public SimpleName(string description)
{
this.literals = new List <Literal>();
this.isGrounded = true;
description = description.RemoveWhiteSpace();
var n = Name.BuildName(description); //Substituir
if (n.IsComposed)
{
char[] literalLimiterChars = { ' ', ',', '(', ')' };
string[] stringLiterals = description.Split(literalLimiterChars, StringSplitOptions.RemoveEmptyEntries);
var lPos = 0;
var depth = 0;
for (int i = 0; i < description.Length; i++)
{
//add literal
Literal lit = null;
switch (description[i])
{
case '(':
this.literals.Add(new Literal(stringLiterals[lPos], LiteralType.Root, depth));
lPos++;
depth++;
break;
case ',':
if (description[i - 1] != ')')
{
this.literals.Add(new Literal(stringLiterals[lPos], LiteralType.Param, depth));
lPos++;
}
break;
case ')':
if (description[i - 1] != ')')
{
this.literals.Add(new Literal(stringLiterals[lPos], LiteralType.Param, depth));
lPos++;
}
depth--;
break;
}
}
}
else //if n is non composed
{
this.literals.Add(new Literal(description, LiteralType.Param, 0));
}
//check if grounded
foreach (var l in this.literals)
{
if (SimpleWFN.IsVariable(l))
{
this.isGrounded = false;
}
}
}
public SimpleName(IEnumerable <Literal> literalList)
{
this.literals = new List <Literal>();
this.isGrounded = true;
// used to reset the depth of the first literal to 0
var delta = literalList.FirstOrDefault().depth;
foreach (var l in literalList)
{
this.literals.Add(new Literal(l.description, l.type, l.depth - delta));
if (SimpleWFN.IsVariable(l))
{
this.isGrounded = false;
}
}
}
//return the idx jump on the valName or -1 if it can't add the substitution
private static int FindSubsAux(Literal var, Literal val, SimpleName valName, IDictionary <string, Substitution> bindings)
{
//first, analyse if the value is a composed name or a single parameter
string valDescription;
int valLiteralCount;
if (val.type == LiteralType.Root)
{
SimpleName auxName = null;
auxName = SimpleWFN.BuildNameFromContainedLiteral(valName, val);
valDescription = auxName.ToString();
valLiteralCount = auxName.literals.Count;
}
else
{
valDescription = val.description;
valLiteralCount = 1;
}
//check if a binding for the same variable already exists
Substitution existingSub = null;
bindings.TryGetValue(var.description, out existingSub);
if (existingSub != null)
{
if (existingSub.SubValue.ToString().RemoveWhiteSpace().EqualsIgnoreCase(valDescription))
{
return(valLiteralCount);
}
else
{
return(-1);
}
}
//if there was no existing binding to the variable
try
{
bindings[var.description] = new Substitution(var.description, valDescription);
return(valLiteralCount);
}
catch (BadSubstitutionException)
{
return(-1);
}
}
/// <summary>
/// Unifying Method, receives two WellFormedNames and tries
/// to find a list of Substitutions that will make
/// both names syntatically equal. The algorithm performs Occur Check,
/// as such the unification of [X] and Luke([X]) will allways fail.
///
/// The method goes on each symbol (for both names) at a time, and tries to find
/// a substitution between them. Take into account that the Unification between
/// [X](John,Paul) and Friend(John,[X]) fails because the algorithm considers [X]
/// to be the same variable
/// </summary>
/// <see cref="FAtiMA.Core.WellFormedNames.Substitution"/>
/// <see cref="FAtiMA.Core.WellFormedNames.Name"/>
/// <param name="name1">The first Name</param>
/// <param name="name2">The second Name</param>
/// <param name="bindings">The out paramenter for the founded substitutions</param>
/// <returns>True if the names are unifiable, in this case the bindings list will contain the found Substitutions, otherwise it will be empty</returns>
public static bool Unify(SimpleName name1, SimpleName name2, out IEnumerable <Substitution> bindings)
{
bindings = null;
if (name1 == null || name2 == null)
{
return(false);
}
if (SimpleWFN.IsGrounded(name1) && SimpleWFN.IsGrounded(name2))
{
if (SimpleWFN.Match(name1, name2))
{
bindings = Enumerable.Empty <Substitution>();
return(true);
}
else
{
return(false);
}
}
bindings = FindSubst(name1, name2);
return(bindings != null);
}
private static IEnumerable <Substitution> FindSubst(SimpleName n1, SimpleName n2)
{
// SubstitutionSet bindings = new SubstitutionSet();
Dictionary <string, Substitution> bindings = new Dictionary <string, Substitution>();
var idx1 = 0;
var idx2 = 0;
do
{
var l1 = n1.literals[idx1];
var l2 = n2.literals[idx2];
//neither literal is a variable
if (!SimpleWFN.IsVariable(l1) && !SimpleWFN.IsVariable(l2))
{
if (l1.description.EqualsIgnoreCase(l2.description))
{
idx1++; idx2++;
continue;
}
else
{
return(null);
}
}
//both literals are a variable
if (SimpleWFN.IsVariable(l1) && SimpleWFN.IsVariable(l2))
{
if (!l1.description.EqualsIgnoreCase(l2.description))
{
if (bindings.ContainsKey(l1.description))
{
return(null);
}
bindings[l1.description] = new Substitution(l1.description, l2.description);
}
idx1++; idx2++;
continue;
}
//only l1 is a variable
if (SimpleWFN.IsVariable(l1) && !SimpleWFN.IsVariable(l2))
{
var res = FindSubsAux(l1, l2, n2, bindings);
if (res == -1)
{
return(null);
}
else
{
idx1++; idx2 += res; continue;
}
}
//only l2 is a variable
if (!SimpleWFN.IsVariable(l1) && SimpleWFN.IsVariable(l2))
{
var res = FindSubsAux(l2, l1, n1, bindings);
if (res == -1)
{
return(null);
}
else
{
idx1 += res; idx2++; continue;
}
}
throw new Exception("Unexpected Situation");
} while (idx1 < n1.literals.Count && idx2 < n2.literals.Count);
if (idx1 == n1.literals.Count && idx2 == n2.literals.Count)
{
return(bindings.Values); // full match
}
else
{
return(null); // only partial match
};
}
public static bool Match(SimpleName n1, SimpleName n2)
{
if (SimpleWFN.GetNumberOfTerms(n1) != SimpleWFN.GetNumberOfTerms(n2))
{
return(false);
}
var idx1 = 0;
var idx2 = 0;
do
{
var l1 = n1.literals[idx1];
var l2 = n2.literals[idx2];
//auxiliary variables
bool typesMatch = l1.type == l2.type;
bool l1IsUniv = l1.description == Name.UNIVERSAL_STRING;
bool l2IsUniv = l2.description == Name.UNIVERSAL_STRING;
bool existsUniversal = l1IsUniv || l2IsUniv;
//The easy matching scenario is when both types match
if (typesMatch)
{
if (existsUniversal || l1.description.EqualsIgnoreCase(l2.description))
{
idx1++; idx2++;
continue;
}
return(false); //no universals and different descritions
}
//eg. matching S with S(A)
if (!typesMatch && !existsUniversal)
{
return(false);
}
//l1 is a universal and l2 has a different type
if (!typesMatch && l1IsUniv)
{
//l1 is a universal parameter and n2 is a root
if (l1.type == LiteralType.Param)
{
// the index on n2 must jump until it reaches the depth of l1 again
idx2 += FindJumpUntilDepthN(n2.literals, idx2, l1.depth);
idx1++;
continue;
}
//a root universal never matches any parameter except a universal
if (l1.type == LiteralType.Root && !l2IsUniv)
{
return(false);
}
}
//the last case is when l2 is the universal
if (!typesMatch && l2IsUniv)
{
if (l2.type == LiteralType.Param)
{
// the index on n2 must jump until it reaches the depth of n1 again
idx1 += FindJumpUntilDepthN(n1.literals, idx1, l2.depth);
idx2++;
continue;
}
//a root universal never matches any parameter except a universal
if (l2.type == LiteralType.Root && !l1IsUniv)
{
return(false);
}
}
} while (idx1 < n1.literals.Count && idx2 < n2.literals.Count);
if (idx1 == n1.literals.Count && idx2 == n2.literals.Count)
{
return(true); // full match
}
else
{
return(false); // only partial match
}
}
