From 788124a96cebcc72decb2007995906964bbaea08 Mon Sep 17 00:00:00 2001
From: krasimir <krasimir@chalmers.se>
Date: Wed, 10 May 2017 14:41:55 +0000
Subject: [PATCH] added Expr.apply

---
 src/runtime/java/jpgf.c                       | 26 ++++++++++++++++++-
 .../org/grammaticalframework/pgf/Expr.java    | 24 ++++++++++++++++-
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/src/runtime/java/jpgf.c b/src/runtime/java/jpgf.c
index 560f0e317..026bd9a48 100644
--- a/src/runtime/java/jpgf.c
+++ b/src/runtime/java/jpgf.c
@@ -1226,8 +1226,32 @@ Java_org_grammaticalframework_pgf_Expr_initStringLit(JNIEnv* env, jclass clazz,
 	return expr;
 }
 
+JNIEXPORT jlong JNICALL
+Java_org_grammaticalframework_pgf_Expr_initApp__Lorg_grammaticalframework_pgf_Expr_2_3Lorg_grammaticalframework_pgf_Expr_2J
+(JNIEnv* env, jclass clazz, jobject jfun, jobjectArray args, jlong jpool)
+{
+	GuPool* pool = l2p(jpool);
+	PgfExpr expr = gu_variant_from_ptr(get_ref(env, jfun));
+
+	size_t n_args = (*env)->GetArrayLength(env, args);
+	for (size_t i = 0; i < n_args; i++) {
+		PgfExpr fun = expr;
+		PgfExpr arg = gu_variant_from_ptr(get_ref(env, (*env)->GetObjectArrayElement(env, args, i)));
+
+		PgfExprApp* e =
+			gu_new_variant(PGF_EXPR_APP,
+						   PgfExprApp,
+						   &expr, pool);
+		e->fun = fun;
+		e->arg = arg;
+	}
+
+	return expr;
+}
+
 JNIEXPORT jlong JNICALL 
-Java_org_grammaticalframework_pgf_Expr_initApp(JNIEnv* env, jclass clazz, jstring jfun, jobjectArray args, jlong jpool)
+Java_org_grammaticalframework_pgf_Expr_initApp__Ljava_lang_String_2_3Lorg_grammaticalframework_pgf_Expr_2J
+(JNIEnv* env, jclass clazz, jstring jfun, jobjectArray args, jlong jpool)
 {
 	GuPool* pool = l2p(jpool);
 	PgfExpr expr;
diff --git a/src/runtime/java/org/grammaticalframework/pgf/Expr.java b/src/runtime/java/org/grammaticalframework/pgf/Expr.java
index 0195f8019..6541db140 100644
--- a/src/runtime/java/org/grammaticalframework/pgf/Expr.java
+++ b/src/runtime/java/org/grammaticalframework/pgf/Expr.java
@@ -44,10 +44,31 @@ public class Expr implements Serializable {
 			}
 
 			this.pool   = new Pool();
-			this.master = Arrays.copyOf(args, args.length);
+			this.master = args;
 			this.ref    = initApp(fun, args, pool.ref);
 		}
 
+		/** Constructs an expression which is an application
+		 * of the first expression to a list of arguments.
+		 */
+		public static Expr apply(Expr fun, Expr... args) {
+			if (fun == null)
+				throw new IllegalArgumentException("fun == null");
+			for (int i = 0; i < args.length; i++) {
+				if (args[i] == null)
+					throw new IllegalArgumentException("the "+(i+1)+"th argument is null");
+			}
+
+			Object[] master = new Object[args.length+1];
+			master[0] = fun;
+			for (int i = 0; i < args.length; i++) {
+				master[i+1] = args[i].master;
+			}
+
+            Pool pool = new Pool();
+			return new Expr(pool, master, initApp(fun, args, pool.ref));
+		}
+
 		/** Returns the expression as a string in the GF syntax */
 		public String toString() {
 			return showExpr(ref);
@@ -64,6 +85,7 @@ public class Expr implements Serializable {
 		private static native String showExpr(long ref);
 
 		private static native long initStringLit(String s, long pool);
+		private static native long initApp(Expr   fun, Expr[] args, long pool);
 		private static native long initApp(String fun, Expr[] args, long pool);
 
 		private void writeObject(ObjectOutputStream out) throws IOException {