an API for inspecting expressions in Java

2 files changed, 25 insertions, 0 deletions

diff --git a/src/runtime/java/org/grammaticalframework/pgf/Expr.java b/src/runtime/java/org/grammaticalframework/pgf/Expr.java
index 2c6882203..cdc62d1d1 100644
--- a/src/runtime/java/org/grammaticalframework/pgf/Expr.java
+++ b/src/runtime/java/org/grammaticalframework/pgf/Expr.java
@@ -83,6 +83,12 @@ public class Expr implements Serializable {
 			return new Expr(pool, master, initApp(fun, args, pool.ref));
 		}
 
+		/** If the method is called on an expression which is 
+		 * a function application, then it is decomposed into 
+		 * a function name and a list of arguments. If this is not 
+		 * an application then the result is null. */
+		public native ExprApplication unApply();
+
 		/** Returns the expression as a string in the GF syntax */
 		public String toString() {
 			return showExpr(ref);
diff --git a/src/runtime/java/org/grammaticalframework/pgf/ExprApplication.java b/src/runtime/java/org/grammaticalframework/pgf/ExprApplication.java
new file mode 100644
index 000000000..d33269448
--- /dev/null
+++ b/src/runtime/java/org/grammaticalframework/pgf/ExprApplication.java
@@ -0,0 +1,19 @@
+package org.grammaticalframework.pgf;
+
+public class ExprApplication {
+	private String fun;
+	private Expr[] arguments;
+
+	public ExprApplication(String fun, Expr[] arguments) {
+		this.fun       = fun;
+		this.arguments = arguments;
+	}
+	
+	public String getFunction() {
+		return fun;
+	}
+	
+	public Expr[] getArguments() {
+		return arguments;
+	}
+}