added shell tab complete

ast/func_table.go

@@ -75,3 +75,18 @@ func GetFunction(arg string, table FuncTable) *Function {
 
     return target
 }
+
+
+/* lists all functions in table
+ */
+func ListFuncs(ft FuncTable) []string {
+    keys := make([]string, len(*ft))
+    i := 0
+
+    for k := range *ft {
+        keys[i] = k
+        i++
+    }
+
+    return keys
+}