add list functions to stdlib

stdlib/Readme.md

@@ -13,7 +13,7 @@ type Function struct {
     function    Operation
     name        string
     timesCalled int
-    args        int // TODO: Make this a list of expected types (TAGs)
+    args        int
 }
 
 type FuncTable map[string]*Function
@@ -31,6 +31,12 @@ The standard library is loaded during the init step of the repl (or interpreter
 2. *Create a `Function` to encapsulate your `Operation`.* Make sure to set the `args` and `name` fields. Args will be used to validate function calls and Name will be used in debug/log output.
 3. *Add your `Function` to the `FuncTable`.* Make sure your `Operations`s get added to the table generated in `GenFuncTable`.
 
+## Tips
+- You can use the Log module to add helpful output to your functions.
+- Try not to clutter the output with unnessesary ERR level logging.
+- Make sure you properly set the Next element of any Token you swap into a list
+- Make sure you properly set the Next element of the previous Token as you swap a token into a list
+
 ## License
 Copyright (C) 2019 Aidan Hahn.