This course is the shortest complete route from “I have never used Lispex” to “I can write and test a small decision rule.” It has four lessons. Each one continues from the previous lesson, ends with a small exercise, and tells you when you are ready to move on.
Before you begin
Use any modern browser for the Playground. Local installation is optional in the first lesson; when you do install, the page gives both npm and Native paths. Keep about 30–45 minutes for the whole course, or stop after any lesson.
The course uses one reading rule repeatedly:
(operation input-1 input-2 ...)Parentheses do not mean “mysterious Lisp punctuation.” They show a form. Most
forms call a procedure; a small named set such as define, if, and quote
controls evaluation.
The four steps
1. First Program
Run one complete expression in the Playground, save it as a .lspx file, and
learn how a diagnostic points back to the source.
2. Values, Names, and Procedures
Read literals, bind names with define and let, and create a reusable
procedure. This lesson turns nested parentheses into a predictable evaluation
order.
3. Data, Conditions, and Decisions
Preserve symbols and lists as data, choose with if and cond, and remember
that only #f is false. You will return a labelled decision instead of an
unexplained boolean.
4. First Decision Rule
Combine the earlier pieces into a refund-window rule. Test day 14, day 15, and an opened item so the boundary is visible rather than assumed.
Build the first decision rule →
Keep this map beside the course
Syntax at a Glance shows literals, calls, bindings, procedures, conditions, quoted data, aggregates, and higher-order procedures on one page. Use it when you recognize a shape but cannot remember its name. The map links into the full manual; it is not another lesson to finish.
After the course
Choose the path that matches your next question:
- Write more Lispex: continue with Source Text and Reader, then the language guides.
- Ship a local rule: read Choosing a Runtime Surface and Downloads.
- Make source visual and reversible: try Lispex Images.
- Authenticate and recheck a decision: enter the advanced Lispex Vouch overview.
You do not need to read the manual in page-number order after this course. Use the navigation numbers as orientation, then follow the question you actually have.