X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=week1.mdwn;h=b4d584d4f7db1676ab42891b9e32f3d5980599f6;hp=5ae3e65f5c154f36a84432585178ed81bdb179ba;hb=1a4c40836dc37109b086d47ee9fb27c2f9726e6b;hpb=9452f39dcc5b7babde45142e2b24e3617813d6a6

diff --git a/week1.mdwn b/week1.mdwn
index 5ae3e65f..b4d584d4 100644
--- a/week1.mdwn
+++ b/week1.mdwn
@@ -39,6 +39,24 @@ Basics of Lambda Calculus
 
 The lambda calculus we'll be focusing on for the first part of the course has no types. (Some prefer to say it instead has a single type---but if you say that, you have to say that functions from this type to this type also belong to this type. Which is weird.)
 
+Here is its syntax:
+
+<blockquote>
+<strong>Variables</strong>: <code>x</code>, <code>y</code>, <code>z</code>...
+</blockquote>
+
+Each variable is an expression. For any expressions M and N and variable a, the following are also expressions:
+
+<blockquote>
+<strong>Abstract</strong>: <code>(&lambda;a M)</code>
+</blockquote>
+
+We'll tend to write <code>(&lambda;a M)</code> as just `(\a M)`, so we don't have to write out the markup code for the <code>&lambda;</code>. You can yourself write <code>(&lambda;a M)</code> or `(\a M)` or `(lambda a M)`.
+
+<blockquote>
+<strong>Application</strong>: <code>(M N)</code>
+</blockquote>
+
 Some authors reserve the term "term" for just variables and abstracts. We'll probably just say "term" and "expression" indiscriminately for expressions of any of these three forms.
 
 Examples of expressions:
@@ -585,7 +603,6 @@ Here's how it looks to say the same thing in various of these languages.
 
 	It's easy to be lulled into thinking this is a kind of imperative construction. *But it's not!* It's really just a shorthand for the compound "let"-expressions we've already been looking at, taking the maximum syntactically permissible scope. (Compare the "dot" convention in the lambda calculus, discussed above.)
 
-
 9.	Some shorthand
 
 	OCaml permits you to abbreviate:
@@ -656,9 +673,11 @@ Here's how it looks to say the same thing in various of these languages.
 
 	and there's no more mutation going on there than there is in:
 
+	<!--
 	<pre>
 	<code>&forall;x. (F x or &forall;x (not (F x)))</code>
 	</pre>
+	-->
 
 	When a previously-bound variable is rebound in the way we see here, that's called **shadowing**: the outer binding is shadowed during the scope of the inner binding.