1 files changed, 26 insertions, 0 deletions

diff --git a/chunk.d b/chunk.d
index 08ba003..7a532f5 100644
--- a/chunk.d
+++ b/chunk.d
@@ -46,6 +46,7 @@ abstract class Seq {
     abstract Value first();
     abstract Seq rest();
     abstract int length();
+    abstract Seq concat(Seq seq);
 }
 
 class String : Seq {
@@ -53,10 +54,12 @@ class String : Seq {
 
     this(Value value) {
         this.str = value.as.str;
+        this.type = SeqType.STRING;
     }
 
     this(string str) {
         this.str = str;
+        this.type = SeqType.STRING;
     }
 
     override Value first() {
@@ -71,6 +74,19 @@ class String : Seq {
         return to!int(str.length);
     }
 
+    override Seq concat(Seq seq) {
+        if (seq.type != SeqType.STRING) {
+            // how do i throw an error here?
+            writeln("must concat strings to strings!");
+            return this;
+        }
+        String strSeq = cast(String)seq;
+
+        writefln("in concat with '%s' and '%s'", this.str, strSeq.str);
+
+        return new String(this.str ~ strSeq.str);
+    }
+
     override string toString() {
         return format("\"%s\"", this.str);
     }
@@ -104,6 +120,16 @@ class List : Seq {
         return to!int(this.inner.length);
     }
 
+    override Seq concat(Seq seq) {
+        int length = to!int(this.inner.length);
+        List ret = new List(length + 1);
+        for (int i = 0; i < length; i++) {
+            ret.addItemAtIndex(this.inner[i], i);
+        }
+        ret.addItemAtIndex(makeSeqValue(seq), length);
+        return ret;
+    }
+
     override string toString() {
         return format("list ('%s' + %d)", printableValue(this.inner[0]), this.inner.length - 1);
     }