Outline:

1. Quiz 4
2. Scheme special form: let
3. Variable scope
   • examples: Scheme, Python, C, Bash
   • lexical vs. dynamic scoping
4. Wrap-up

What’s next

Upcoming events/assessments:

• Interpreter Parts 1–3 (linked list + talloc + tokenizer) cannot be resubmitted after Wednesday at 10pm

What you should do now:

• Read the assigned readings (see below)
• Finish Interpreter Part 3: Tokenizer if you haven’t already
• Work on resubmitting Interpreter Parts 1–3 with more complete functionality, style fixes, etc.
• Start Interpreter Part 4: Parser

Reading assignment (to be completed by the next class):

Scoping (from today):

• Static vs dynamic scoping
• Scope (Wikipedia) – read Intro and Definition sections

Scheme Environment Model (for next time):

• Scheme Environment Model of Evaluation