dyaml/doc/html/api/dyaml.constructor.html

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<h1>dyaml.constructor</h1>
<!-- Generated by Ddoc from dyaml/constructor.d -->
<p>Implements a class that processes YAML mappings, sequences and scalars into
nodes. This can be used to implement custom data types. A tutorial can be
found <a href="../tutorials/custom_types.html">here</a>.</p>
<dl><dt class="d_decl">class <a name="ConstructorException"></a><span class="ddoc_psymbol">ConstructorException</span>: dyaml.exception.YAMLException;
</dt>
<dd><p>Exception thrown at constructor errors.
</p>
<p>Can be thrown by custom constructor functions.</p>
<dl><dt class="d_decl">this(string <b>msg</b>, Mark <b>start</b>, Mark <b>end</b>, string <b>file</b> = __FILE__, int <b>line</b> = __LINE__);
</dt>
<dd><p>Construct a ConstructorException.
</p>
<b>Parameters:</b><div class="pbr"><table class=parms><tr><td valign=top>string <b>msg</b></td>
<td valign=top>Error message.</td></tr>
<tr><td valign=top>Mark <b>start</b></td>
<td valign=top>Start position of the error context.</td></tr>
<tr><td valign=top>Mark <b>end</b></td>
<td valign=top>End position of the error context.</td></tr>
</table></div>
</dd>
</dl>
</dd>
<dt class="d_decl">class <a name="Constructor"></a><span class="ddoc_psymbol">Constructor</span>;
</dt>
<dd><p>Constructs YAML values.
</p>
<p>Each YAML scalar, sequence or mapping has a tag specifying its data type.
<a name="Constructor"></a><span class="ddoc_psymbol">Constructor</span> uses user-specifyable functions to create a node of desired
data type from a scalar, sequence or mapping.
<br>
Each of these functions is associated with a tag, and can process either
a scalar, a sequence, or a mapping. The constructor passes each value to
the function with corresponding tag, which then returns the resulting value
that can be stored in a node.
<br>
If a tag is detected with no known constructor function, it is considered an error.</p>
<dl><dt class="d_decl">this(in bool <b>defaultConstructors</b> = true);
</dt>
<dd><p>Construct a Constructor.
</p>
<p>If you don't want to support default YAML tags/data types, you can use
<b>defaultConstructors</b> to disable constructor functions for these.
</p>
<b>Parameters:</b><div class="pbr"><table class=parms><tr><td valign=top>bool <b>defaultConstructors</b></td>
<td valign=top>Use constructors for default YAML tags?</td></tr>
</table></div>
</dd>
<dt class="d_decl">void <a name="addConstructorScalar"></a><span class="ddoc_psymbol">addConstructorScalar</span>(T)(in string <b>tag</b>, T function(Mark, Mark, ref Node) <b>ctor</b>);
</dt>
<dd><p>Add a constructor function from scalar.
</p>
<p>The function must take two Marks (start and end positions of
the node in file) and a reference to Node to construct from.
The node contains a string for scalars, Node[] for sequences and
Node.Pair[] for mappings.
The value returned by this function will be stored in the resulting node.
<br>
Only one constructor function can be set for one tag.
</p>
<b>Parameters:</b><div class="pbr"><table class=parms><tr><td valign=top>tag</td>
<td valign=top>Tag for the function to handle.</td></tr>
<tr><td valign=top>ctor</td>
<td valign=top>Constructor function.</td></tr>
</table></div>
<p><b>Example:</b><br>
<pre class="d_code"> <span class="d_keyword">import</span> std.string;
<span class="d_keyword">import</span> yaml;
<span class="d_keyword">struct</span> MyStruct
{
<span class="d_keyword">int</span> x, y, z;
}
MyStruct constructMyStructScalar(Mark start, Mark end, <span class="d_keyword">ref</span> Node node)
{
<span class="d_comment">//Guaranteed to be string as we construct from scalar.
</span> <span class="d_comment">//!mystruct x:y:z
</span> <span class="d_keyword">auto</span> parts = node.get!string().split(<span class="d_string">":"</span>);
<span class="d_keyword">try</span>
{
<span class="d_keyword">return</span> MyStruct(to!<span class="d_keyword">int</span>(parts[0]), to!<span class="d_keyword">int</span>(parts[1]), to!<span class="d_keyword">int</span>(parts[2]));
}
<span class="d_keyword">catch</span>(Exception e)
{
<span class="d_keyword">throw</span> <span class="d_keyword">new</span> ConstructorException(<span class="d_string">"Could not construct MyStruct: "</span> ~ e.msg,
start, end);
}
}
<span class="d_keyword">void</span> main()
{
<span class="d_keyword">auto</span> loader = Loader(<span class="d_string">"file.yaml"</span>);
<span class="d_keyword">auto</span> constructor = <span class="d_keyword">new</span> Constructor;
constructor.<span class="d_psymbol">addConstructorScalar</span>(<span class="d_string">"!mystruct"</span>, &amp;constructMyStructScalar);
loader.constructor = constructor;
Node node = loader.load();
}
</pre>
</p>
</dd>
<dt class="d_decl">void <a name="addConstructorSequence"></a><span class="ddoc_psymbol">addConstructorSequence</span>(T)(in string <b>tag</b>, T function(Mark, Mark, ref Node) <b>ctor</b>);
</dt>
<dd><p>Add a constructor function from sequence.
</p>
<b>See Also:</b><div class="pbr">addConstructorScalar
</div>
<p><b>Example:</b><br>
<pre class="d_code"> <span class="d_keyword">import</span> std.string;
<span class="d_keyword">import</span> yaml;
<span class="d_keyword">struct</span> MyStruct
{
<span class="d_keyword">int</span> x, y, z;
}
MyStruct constructMyStructSequence(Mark start, Mark end, <span class="d_keyword">ref</span> Node node)
{
<span class="d_comment">//node is guaranteed to be sequence.
</span> <span class="d_comment">//!mystruct [x, y, z]
</span> <span class="d_keyword">try</span>
{
<span class="d_keyword">return</span> MyStruct(node[0].get!<span class="d_keyword">int</span>, node[1].get!<span class="d_keyword">int</span>, node[2].get!<span class="d_keyword">int</span>);
}
<span class="d_keyword">catch</span>(NodeException e)
{
<span class="d_keyword">throw</span> <span class="d_keyword">new</span> ConstructorException(<span class="d_string">"Could not construct MyStruct: "</span> ~ e.msg,
start, end);
}
}
<span class="d_keyword">void</span> main()
{
<span class="d_keyword">auto</span> loader = Loader(<span class="d_string">"file.yaml"</span>);
<span class="d_keyword">auto</span> constructor = <span class="d_keyword">new</span> Constructor;
constructor.<span class="d_psymbol">addConstructorSequence</span>(<span class="d_string">"!mystruct"</span>, &amp;constructMyStructSequence);
loader.constructor = constructor;
Node node = loader.load();
}
</pre>
</p>
</dd>
<dt class="d_decl">void <a name="addConstructorMapping"></a><span class="ddoc_psymbol">addConstructorMapping</span>(T)(in string <b>tag</b>, T function(Mark, Mark, ref Node) <b>ctor</b>);
</dt>
<dd><p>Add a constructor function from a mapping.
</p>
<b>See Also:</b><div class="pbr">addConstructorScalar
</div>
<p><b>Example:</b><br>
<pre class="d_code"> <span class="d_keyword">import</span> std.string;
<span class="d_keyword">import</span> yaml;
<span class="d_keyword">struct</span> MyStruct
{
<span class="d_keyword">int</span> x, y, z;
}
MyStruct constructMyStructMapping(Mark start, Mark end, <span class="d_keyword">ref</span> Node node)
{
<span class="d_comment">//node is guaranteed to be mapping.
</span> <span class="d_comment">//!mystruct {"x": x, "y": y, "z": z}
</span> <span class="d_keyword">try</span>
{
<span class="d_keyword">return</span> MyStruct(node[<span class="d_string">"x"</span>].get!<span class="d_keyword">int</span>, node[<span class="d_string">"y"</span>].get!<span class="d_keyword">int</span>, node[<span class="d_string">"z"</span>].get!<span class="d_keyword">int</span>);
}
<span class="d_keyword">catch</span>(NodeException e)
{
<span class="d_keyword">throw</span> <span class="d_keyword">new</span> ConstructorException(<span class="d_string">"Could not construct MyStruct: "</span> ~ e.msg,
start, end);
}
}
<span class="d_keyword">void</span> main()
{
<span class="d_keyword">auto</span> loader = Loader(<span class="d_string">"file.yaml"</span>);
<span class="d_keyword">auto</span> constructor = <span class="d_keyword">new</span> Constructor;
constructor.<span class="d_psymbol">addConstructorMapping</span>(<span class="d_string">"!mystruct"</span>, &amp;constructMyStructMapping);
loader.constructor = constructor;
Node node = loader.load();
}
</pre>
</p>
</dd>
</dl>
</dd>
<dt class="d_decl">YAMLNull <a name="constructNull"></a><span class="ddoc_psymbol">constructNull</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a <b>null</b> <b>node</b>.</p>
</dd>
<dt class="d_decl">YAMLMerge <a name="constructMerge"></a><span class="ddoc_psymbol">constructMerge</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a merge <b>node</b> - a <b>node</b> that merges another <b>node</b> into a mapping.</p>
</dd>
<dt class="d_decl">bool <a name="constructBool"></a><span class="ddoc_psymbol">constructBool</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a boolean <b>node</b>.</p>
</dd>
<dt class="d_decl">long <a name="constructLong"></a><span class="ddoc_psymbol">constructLong</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct an integer (long) <b>node</b>.</p>
</dd>
<dt class="d_decl">real <a name="constructReal"></a><span class="ddoc_psymbol">constructReal</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a floating point (real) <b>node</b>.</p>
</dd>
<dt class="d_decl">ubyte[] <a name="constructBinary"></a><span class="ddoc_psymbol">constructBinary</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a binary (base64) <b>node</b>.</p>
</dd>
<dt class="d_decl">SysTime <a name="constructTimestamp"></a><span class="ddoc_psymbol">constructTimestamp</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a timestamp (SysTime) <b>node</b>.</p>
</dd>
<dt class="d_decl">string <a name="constructString"></a><span class="ddoc_psymbol">constructString</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a string <b>node</b>.</p>
</dd>
<dt class="d_decl">Pair[] <a name="getPairs"></a><span class="ddoc_psymbol">getPairs</span>(string <b>type</b>, Mark <b>start</b>, Mark <b>end</b>, Node[] <b>nodes</b>);
</dt>
<dd><p>Convert a sequence of single-element mappings into a sequence of pairs.</p>
</dd>
<dt class="d_decl">Pair[] <a name="constructOrderedMap"></a><span class="ddoc_psymbol">constructOrderedMap</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct an ordered map (ordered sequence of key:value pairs without duplicates) <b>node</b>.</p>
</dd>
<dt class="d_decl">Pair[] <a name="constructPairs"></a><span class="ddoc_psymbol">constructPairs</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a pairs (ordered sequence of key: value pairs allowing duplicates) <b>node</b>.</p>
</dd>
<dt class="d_decl">Node[] <a name="constructSet"></a><span class="ddoc_psymbol">constructSet</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a set <b>node</b>.</p>
</dd>
<dt class="d_decl">Node[] <a name="constructSequence"></a><span class="ddoc_psymbol">constructSequence</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct a sequence (array) <b>node</b>.</p>
</dd>
<dt class="d_decl">Pair[] <a name="constructMap"></a><span class="ddoc_psymbol">constructMap</span>(Mark <b>start</b>, Mark <b>end</b>, ref Node <b>node</b>);
</dt>
<dd><p>Construct an unordered map (unordered set of key: value pairs without duplicates) <b>node</b>.</p>
</dd>
</dl>
</div>
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Copyright &copy; Ferdinand Majerech 2011. Based on <a href="http://www.pyyaml.org">PyYAML</a> by Kirill Simonov. |
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