let true = (\x (\y x)) in
let false = (\x (\y y)) in
- ((true true) false)
+ ((true yes) no)
-the result is `true`.
+the result is `yes`. Things to watch out for: the expression after the equal sign must have balanced parentheses,
+and the "in" is obligatory. The system will still produce a result, but it won't make much sense.
+
+*Abbreviations*, **NOT**: No abbreviations work. So `\xy.yxx` must be written `(\x (\y ((y x) x)))`. (As in Scheme or Racket.)
+
+*Comments*: anything following a semicolon to the end of the line is ignored.
+Blank lines are fine.
+
+Under the hood
+---------------
+
+The interpreter is written in JavaScript (which is not closely related to Java), and runs inside your browser.
+So if you decide to reduce a term that does not terminate (such as `((\x (x x)) (\x (x x)))`), it will be your
+browser that stops responding, not the wiki server.
+
+You can inspect the code [here](http://lambda.jimpryor.net/code/lambda.js). Suggestions for improvements welcome.
+
+Improvements we hope to add soon: the ability to reduce Combinatory Logic combinators; the ability to translate from CL to the lambda calculus; and more sensible variable names instead of `g354`.
-*Comments*:
-[more soon]