Split MATCH into MATCH/2 and MATCH_TO/3

The result often isn't needed.

check-docs.py

@@ -21,7 +21,8 @@ def parse_dl(path):
 parse_dl(os.path.join(dldir, 'base.sam'))
 
 declared.add("ASSIGN(String Type, Object value, Type result)")
-declared.add("MATCH(Object a, Object b, Object result)")
+declared.add("MATCH(Object a, Object b)")
+declared.add("MATCH_TO(Object a, Object b, Object result)")
 documented.add("NOT_EQUAL(Object a, Object b)")
 
 undocumented = declared - documented

doc/base.rst

@@ -150,14 +150,15 @@ These are not relations, so you can't enumerate all their values, but you can us
 	ASSIGN("String", any(Value)) -> any(String)
 	ASSIGN("String", any(int)) -> nothing
 
-.. function:: MATCH(Object a, Object b, Object result)
+.. function:: MATCH(Object a, Object b)
+.. function:: MATCH_TO(Object a, Object b, Object result)
 
-   Tests whether `a = b`, taking account of the fact that either may be an `any` value. The `result` is the intersection
+   Tests whether `a = b`, taking account of the fact that either may be an `any` value. The `result` (in the three-argument form) is the intersection
    of the possible values. e.g.::
 
-       MATCH("foo", "foo") -> "foo"
-       MATCH("foo", "bar") -> nothing
-       MATCH(any(String), any(Value)) -> any(String)
+       MATCH_TO("foo", "foo") -> "foo"
+       MATCH_TO("foo", "bar") -> nothing
+       MATCH_TO(any(String), any(Value)) -> any(String)
 
 .. function:: MAKE_OBJECT(String nameHint, String invocation, Ref child)
 

doc/examples/includes/rbacTabs.sam

@@ -30,7 +30,7 @@ declare hasRole(Ref object, Ref target, String role).
 hasRole(?Object, ?Target, ?Role) :-
     hasIdentity(?Object, ?Identity1),
     grantsRole(?Target, ?Role, ?Identity2),
-    MATCH(?Identity1, ?Identity2, ?Identity).       // (may grant to any(String))
+    MATCH(?Identity1, ?Identity2).       // (may grant to any(String))
 
 guiObjectTab(50, "Has roles", "hasRole/3", "object").
 guiObjectTab(60, "Grants roles", "grantsRole/3", "target").

src/main/java/eu/serscis/sam/Constants.java

@@ -37,7 +37,8 @@
 
 public class Constants {
 	static public IPredicate ASSIGNP = BASIC.createPredicate("ASSIGN", 3);
-	static public IPredicate MATCHP = BASIC.createPredicate("MATCH", 3);
+	static public IPredicate MATCH2P = BASIC.createPredicate("MATCH", 2);
+	static public IPredicate MATCH_TOP = BASIC.createPredicate("MATCH_TO", 3);
 	static public IPredicate EQUALP = BASIC.createPredicate("EQUAL", 2);
 	static public IPredicate accessControlOnP = BASIC.createPredicate("accessControlOn", 0);
 	static public IPredicate expectFailureP = BASIC.createPredicate("expectFailure", 0);

src/main/java/eu/serscis/sam/Eval.java

@@ -62,7 +62,7 @@ public IRule process(IRule rule) throws RuleUnsafeException {
 				for (ILiteral lit : rule.getBody()) {
 					String p = lit.getAtom().getPredicate().getPredicateSymbol();
 					if (p.equals("TO_STRING") || p.equals("STRING_CONCAT") ||
-					    p.equals("MAKE_OBJECT") || p.equals("MATCH") || p.equals("ASSIGN")) {
+					    p.equals("MAKE_OBJECT") || p.equals("MATCH_TO") || p.equals("ASSIGN")) {
 						return rule;
 					}
 				}

src/main/java/eu/serscis/sam/MatchBuiltin.java

@@ -28,6 +28,7 @@
 
 package eu.serscis.sam;
 
+import org.deri.iris.builtins.BooleanBuiltin;
 import static org.deri.iris.factory.Factory.BASIC;
 
 import org.deri.iris.EvaluationException;
@@ -40,21 +41,25 @@
 
 public class MatchBuiltin extends FunctionalBuiltin {
 
-	private static final String PREDICATE_STRING = "MATCH";
-	private static final IPredicate PREDICATE = BASIC.createPredicate(PREDICATE_STRING, -1);
+	private static final String PREDICATE_STRING = "MATCH_TO";
+	private static final IPredicate PREDICATE = Constants.MATCH_TOP;
 
 	public MatchBuiltin(ITerm... terms) {
 		super(BASIC.createPredicate(PREDICATE_STRING, terms.length), terms);
 
-		if (terms.length < 2 || terms.length > 3) {
-			throw new IllegalArgumentException("The amount of terms <" + terms.length + "> must be 2 or 3");
+		if (terms.length != 3) {
+			throw new IllegalArgumentException("The amount of terms <" + terms.length + "> must be 3");
 		}
 	}
 
 	protected ITerm computeResult(ITerm[] terms) throws EvaluationException {
-		ITerm first = terms[0];
-		ITerm second = terms[1];
+		if (terms.length != 3) {
+			throw new IllegalArgumentException("The amount of terms <" + terms.length + "> must be 3");
+		}
+		return MatchBuiltin.computeResult(terms[0], terms[1]);
+	}
 
+	private static ITerm computeResult(ITerm first, ITerm second) throws EvaluationException {
 		ITerm result;
 
 		/* If both terms are not any(), they match only if they are equal.
@@ -75,7 +80,7 @@ protected ITerm computeResult(ITerm[] terms) throws EvaluationException {
 		return result;
 	}
 
-	private ITerm matchAny(AnyTerm any, ITerm other) {
+	private static ITerm matchAny(AnyTerm any, ITerm other) {
 		if (other instanceof AnyTerm) {
 			Type intersection = any.type.intersect(((AnyTerm) other).type);
 			if (intersection == null) {
@@ -92,4 +97,21 @@ private ITerm matchAny(AnyTerm any, ITerm other) {
 
 		return null;					// e.g. !MATCH(any(int), "hi", ?Result)
 	}
+
+	/* Two-argument form that just tests whether a match exists. */
+	public static class MatchBuiltinBoolean extends BooleanBuiltin {
+		private static final IPredicate PREDICATE = Constants.MATCH2P;
+
+		public MatchBuiltinBoolean(final ITerm... t) {
+			super(PREDICATE, t);
+		}
+
+		public boolean computeResult(ITerm[] terms) {
+			try {
+				return MatchBuiltin.computeResult(terms[0], terms[1]) != null;
+			} catch (EvaluationException ex) {
+				throw new RuntimeException(ex);
+			}
+		}
+	}
 }

src/main/java/eu/serscis/sam/Model.java

@@ -102,6 +102,7 @@ public class Model {
 		builtinRegister.registerBuiltin(new AssignBuiltin(t1, t2, t3));
 
 		builtinRegister.registerBuiltin(new MatchBuiltin(t1, t2, t3));
+		builtinRegister.registerBuiltin(new MatchBuiltin.MatchBuiltinBoolean(t1, t2));
 	}
 
 	public Model(Configuration configuration) {

src/main/java/eu/serscis/sam/TypeChecker.java

@@ -190,7 +190,9 @@ public void check(ILiteral lit, boolean head, List<Token> tokens) throws ParserE
 							new TermDefinition(Type.ObjectT)
 						};
 				}
-			} else if ((predicate.equals(Constants.EQUALP) || predicate.equals(Constants.MATCHP)) && !head) {
+			} else if ((predicate.equals(Constants.EQUALP) ||
+				    predicate.equals(Constants.MATCH2P) ||
+				    predicate.equals(Constants.MATCH_TOP)) && !head) {
 				updateTypesEqual(tuple, tokens);
 				return;
 			} else if ((predicate.getPredicateSymbol().equals("error")) && tuple.size() > 0) {

src/main/sam/groupBy.sam

@@ -49,10 +49,10 @@ didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?TargetInvocation, ?Meth
     maySend(?Caller, ?CallerInvocation, ?CallSite, ?SendPos, ?SentValue),
     hasParam(?Method, ?ParamType, ?AnyParam, ?ParamPos),
     ASSIGN(?ParamType, ?SentValue, ?ReceivedValue),
-    MATCH(?SendPos, ?ParamPos, ?DontCarePos),
+    MATCH(?SendPos, ?ParamPos),
     GroupByArgAt(?Method, ?ParamPos),
     GroupByArgCase(?Method, ?CaseValue, ?TargetInvocation),
-    MATCH(?ReceivedValue, ?CaseValue, ?DontCareValue).
+    MATCH(?ReceivedValue, ?CaseValue).
 
 didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?TargetContext, ?Method) :-
     didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?Method),
@@ -70,10 +70,10 @@ didReceive(?Target, ?TargetInvocation, ?Method, ?ParamPos, ?ReceivedMatchedValue
     maySend(?Caller, ?CallerInvocation, ?CallSite, ?SendPos, ?SentValue),
     hasParam(?Method, ?ParamType, ?AnyParam, ?ParamPos),
     ASSIGN(?ParamType, ?SentValue, ?ReceivedValue),
-    MATCH(?SendPos, ?ParamPos, ?DontCarePos),
+    MATCH(?SendPos, ?ParamPos),
     GroupByArgAt(?Method, ?ParamPos),
     GroupByArgCase(?Method, ?CaseValue, ?TargetInvocation),
-    MATCH(?ReceivedValue, ?CaseValue, ?ReceivedMatchedValue).
+    MATCH_TO(?ReceivedValue, ?CaseValue, ?ReceivedMatchedValue).
 
 // the other args
 
@@ -82,14 +82,14 @@ didReceive(?Target, ?TargetInvocation, ?Method, ?ParamPos, ?ReceivedValue) :-
     maySend(?Caller, ?CallerInvocation, ?CallSite, ?SendPos, ?SentValue),
     hasParam(?Method, ?ParamType, ?AnyParam, ?ParamPos),
     ASSIGN(?ParamType, ?SentValue, ?ReceivedValue),
-    MATCH(?SendPos, ?ParamPos, ?DontCarePos),
+    MATCH(?SendPos, ?ParamPos),
     GroupByArgAt(?Method, ?GroupByArgAt), ?GroupByArgAt != ?ParamPos.
 
 error("missing GroupByArgCase", ?Method, ?ReceivedValue) :- 
     GroupByArgAt(?Method, ?ParamPos),
     didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?Method),
     maySend(?Caller, ?CallerInvocation, ?CallSite, ?SendPos, ?SentValue),
-    MATCH(?SendPos, ?ParamPos, ?DontCarePos),
+    MATCH(?SendPos, ?ParamPos),
     hasParam(?Method, ?ParamType, ?AnyParam, ?ParamPos),
     ASSIGN(?ParamType, ?SentValue, ?ReceivedValue),
     !didReceive(?Target, ?TargetInvocation, ?Method, ?ParamPos, ?ReceivedValue).
@@ -128,7 +128,7 @@ didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?TargetContext, ?Method)
 didReceive(?Target, ?TargetInvocation, ?Method, ?ParamPos, ?ReceivedValue) :-
 	didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?TargetInvocation, ?Method),
 	maySend(?Caller, ?CallerInvocation, ?CallSite, ?SendPos, ?SentValue),
-	MATCH(?SendPos, ?ParamPos, ?DontCarePos),
+	MATCH(?SendPos, ?ParamPos),
 	hasParam(?Method, ?ParamType, ?Param, ?ParamPos),
 	ASSIGN(?ParamType, ?SentValue, ?ReceivedValue),
 	GroupAs(?Method, ?TargetInvocation).

src/main/sam/system.sam

@@ -46,7 +46,7 @@ didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?Method) :-
 	hasMethod(?TargetType, ?Method),
 	callsMethod(?CallSite, ?MethodName1),
 	methodName(?Method, ?MethodName2),
-	MATCH(?MethodName1, ?MethodName2, ?MethodName),
+	MATCH(?MethodName1, ?MethodName2),
 	accessAllowed(?Caller, ?Target, ?Method).
 
 // For dynamic receivers
@@ -71,7 +71,7 @@ didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?Method) :-
 	callsMethodInLocal(?CallSite, ?LocalVarName),
 	local(?Caller, ?CallerInvocation, ?LocalVarName, ?MethodName1),
 	methodName(?Method, ?MethodName2),
-	MATCH(?MethodName1, ?MethodName2, ?MethodName),
+	MATCH(?MethodName1, ?MethodName2),
 	accessAllowed(?Caller, ?Target, ?Method).
 
 didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?CallerInvocation, ?Method) :-
@@ -146,7 +146,7 @@ maySend(?Caller, ?CallerInvocation, ?CallSite, ?Pos, ?ArgValue) :-
 didReceive(?Target, ?TargetInvocation, ?Method, ?ParamPos, ?ReceivedValue) :-
 	didCall(?Caller, ?CallerInvocation, ?CallSite, ?Target, ?TargetInvocation, ?Method),
 	maySend(?Caller, ?CallerInvocation, ?CallSite, ?SendPos, ?SentValue),
-        MATCH(?SendPos, ?ParamPos, ?DontCarePos),
+        MATCH(?SendPos, ?ParamPos),
         hasParam(?Method, ?ParamType, ?Param, ?ParamPos),
         ASSIGN(?ParamType, ?SentValue, ?ReceivedValue),
         !methodDoesContextMapping(?Method).
@@ -165,7 +165,7 @@ hasIdentity(?Child, ?Identity) :-
 accessAllowed(?Caller, ?Target, ?Method) :-
     hasIdentity(?Caller, ?CallerIdentity),              // Caller's identity is Identity
     grantsRole(?Target, ?Role, ?GrantedIdentity),       // Target grants Role to Identity
-    MATCH(?CallerIdentity, ?GrantedIdentity, ?UnusedResult),  // Might be any() type
+    MATCH(?CallerIdentity, ?GrantedIdentity),  		// Might be any() type
     PermittedRole(?Method, ?Role).                      // Role is allowed to invoke the method
 
 /* Objects may call others with the same identity. */

src/test/testMatch.sam

@@ -39,7 +39,7 @@ declare xfer(Ref a, Ref b, int pos).
 xfer(?A, ?B, ?Pos) :-
     sends(?A, ?PosA),
     accepts(?B, ?PosB),
-    MATCH(?PosA, ?PosB, ?Pos).
+    MATCH_TO(?PosA, ?PosB, ?Pos).
 
 declare foo(String c, Object x).
 declare bar(String c, Object y).
@@ -65,7 +65,7 @@ bar("e", <y>).
 foo("f", any(Ref)).
 bar("f", any(Object)).
 
-match(?C, ?Z) :- foo(?C, ?X), bar(?C, ?Y), MATCH(?X, ?Y, ?Z).
+match(?C, ?Z) :- foo(?C, ?X), bar(?C, ?Y), MATCH_TO(?X, ?Y, ?Z).
 
 assert match("a", any(boolean)).
 assert match("b", any(boolean)).