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<h2><a name="examples"></a>Examples</h2>

<p>The code excerpt below creates a parser with 2 callbacks and

feeds a test string to it. The parsing of the test string triggers

the callbacks, printing the results.</p>

<pre class="example">

require"lxp"

local count = 0

callbacks = {

    StartElement = function (parser, name)

        io.write("+ ", string.rep(" ", count), name, "\n")

        count = count + 1

    end,

    EndElement = function (parser, name)

        count = count - 1

        io.write("- ", string.rep(" ", count), name, "\n")

    end

}

p = lxp.new(callbacks)

for l in io.lines() do  -- iterate lines

    p:parse(l)          -- parses the line

    p:parse("\n")       -- parses the end of line

end

p:parse()               -- finishes the document

p:close()               -- closes the parser

</pre>

<p>For a test string like</p>

<pre class="example">

<elem1>

    text

    <elem2/>

    more text

</elem1>

</pre>

<p>The example would print</p>

<pre class="example">

+ elem1

    + elem2

    - elem2

- elem1

</pre>

<p>Note that the text parts are not handled since the corresponding

callback (<em>CharacterData</em>) has not been defined. Also note

that defining this callback after the call to lxp.new would make no

difference. But had the callback table been defined as</p>

<pre class="example">

callbacks = {

    StartElement = function (parser, name)

        io.write("+ ", string.rep(" ", count), name, "\n")

        count = count + 1

    end,

    EndElement = function (parser, name)

        count = count - 1

        io.write("- ", string.rep(" ", count), name, "\n")

    end,

    CharacterData = function (parser, string)

        io.write("* ", string.rep(" ", count), string, "\n")

    end

}

</pre>

<p>The results would have been</p>

<pre class="example">

+ elem1

* text

    + elem2

    - elem2

* more text

- elem1

</pre>

<p>Another example would be the use of <em>false</em> as a

placeholder for the callback. Suppose that we would like to print

only the text associated with <em>elem2</em> elements and that the

XML sample is</p>

<pre class="example">

 <elem1>

    text

    <elem2>

        inside text

    </elem2>

    more text

</elem1>

</pre>

<p>We could define the new callback table as</p>

<pre class="example">

callbacks = {

    StartElement = function (parser, name)

      if name == "elem2" then

        -- redefines CharacterData behaviour

        callbacks.CharacterData = function (parser, string)

          io.write(string, "\n")

        end

      end

    end,

    EndElement = function (parser, name)

      if name == "elem2" then

        callbacks.CharacterData = false -- restores placeholder

      end

    end,

    CharacterData = false               -- placeholder

}

</pre>

<p>The results would have been</p>

<pre class="example">

inside text

</pre>

<p>Note that this example assumes no other elements are present

inside elem2 tags.</p>

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