1 files changed, 21 insertions, 0 deletions
diff --git a/src/sexp/step.rs b/src/sexp/step.rs
index 9077401..59b201c 100644
--- a/src/sexp/step.rs
+++ b/src/sexp/step.rs
@@ -441,6 +441,27 @@ impl SExp {
 	    },
 
 
+	    // Concatenation
+	    SCons(op, l) if *op == Atom(Concat) => {
+		let ls = l.parts();
+		let firstvec = ls.get(0).unwrap();
+		let secondvec = ls.get(1).unwrap();
+		let firstvec = match firstvec {
+		    SCons(a, b) if **a == Atom(Vector) => *b.clone(),
+		    t => t.clone(),
+		};
+		let secondvec = match secondvec {
+		    SCons(a, b) if **a == Atom(Vector) => *b.clone(),
+		    t => t.clone(),
+		};
+		let mut res = Atom(Nil);
+		for exp in firstvec.parts().into_iter().chain(secondvec.parts()).rev() {
+		    res = scons(exp, res);
+		}
+		Ok(scons(Vector, res))
+	    },
+
+
             // Arithmetic