Class Lambda

src/main/java/wyil/lang/WyilFile.java:1185–1251

Represents a lambda declaration within a Whiley source file. Sometimes also known as closures, these are anonymous function or method declarations declared within an expression. The following illustrates: type func is function(int)->int function g() -> func: return &(int x -> x +

		 *
		 */
		public static class Lambda extends Callable implements Expr {

			public Lambda(Tuple<Modifier> modifiers, Identifier name, Tuple<Decl.Variable> parameters, Expr body,
					WyilFile.Type.Callable signature) {
				this(modifiers, name, new Tuple<>(), parameters, new Tuple<Decl.Variable>(), body, signature);
			}


			public Lambda(Tuple<Modifier> modifiers, Identifier name, Tuple<Template.Variable> template,
					Tuple<Decl.Variable> parameters, Tuple<Decl.Variable> returns, Expr body, WyilFile.Type.Callable signature) {
				super(DECL_lambda, modifiers, name, template, parameters, returns, body, signature);
			}

			public Set<Decl.Variable> getCapturedVariables() {
				UsedVariableExtractor usedVariableExtractor = new UsedVariableExtractor();
				HashSet<Decl.Variable> captured = new HashSet<>();
				usedVariableExtractor.visitExpression(getBody(), captured);
				Tuple<Decl.Variable> parameters = getParameters();
				for (int i = 0; i != parameters.size(); ++i) {
					captured.remove(parameters.get(i));
				}
				return captured;
			}

			@Override
			public Expr getBody() {
				return (Expr) get(5);
			}

			@Override
			public WyilFile.Type.Callable getType() {
				return (WyilFile.Type.Callable) super.get(6);
			}

			@Override
			public void setType(WyilFile.Type type) {
				// FIXME: this is a hack which should be removed.
				type = type.as(WyilFile.Type.Callable.class);
				Syntactic.Heap heap = getHeap();
				//
				if (type instanceof WyilFile.Type.Callable) {
					// Set the type
					operands[6] = heap.allocate(type);
				} else {
					throw new IllegalArgumentException();
				}
			}

			@SuppressWarnings("unchecked")
			@Override
			public Syntactic.Item clone(Syntactic.Item[] operands) {
				return new Lambda((Tuple<Modifier>) operands[0], (Identifier) operands[1],
						(Tuple<Template.Variable>) operands[2], (Tuple<Decl.Variable>) operands[3],
						(Tuple<Decl.Variable>) operands[4], (Expr) operands[5], (WyilFile.Type.Callable) operands[6]);
			}

			public static final Descriptor DESCRIPTOR_0 = new Descriptor(Operands.SEVEN, Data.ZERO, "DECL_lambda") {
				@SuppressWarnings("unchecked")