Clean up StructureTerm
- Remove commented out code;
- Drop duplicate "arity" field and use args.length instead;
- Add common String, Term[] constructor to simplify construction
diff --git a/src/lang/StructureTerm.java b/src/lang/StructureTerm.java
index ef806cf..e1d8ea8 100644
--- a/src/lang/StructureTerm.java
+++ b/src/lang/StructureTerm.java
@@ -27,8 +27,14 @@
/** Holds the argument terms of this <code>StructureTerm</code>. */
protected Term[] args;
- /** Holds the arity of this <code>StructureTerm</code>. */
- protected int arity;
+ /**
+ * Constructs a new Prolog compound term
+ * such that <code>name</code> is the functor symbol, and
+ * <code>args</code> is the argument terms respectively.
+ */
+ public StructureTerm(String name, Term... args){
+ this(SymbolTerm.makeSymbol(name, args.length), args);
+ }
/**
* Constructs a new Prolog compound term
@@ -36,11 +42,10 @@
* <code>_args</code> is the argument terms respectively.
*/
public StructureTerm(SymbolTerm _functor, Term... _args){
- functor = _functor;
- arity = functor.arity();
- args = _args;
- if (arity != args.length)
+ if (_functor.arity() != _args.length)
throw new InternalException("Invalid argument length in StructureTerm");
+ functor = _functor;
+ args = _args;
}
/** Returns the functor symbol of this <code>StructureTerm</code>.
@@ -53,7 +58,7 @@
* @return the value of <code>arity</code>.
* @see #arity
*/
- public int arity(){ return arity; }
+ public int arity(){ return args.length; }
/** Returns the argument terms of this <code>StructureTerm</code>.
* @return the value of <code>args</code>.
@@ -68,22 +73,6 @@
*/
public String name(){ return functor.name(); }
- /* Term
- public boolean unify(Term t, Trail trail) {
- if (t.isVariable())
- return t.unify(this, trail);
- if (! t.isStructure())
- return false;
- if (! functor.equals(((StructureTerm)t).functor()))
- return false;
- for (int i=0; i<arity; i++) {
- if (! args[i].unify(((StructureTerm)t).args[i], trail))
- return false;
- }
- return true;
- } */
-
-
public boolean unify(Term t, Trail trail) {
t = t.dereference();
if (t.isVariable()) {
@@ -94,27 +83,22 @@
return false;
if (! functor.equals(((StructureTerm)t).functor()))
return false;
- for (int i=0; i<arity; i++) {
+ for (int i=0; i<args.length; i++) {
if (! args[i].unify(((StructureTerm)t).args[i], trail))
return false;
}
return true;
}
- // public boolean unify(Term t, Trail trail) {
- // return trail.engine.unify(this, t);
- // }
-
-
protected Term copy(Prolog engine) {
- Term[] a = new Term[arity];
- for (int i=0; i<arity; i++)
+ Term[] a = new Term[args.length];
+ for (int i=0; i<args.length; i++)
a[i] = args[i].copy(engine);
return new StructureTerm(functor, a);
}
public boolean isGround() {
- for (int i=0; i<arity; i++) {
+ for (int i=0; i<args.length; i++) {
if (! args[i].isGround())
return false;
}
@@ -124,7 +108,7 @@
public String toQuotedString() {
String delim = "";
String s = functor.toQuotedString() + "(";
- for (int i=0; i<arity; i++) {
+ for (int i=0; i<args.length; i++) {
s += delim + args[i].toQuotedString();
delim = ",";
}
@@ -148,7 +132,7 @@
return false;
if (! functor.equals(((StructureTerm)obj).functor()))
return false;
- for (int i=0; i<arity; i++) {
+ for (int i=0; i<args.length; i++) {
if (! args[i].equals(((StructureTerm)obj).args[i].dereference()))
return false;
}
@@ -158,7 +142,7 @@
public int hashCode() {
int h = 1;
h = 31*h + functor.hashCode();
- for(int i=0; i<arity; i++)
+ for(int i=0; i<args.length; i++)
h = 31*h + args[i].dereference().hashCode();
return h;
}
@@ -167,7 +151,7 @@
public String toString() {
String delim = "";
String s = functor.toString() + "(";
- for (int i=0; i<arity; i++) {
+ for (int i=0; i<args.length; i++) {
s += delim + args[i].toString();
delim = ",";
}
@@ -193,23 +177,25 @@
if (anotherTerm.isVariable() || anotherTerm.isNumber() || anotherTerm.isSymbol())
return AFTER;
if (anotherTerm.isList()) {
+ ListTerm t = (ListTerm)anotherTerm;
functor2 = ListTerm.SYM_DOT;
args2 = new Term[2];
- args2[0] = ((ListTerm)anotherTerm).car();
- args2[1] = ((ListTerm)anotherTerm).cdr();
+ args2[0] = t.car();
+ args2[1] = t.cdr();
arity2 = 2;
} else if (anotherTerm.isStructure()) {
- functor2 = ((StructureTerm)anotherTerm).functor();
- args2 = ((StructureTerm)anotherTerm).args();
- arity2 = ((StructureTerm)anotherTerm).arity();
+ StructureTerm s = (StructureTerm)anotherTerm;
+ functor2 = s.functor();
+ args2 = s.args();
+ arity2 = s.arity();
} else {
return BEFORE;
}
- if (arity != arity2)
- return (arity - arity2);
+ if (args.length != arity2)
+ return (args.length - arity2);
if (! functor.equals(functor2))
return functor.compareTo(functor2);
- for (int i=0; i<arity; i++) {
+ for (int i=0; i<args.length; i++) {
rc = args[i].compareTo(args2[i].dereference());
if (rc != EQUAL)
return rc;
