Add & update notes on new grammar.

3 files changed, 65 insertions, 0 deletions

diff --git a/notes/250210-cons.md b/notes/250210-cons.md
index 3146957..1ce97b9 100644
--- a/notes/250210-cons.md
+++ b/notes/250210-cons.md
@@ -178,3 +178,34 @@ multiple values!
 
 (The phrase "argument list" is probably going to stick around forever
 though, even if it's technically wrong in Zisp.)
+
+## Grammar switch-up!
+
+_2026 January_
+
+For [reasons](260106-grammar.html) I've decided to actually use the
+ampersand in place of the dot in Zisp s-expressions.  Not like in the
+paper linked above; the ampersand simply replaces the dot in the
+representation of improper lists.
+
+Here's how some snippets from above would look with the new grammar:
+
+```scheme
+
+(define (map* proc & args)
+  (map proc (list & args)))
+
+(define combine*
+  (case-lambda
+    ((x) x)
+    ((x y & rest) (combine* (combine x y) & rest))))
+
+(define (foobar & rest)
+  (let-values (((x y z) rest))
+    ;; This is a meaningless example for demonstration, since we
+    ;; could have just made the function accept three parameters.
+    ;; The `let-values` here is the one from SRFI 11.
+    ))
+
+(apply display-if-found (lookup '((x & y)) 'x))  ;; displays x
+```
diff --git a/notes/260106-simpler-grammar.md b/notes/260106-simpler-grammar.md
new file mode 100644
index 0000000..ddfe619
--- /dev/null
+++ b/notes/260106-simpler-grammar.md
@@ -0,0 +1,33 @@
+# Simplifying S-Expression Grammar
+
+Supporting dots as part of identifiers and number literals, especially
+at the beginning like in `...` or `.5`, but then special-casing a lone
+dot for improper list syntax, is a bit annoying.
+
+It makes my otherwise crystal clear and simple BNF grammar, as well as
+my parser implementation, a bit less simple, which is bothersome.
+
+Since I've already broken off heavily from traditional s-expressions,
+I've decided to retire the dot as the improper list marker.  Instead
+I'll be using the ampersand.
+
+```
+;; The good old
+(foo bar . baz)
+
+;; The new kid
+(foo bar & baz)
+```
+
+This is way more annoying to type, and I've not yet gotten used to the
+way it looks.  But you don't type improper lists frequently in code,
+and I think the looks are just a matter of familiarity.
+
+By the way, the ampersand is now illegal in identifiers.  It's totally
+reserved for this singular purpose in the grammar.
+
+The only common use I know of is exception types in R6RS, which I've
+never liked anyway.  Using the question or exclamation marks would be
+more intuitive, to express a questionable situation or a surprise!
+
+I might walk back on this eventually, but so far it seems OK.
diff --git a/notes/index.md b/notes/index.md
index 63ef532..dd5a946 100644
--- a/notes/index.md
+++ b/notes/index.md
@@ -22,3 +22,4 @@
 * [Using libgccjit?](250920-libgccjit.html)
 * [Goals](250920-goals.html)
 * [A full-stack programming language](260102-full-stack.html)
+* [Simplifying S-Expression Grammar](260106-simpler-grammar.html)