CS: add step3_env

Also, make Makefile more closely match the C Makefile.

1 files changed, 55 insertions, 0 deletions

diff --git a/cs/env.cs b/cs/env.cs
new file mode 100644
index 0000000..cb5318f
--- /dev/null
+++ b/cs/env.cs
@@ -0,0 +1,55 @@
+using System.Collections.Generic;
+using Mal;
+using MalVal = Mal.types.MalVal;
+using MalSymbol = Mal.types.MalSymbol;
+using MalList = Mal.types.MalList;
+
+namespace Mal {
+    public class env {
+        public class Env {
+            Env outer = null;
+            Dictionary<string, MalVal> data = new Dictionary<string, MalVal>();
+
+            public Env(Env outer) {
+                this.outer = outer;
+            }
+            public Env(Env outer, MalList binds, MalList exprs) {
+                this.outer = outer;
+                for (int i=0; i<binds.size(); i++) {
+                    string sym = ((MalSymbol)binds.nth(i)).getName();
+                    if (sym == "&") {
+                        data[((MalSymbol)binds.nth(i+1)).getName()] = exprs.slice(i);
+                        break;
+                    } else {
+                        data[sym] = exprs.nth(i);
+                    }
+                }
+            }
+            
+            public Env find(string key) {
+                if (data.ContainsKey(key)) {
+                    return this;
+                } else if (outer != null) {
+                    return outer.find(key);
+                } else {
+                    return null;
+                }
+            }
+
+            public MalVal get(string key) {
+                Env e = find(key);
+                if (e == null) {
+                    throw new Mal.types.MalException(
+                            "'" + key + "' not found");
+                } else {
+                    return e.data[key];
+                }
+            }
+
+            public Env set(string key, MalVal value) {
+                data[key] = value;
+                return this;
+            }
+        }
+    }
+}