomp.to_i}" action="{puts :ONE.to_s}" />
    <leaf type="Node" decider="{print :VAL2.to_s; gets.chomp.to_i}" action="{puts :TWO.to_s}" />
    <branch type="Node" decider="{100}" action="{}">
        <leaf type="LikelihoodNode" decider="{100}" action="{puts :HI.to_s}" arg="0"/>
    </branch>
</root>

The attributes that need this are decider and action. Right now the embedded code is using a little :sym.to_s hack, but that is not a solution.

NOTE: Although the action attribute is only a block in brackets, the processing code pre-pends the lambda.

Answer 1

A double quote inside an XML attribute is written as &quote; (or " or "). You’ll have similar issues with single quotes too so you can’t use those. However, you can use % as-is in an XML attribute so %|...|, %Q|...|, and %q|...| are available and they’re as easy to read and type as quotes:

<root name="test" type="Node" action="{puts %|ROOT|}">
    <leaf type="Node" decider="{print %|VAL1|; gets.chomp.to_i}" action="{puts %|ONE|}" />
    <!-- ... -->
</root>

Choose whichever delimiters you find the easiest to type and read.

You can also use single quotes for your attributes in XML so you can have:

<leaf type='Node' decider='{print "VAL1"; gets.chomp.to_i}' ...

But then you’d have to use ' inside the attribute if you needed to include a single quote.

Alternatively, you could switch to elements instead of attributes:

<leaf type="Node">
    <decider><![CDATA[
        print "VAL1"
        gets.chomp.to_i
    ]]></decider>
    <action><![CDATA[
        puts "ONE"
    ]]></decider>
</leaf>

but that’s a bit verbose, ugly, and not as easy to work with as attributes (IMHO).