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<pre><a name="line-1"></a><span class='hs-comment'>{-|
<a name="line-2"></a> /NOTE/: This module is preliminary and may change at a future date.
<a name="line-3"></a>
<a name="line-4"></a> This module is intended to help converting a list of tags into a
<a name="line-5"></a> tree of tags.
<a name="line-6"></a>-}</span>
<a name="line-7"></a>
<a name="line-8"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>HTML</span><span class='hs-varop'>.</span><span class='hs-conid'>TagSoup</span><span class='hs-varop'>.</span><span class='hs-conid'>Tree</span>
<a name="line-9"></a> <span class='hs-layout'>(</span>
<a name="line-10"></a> <span class='hs-conid'>TagTree</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>tagTree</span><span class='hs-layout'>,</span>
<a name="line-11"></a> <span class='hs-varid'>flattenTree</span><span class='hs-layout'>,</span> <span class='hs-varid'>transformTree</span><span class='hs-layout'>,</span> <span class='hs-varid'>universeTree</span>
<a name="line-12"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-13"></a>
<a name="line-14"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>HTML</span><span class='hs-varop'>.</span><span class='hs-conid'>TagSoup</span><span class='hs-varop'>.</span><span class='hs-conid'>Type</span>
<a name="line-15"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Arrow</span>
<a name="line-16"></a>
<a name="line-17"></a>
<a name="line-18"></a><a name="TagTree"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TagBranch</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Attribute</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span>
<a name="line-19"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TagLeaf</span> <span class='hs-layout'>(</span><span class='hs-conid'>Tag</span> <span class='hs-varid'>str</span><span class='hs-layout'>)</span>
<a name="line-20"></a> <span class='hs-keyword'>deriving</span> <span class='hs-layout'>(</span><span class='hs-conid'>Eq</span><span class='hs-layout'>,</span><span class='hs-conid'>Ord</span><span class='hs-layout'>,</span><span class='hs-conid'>Show</span><span class='hs-layout'>)</span>
<a name="line-21"></a>
<a name="line-22"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Functor</span> <span class='hs-conid'>TagTree</span> <span class='hs-keyword'>where</span>
<a name="line-23"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagBranch</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-varid'>z</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TagBranch</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span><span class='hs-varop'>***</span><span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-varid'>z</span><span class='hs-layout'>)</span>
<a name="line-24"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagLeaf</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TagLeaf</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-25"></a>
<a name="line-26"></a>
<a name="line-27"></a><a name="tagTree"></a><span class='hs-comment'>-- | Convert a list of tags into a tree. This version is not lazy at</span>
<a name="line-28"></a><span class='hs-comment'>-- all, that is saved for version 2.</span>
<a name="line-29"></a><span class='hs-definition'>tagTree</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Eq</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'>=></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Tag</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span>
<a name="line-30"></a><span class='hs-definition'>tagTree</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>g</span>
<a name="line-31"></a> <span class='hs-keyword'>where</span>
<a name="line-32"></a> <span class='hs-varid'>g</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Eq</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'>=></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Tag</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span>
<a name="line-33"></a> <span class='hs-varid'>g</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-34"></a> <span class='hs-varid'>g</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span> <span class='hs-varop'>++</span> <span class='hs-varid'>map</span> <span class='hs-conid'>TagLeaf</span> <span class='hs-layout'>(</span><span class='hs-varid'>take</span> <span class='hs-num'>1</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-varop'>++</span> <span class='hs-varid'>g</span> <span class='hs-layout'>(</span><span class='hs-varid'>drop</span> <span class='hs-num'>1</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-35"></a> <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span>
<a name="line-36"></a>
<a name="line-37"></a> <span class='hs-comment'>-- the second tuple is either null or starts with a close</span>
<a name="line-38"></a> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Eq</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'>=></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Tag</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Tag</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-39"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagOpen</span> <span class='hs-varid'>name</span> <span class='hs-varid'>atts</span><span class='hs-conop'>:</span><span class='hs-varid'>rest</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-40"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>f</span> <span class='hs-varid'>rest</span> <span class='hs-keyword'>of</span>
<a name="line-41"></a> <span class='hs-layout'>(</span><span class='hs-varid'>inner</span><span class='hs-layout'>,</span><span class='hs-conid'>[]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>TagLeaf</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagOpen</span> <span class='hs-varid'>name</span> <span class='hs-varid'>atts</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>inner</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-42"></a> <span class='hs-layout'>(</span><span class='hs-varid'>inner</span><span class='hs-layout'>,</span><span class='hs-conid'>TagClose</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-43"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>x</span> <span class='hs-varop'>==</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagBranch</span> <span class='hs-varid'>name</span> <span class='hs-varid'>atts</span> <span class='hs-varid'>inner</span><span class='hs-conop'>:</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-44"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>TagLeaf</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagOpen</span> <span class='hs-varid'>name</span> <span class='hs-varid'>atts</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>inner</span><span class='hs-layout'>,</span> <span class='hs-conid'>TagClose</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-45"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-str'>"TagSoup.Tree.tagTree: safe as - forall x . isTagClose (snd (f x))"</span>
<a name="line-46"></a>
<a name="line-47"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagClose</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-conid'>TagClose</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-48"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagLeaf</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-49"></a> <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span>
<a name="line-50"></a> <span class='hs-varid'>f</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-51"></a>
<a name="line-52"></a>
<a name="line-53"></a><a name="flattenTree"></a><span class='hs-definition'>flattenTree</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Tag</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span>
<a name="line-54"></a><span class='hs-definition'>flattenTree</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concatMap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span>
<a name="line-55"></a> <span class='hs-keyword'>where</span>
<a name="line-56"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagBranch</span> <span class='hs-varid'>name</span> <span class='hs-varid'>atts</span> <span class='hs-varid'>inner</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-57"></a> <span class='hs-conid'>TagOpen</span> <span class='hs-varid'>name</span> <span class='hs-varid'>atts</span> <span class='hs-conop'>:</span> <span class='hs-varid'>flattenTree</span> <span class='hs-varid'>inner</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagClose</span> <span class='hs-varid'>name</span><span class='hs-keyglyph'>]</span>
<a name="line-58"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagLeaf</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
<a name="line-59"></a>
<a name="line-60"></a>
<a name="line-61"></a><a name="universeTree"></a><span class='hs-comment'>-- | This operation is based on the Uniplate @universe@ function. Given a</span>
<a name="line-62"></a><span class='hs-comment'>-- list of trees, it returns those trees, and all the children trees at</span>
<a name="line-63"></a><span class='hs-comment'>-- any level. For example:</span>
<a name="line-64"></a><span class='hs-comment'>--</span>
<a name="line-65"></a><span class='hs-comment'>-- > universeTree</span>
<a name="line-66"></a><span class='hs-comment'>-- > [TagBranch "a" [("href","url")] [TagBranch "b" [] [TagLeaf (TagText "text")]]]</span>
<a name="line-67"></a><span class='hs-comment'>-- > == [TagBranch "a" [("href","url")] [TagBranch "b" [] [TagLeaf (TagText "text")]]]</span>
<a name="line-68"></a><span class='hs-comment'>-- > ,TagBranch "b" [] [TagLeaf (TagText "text")]]</span>
<a name="line-69"></a><span class='hs-comment'>--</span>
<a name="line-70"></a><span class='hs-comment'>-- This operation is particularly useful for queries. To collect all @\"a\"@</span>
<a name="line-71"></a><span class='hs-comment'>-- tags in a tree, simply do:</span>
<a name="line-72"></a><span class='hs-comment'>--</span>
<a name="line-73"></a><span class='hs-comment'>-- > [x | x@(TagTree "a" _ _) <- universeTree tree]</span>
<a name="line-74"></a><span class='hs-definition'>universeTree</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span>
<a name="line-75"></a><span class='hs-definition'>universeTree</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concatMap</span> <span class='hs-varid'>f</span>
<a name="line-76"></a> <span class='hs-keyword'>where</span>
<a name="line-77"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>TagBranch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>inner</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t</span> <span class='hs-conop'>:</span> <span class='hs-varid'>universeTree</span> <span class='hs-varid'>inner</span>
<a name="line-78"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
<a name="line-79"></a>
<a name="line-80"></a>
<a name="line-81"></a><a name="transformTree"></a><span class='hs-comment'>-- | This operation is based on the Uniplate @transform@ function. Given a</span>
<a name="line-82"></a><span class='hs-comment'>-- list of trees, it applies the function to every tree in a bottom-up</span>
<a name="line-83"></a><span class='hs-comment'>-- manner. This operation is useful for manipulating a tree - for example</span>
<a name="line-84"></a><span class='hs-comment'>-- to make all tag names upper case:</span>
<a name="line-85"></a><span class='hs-comment'>--</span>
<a name="line-86"></a><span class='hs-comment'>-- > upperCase = transformTree f</span>
<a name="line-87"></a><span class='hs-comment'>-- > where f (TagBranch name atts inner) = [TagBranch (map toUpper name) atts inner]</span>
<a name="line-88"></a><span class='hs-comment'>-- > f x = x</span>
<a name="line-89"></a><span class='hs-definition'>transformTree</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TagTree</span> <span class='hs-varid'>str</span><span class='hs-keyglyph'>]</span>
<a name="line-90"></a><span class='hs-definition'>transformTree</span> <span class='hs-varid'>act</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concatMap</span> <span class='hs-varid'>f</span>
<a name="line-91"></a> <span class='hs-keyword'>where</span>
<a name="line-92"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>TagBranch</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>inner</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>act</span> <span class='hs-varop'>$</span> <span class='hs-conid'>TagBranch</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-layout'>(</span><span class='hs-varid'>transformTree</span> <span class='hs-varid'>act</span> <span class='hs-varid'>inner</span><span class='hs-layout'>)</span>
<a name="line-93"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>act</span> <span class='hs-varid'>x</span>
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