public static int Compare(StemmingRule a, StemmingRule b)
{
// primary: decreasing by prio
int result = b._Priority - a._Priority;
if (result == 0)
{
// secondary: decreasing by length
result = b._Length - a._Length;
}
return(result);
}
public void Add(StemmingRule r)
{
_Rules.Add(r);
Sort();
}
/// <summary>
/// Read a stemming _Rule from a string in the old TRADOS format.
/// </summary>
/// <param name="rule">The textual _Rule</param>
/// <returns>A new stemming _Rule, parsed from the input string</returns>
public void Add(string rule)
{
_Rule = rule;
_RuleP = 0;
StemmingRule result = new StemmingRule();
int state = 0;
int len = _Rule.Length;
while (state != 99)
{
while (_RuleP < len && System.Char.IsWhiteSpace(_Rule, _RuleP))
{
++_RuleP;
}
switch (state)
{
case 0:
// waiting for initial keyword
switch (GetIdentifier().ToLowerInvariant())
{
case "replace":
state = 6;
break;
case "stripdiacritics":
state = 1;
result.Action = StemmingRule.StemAction.StripDiacritics;
break;
case "tolower":
result.Action = StemmingRule.StemAction.MapToLower;
state = 1;
break;
case "deletelastdoublevowels":
result.Action = StemmingRule.StemAction.DeleteLastDoubleVowels;
state = 1;
break;
case "deletelastdoubleconsonants":
result.Action = StemmingRule.StemAction.DeleteLastDoubleConsonants;
state = 1;
break;
case "testonbaseword":
result.Action = StemmingRule.StemAction.TestOnBaseWord;
state = 1;
break;
case "set":
// Variable Setting
state = 12;
break;
default:
throw new Core.LanguagePlatformException(Core.ErrorCode.SegmentationIllegalKeywordInRule, _Rule);
}
break;
case 1:
// priority...
Expect("priority");
state = 2;
break;
case 2:
// priority number
result.Priority = GetNumber();
state = 3;
break;
case 3:
// "and"
Expect("and");
state = 4;
break;
case 4:
// "restart" - continuation
state = 10;
switch (GetIdentifier().ToLowerInvariant())
{
case "continue":
result.ContinuationOnSuccess = StemmingRule.StemContinuation.Continue;
break;
case "restart":
result.ContinuationOnSuccess = StemmingRule.StemContinuation.Restart;
break;
case "stop":
result.ContinuationOnSuccess = StemmingRule.StemContinuation.Stop;
state = 5; // no continuation priority for stop
break;
default:
throw new Core.LanguagePlatformException(Core.ErrorCode.SegmentationIllegalContinuation, _Rule);
}
result.ContinuationOnFail = StemmingRule.StemContinuation.Continue;
result.ContinuationPriority = 0;
break;
case 5:
// final semicolon
if (_Rule[_RuleP] == ';')
{
state = 99; // success
}
else
{
throw new Core.LanguagePlatformException(Core.ErrorCode.SegmentationTrailingJunk, _Rule);
}
break;
case 6:
// _Rule/affix type
switch (GetIdentifier().ToLowerInvariant())
{
case "prefix":
result.Action = StemmingRule.StemAction.Prefix;
break;
case "suffix":
result.Action = StemmingRule.StemAction.Suffix;
break;
case "infix":
result.Action = StemmingRule.StemAction.Infix;
break;
case "properinfix":
result.Action = StemmingRule.StemAction.ProperInfix;
break;
case "circumfix":
result.Action = StemmingRule.StemAction.Circumfix;
break;
case "form":
result.Action = StemmingRule.StemAction.Form;
break;
case "prefixedinfix":
result.Action = StemmingRule.StemAction.PrefixedInfix;
break;
default:
throw new Core.LanguagePlatformException(Core.ErrorCode.SegmentationUnknownRuleType, _Rule);
}
state = 7;
break;
case 7:
// affix pattern
result.Affix = GetQuotedString();
state = 8;
break;
case 8:
// "with"
Expect("with");
state = 9;
break;
case 9:
// replacement pattern
result.Replacement = GetQuotedString();
state = 1;
break;
case 10:
// "at" <cprio>
if (_Rule[_RuleP] == ';')
{
state = 5;
}
else
{
Expect("at");
state = 11;
}
break;
case 11:
result.ContinuationPriority = GetNumber();
state = 5;
break;
case 12: // Variable Setting - got "set", expect variable name
{
string id = GetIdentifier().ToLowerInvariant();
switch (id)
{
case "minwordlength":
_RuleSet.MinimumWordLength = GetNumber();
break;
case "minstemlength":
_RuleSet.MinimumStemLength = GetNumber();
break;
case "minstempercentage":
_RuleSet.MinimumStemPercentage = GetNumber();
break;
case "maxruleapplications":
_RuleSet.MaximumRuleApplications = GetNumber();
break;
default:
throw new Core.LanguagePlatformException(Core.ErrorCode.SegmentationInvalidVariableName, id);
}
state = 5;
}
break;
}
}
if (result != null && result.Action != StemmingRule.StemAction.None)
{
_RuleSet.Add(result);
}
}
private bool ApplyRule(ref string form, int shortestStemLength, bool specialRulesOnly,
StemmingRule rule)
{
int patternLength = String.IsNullOrEmpty(rule.Affix) ? 0 : rule.Affix.Length;
int wordLength = form.Length;
int replacementLength = String.IsNullOrEmpty(rule.Replacement) ? 0 : rule.Replacement.Length;
bool result = false;
// we allow that the pattern length is equal to the word length,
// in order to support substitutions such as "went"/Prefix->"go"
// special rules (tolower, tobase) are always executed, no matter
// whether the minwordlength is below the original length.
if (rule.Action == StemmingRule.StemAction.MapToLower)
{
form = form.ToLowerInvariant();
result = true;
}
else if (rule.Action == StemmingRule.StemAction.StripDiacritics)
{
form = Core.CharacterProperties.ToBase(form);
form = StripPeripheralPunctuation(form);
result = true;
}
else if (specialRulesOnly)
{
result = false;
}
else if (rule.Action == StemmingRule.StemAction.TestOnBaseWord)
{
result = _Resources.IsStopword(form);
}
else if (rule.Action == StemmingRule.StemAction.DeleteLastDoubleConsonants)
{
if (wordLength > 2)
{
for (int charPos = wordLength - 1; charPos > 0; --charPos)
{
if (form[charPos] == form[charPos - 1] && !Core.CharacterProperties.IsVowel(form[charPos]))
{
form = form.Remove(charPos);
break;
}
}
}
result = true;
}
else if (rule.Action == StemmingRule.StemAction.DeleteLastDoubleVowels)
{
if (wordLength > 2)
{
for (int charPos = wordLength - 1; charPos > 0; --charPos)
{
if (form[charPos] == form[charPos - 1] && Core.CharacterProperties.IsVowel(form[charPos]))
{
form = form.Remove(charPos);
break;
}
}
}
result = true;
}
else if (wordLength < patternLength)
{
result = false;
}
else if (wordLength - patternLength + replacementLength < shortestStemLength)
{
// Don't let result string become too short
result = false;
}
else
{
result = ReplaceAffix(ref form, rule.Action, rule.Affix, rule.Replacement);
}
return(result);
}
