initial commit of most and last

1 files changed, 28 insertions, 0 deletions

diff --git a/chunk.d b/chunk.d
index 55772dc..21ebb9d 100644
--- a/chunk.d
+++ b/chunk.d
@@ -45,6 +45,8 @@ abstract class Seq {
     SeqType type;
     abstract Value first();
     abstract Seq rest();
+    abstract Seq most();
+    abstract Value last();
     abstract int length();
     abstract bool isIn(Value val);
 }
@@ -70,6 +72,14 @@ class String : Seq {
         return new String(this.str[1..$]);
     }
 
+    override Seq most() {
+        return new String(this.str[0..$ - 1]);
+    }
+
+    override Value last() {
+        return makeStringValue(to!string(this.str[$ - 1]));
+    }
+
     override int length() {
         return to!int(str.length);
     }
@@ -133,6 +143,22 @@ class List : Seq {
         return ret;
     }
 
+    override Seq most() {
+        if (this.inner.length == 0) {
+            return new List(0);
+        }
+        int newLength = to!int(this.inner.length) - 1;
+        List ret = new List(newLength);
+        for (int i = 0; i < newLength; i++) {
+            ret.addItemAtIndex(this.inner[i], i);
+        }
+        return ret;
+    }
+
+    override Value last() {
+        return this.inner[$ - 1];  // this fails on NIL
+    }
+
     override int length() {
         return to!int(this.inner.length);
     }
@@ -195,7 +221,9 @@ enum OpCode {
     OP_APPEND,
     OP_FIRST,   // No?
     OP_LENGTH,
+    OP_LAST,
     OP_MEMBER,
+    OP_MOST,
     OP_REST,
 
     // DEFINITIONS/VARIABLES