diff --git a/beautiful-racket-demo/algebra-demo/grammar.rkt b/beautiful-racket-demo/algebra-demo/grammar.rkt
index 7ff8428..7668cee 100644
--- a/beautiful-racket-demo/algebra-demo/grammar.rkt
+++ b/beautiful-racket-demo/algebra-demo/grammar.rkt
@@ -1,9 +1,6 @@
 #lang brag
 
-top : (func-def | func-app)*
-func-def : /"fun" var /"(" vars /")" /"=" expr
-/vars : var [/"," var]
-expr : var "+" var | value
-@value : var | INT | func-app
-func-app : var /"(" value [/"," value] /")"
-@var : ID
+top : (fun | app)*
+fun : /"fun" ID /"(" ID [/"," ID] /")" /"=" expr
+expr : ID "+" ID | app
+app : ID /"(" (ID | INT) [/"," ID] /")"
\ No newline at end of file
diff --git a/beautiful-racket-demo/algebra-demo/main.rkt b/beautiful-racket-demo/algebra-demo/main.rkt
index 9f1b4b8..1b401d9 100644
--- a/beautiful-racket-demo/algebra-demo/main.rkt
+++ b/beautiful-racket-demo/algebra-demo/main.rkt
@@ -1,6 +1,6 @@
 #lang br/quicklang
 (require brag/support "grammar.rkt")
-(provide (all-defined-out) #%module-begin)
+(provide top fun expr app)
 
 (module+ reader
   (provide read-syntax))
@@ -8,27 +8,29 @@
 (define-lex-abbrev reserved-toks
   (:or "fun" "(" ")" "=" "+" ","))
 
-(define tokenize
+(define tokenize-1
   (lexer
-   [whitespace (tokenize input-port)]
+   [whitespace (token lexeme #:skip? #t)]
+   [(from/stop-before "%" "\n") (token 'COMMENT #:skip? #t)]
    [reserved-toks lexeme]
-   [alphabetic (token 'ID (string->symbol lexeme))]
+   [(:+ alphabetic) (token 'ID (string->symbol lexeme))]
    [(:+ (char-set "0123456789")) (token 'INT (string->number lexeme))]))
 
-(define-macro top #'begin)
+(define-macro top #'#%module-begin)
 
-(define-macro (func-def VAR VARS EXPR)
-  #'(define (VAR . VARS) EXPR))
+(define-macro-cases fun
+  [(_ VAR ARG0 EXPR) #'(define (VAR ARG0) EXPR)]
+  [(_ VAR ARG0 ARG1 EXPR) #'(define (VAR ARG0 ARG1) EXPR)])
 
 (define-macro-cases expr
   [(_ LEFT "+" RIGHT) #'(+ LEFT RIGHT)]
   [(_ OTHER) #'OTHER])
 
-(define-macro func-app #'#%app)
+(define-macro app #'#%app)
 
 (define (read-syntax src ip)
-  (define parse-tree (parse (λ () (tokenize ip))))
-  (strip-context
+  (define parse-tree (parse src (λ () (tokenize-1 ip))))
+  (strip-bindings
    (with-syntax ([PT parse-tree])
-     #'(module mod-name algebra-demo
+     #'(module algebra-mod algebra-demo
          PT))))
\ No newline at end of file
diff --git a/beautiful-racket-demo/algebra-demo/test.rkt b/beautiful-racket-demo/algebra-demo/test.rkt
index 093dd56..4ac4204 100644
--- a/beautiful-racket-demo/algebra-demo/test.rkt
+++ b/beautiful-racket-demo/algebra-demo/test.rkt
@@ -1,4 +1,6 @@
 #lang algebra-demo
-fun f(x,y) = x + y 
-fun g(z) = f(z,z)
-g(10)
\ No newline at end of file
+fun f(x,y) = x + y
+% fun f(x,y) = x * y
+fun g(zz) = f(zz,zz)
+g(10)
+g(23)
\ No newline at end of file