protected override bool NondestructiveUnify(FeatureValue other, bool useDefaults, IDictionary <FeatureValue, FeatureValue> copies,
VariableBindings varBindings, out FeatureValue output)
{
FeatureStruct otherFS;
if (!Dereference(other, out otherFS))
{
output = null;
return(false);
}
var copy = new FeatureStruct();
copies[this] = copy;
copies[other] = copy;
foreach (KeyValuePair <Feature, FeatureValue> featVal in otherFS._definite)
{
FeatureValue otherValue = Dereference(featVal.Value);
FeatureValue thisValue;
if (_definite.TryGetValue(featVal.Key, out thisValue))
{
thisValue = Dereference(thisValue);
FeatureValue newValue;
if (!thisValue.UnifyImpl(otherValue, useDefaults, copies, varBindings, out newValue))
{
output = null;
return(false);
}
copy.AddValue(featVal.Key, newValue);
}
else if (useDefaults && featVal.Key.DefaultValue != null)
{
thisValue = featVal.Key.DefaultValue.DeepCloneImpl(null);
FeatureValue newValue;
if (!thisValue.UnifyImpl(otherValue, true, copies, varBindings, out newValue))
{
output = null;
return(false);
}
copy._definite[featVal.Key] = newValue;
}
else
{
copy._definite[featVal.Key] = otherValue.DeepCloneImpl(copies);
}
}
foreach (KeyValuePair <Feature, FeatureValue> featVal in _definite)
{
if (!otherFS._definite.ContainsKey(featVal.Key))
{
copy._definite[featVal.Key] = Dereference(featVal.Value).DeepCloneImpl(copies);
}
}
output = copy;
return(true);
}
internal override bool DestructiveUnify(FeatureValue other, bool useDefaults, bool preserveInput,
IDictionary <FeatureValue, FeatureValue> copies, VariableBindings varBindings)
{
FeatureStruct otherFS;
if (!Dereference(other, out otherFS))
{
return(false);
}
if (this == otherFS)
{
return(true);
}
if (preserveInput)
{
if (copies != null)
{
copies[otherFS] = this;
}
}
else
{
otherFS.Forward = this;
}
foreach (KeyValuePair <Feature, FeatureValue> featVal in otherFS._definite)
{
FeatureValue otherValue = Dereference(featVal.Value);
FeatureValue thisValue;
if (_definite.TryGetValue(featVal.Key, out thisValue))
{
thisValue = Dereference(thisValue);
if (!thisValue.DestructiveUnify(otherValue, useDefaults, preserveInput, copies, varBindings))
{
return(false);
}
}
else if (useDefaults && featVal.Key.DefaultValue != null)
{
thisValue = featVal.Key.DefaultValue.DeepCloneImpl(null);
_definite[featVal.Key] = thisValue;
if (!thisValue.DestructiveUnify(otherValue, true, preserveInput, copies, varBindings))
{
return(false);
}
}
else
{
_definite[featVal.Key] = preserveInput ? otherValue.DeepCloneImpl(copies) : otherValue;
}
}
return(true);
}
private void PriorityUnion(FeatureStruct other, VariableBindings varBindings, IDictionary <FeatureValue, FeatureValue> copies)
{
other = Dereference(other);
copies[other] = this;
foreach (KeyValuePair <Feature, FeatureValue> featVal in _definite)
{
FeatureValue thisValue = Dereference(featVal.Value);
FeatureValue otherValue;
if (other._definite.TryGetValue(featVal.Key, out otherValue))
{
otherValue = Dereference(otherValue);
var otherFS = otherValue as FeatureStruct;
if (otherFS != null && !copies.ContainsKey(otherFS))
{
var thisFS = thisValue as FeatureStruct;
if (thisFS != null)
{
thisFS.PriorityUnion(otherFS, varBindings, copies);
}
}
}
}
foreach (KeyValuePair <Feature, FeatureValue> featVal in other._definite)
{
FeatureValue otherValue = Dereference(featVal.Value);
FeatureValue thisValue;
if (_definite.TryGetValue(featVal.Key, out thisValue))
{
otherValue = Dereference(otherValue);
var otherFS = otherValue as FeatureStruct;
if (otherFS != null)
{
if (thisValue is FeatureStruct)
{
FeatureValue reentrant;
if (copies.TryGetValue(otherFS, out reentrant))
{
_definite[featVal.Key] = reentrant;
}
}
else
{
_definite[featVal.Key] = otherFS.DeepCloneImpl(copies);
}
}
else
{
var otherSfv = (SimpleFeatureValue)otherValue;
SimpleFeatureValue binding;
if (otherSfv.IsVariable && varBindings.TryGetValue(otherSfv.VariableName, out binding))
{
_definite[featVal.Key] = binding.GetVariableValue(otherSfv.Agree);
}
else
{
_definite[featVal.Key] = otherSfv.DeepCloneImpl(copies);
}
}
}
else
{
_definite[featVal.Key] = otherValue.DeepCloneImpl(copies);
}
}
}