1 files changed, 25 insertions, 0 deletions
diff --git a/nim/env.nim b/nim/env.nim
new file mode 100644
index 0000000..7432d09
--- /dev/null
+++ b/nim/env.nim
@@ -0,0 +1,25 @@
+import tables, types
+
+proc initEnv*(outer: Env = nil, binds, exprs: MalType = nilObj): Env =
+  result = Env(data: initTable[string, MalType](), outer: outer)
+
+  if binds.kind in {List, Vector}:
+    for i, e in binds.list:
+      if e.str == "&":
+        result.data[binds.list[i+1].str] = list(exprs.list[i .. -1])
+        break
+      else:
+        result.data[e.str] = exprs.list[i]
+
+proc set*(e: var Env, key: string, value: MalType): MalType {.discardable.} =
+  e.data[key] = value
+  value
+
+proc find*(e: Env, key: string): Env =
+  if e.data.hasKey(key): return e
+  if e.outer != nil:     return e.outer.find(key)
+
+proc get*(e: Env, key: string): MalType =
+  let env = e.find(key)
+  if env == nil: raise newException(ValueError, "'" & key & "' not found")
+  env.data[key]