fix mod

beautiful-racket-demo/basic-demo-2/expr.rkt

@@ -12,8 +12,12 @@
   [(_ VAL) #'VAL]
   [(_ LEFT "*" RIGHT) #'(* LEFT RIGHT)]
   [(_ LEFT "/" RIGHT) #'(/ LEFT RIGHT 1.0)]
-  [(_ LEFT "^" RIGHT) #'(expt LEFT RIGHT)]
-  [(_ LEFT "%" RIGHT) #'(modulo LEFT RIGHT)])
+  [(_ LEFT "mod" RIGHT) #'(modulo LEFT RIGHT)])
+
+;; b-expt : [b-expt "^"] b-value
+(define-macro-cases b-expt
+  [(_ VAL) #'VAL]
+  [(_ LEFT "^" RIGHT) #'(expt LEFT RIGHT)])
 
 (define (b-expr expr)
   (if (integer? expr) (inexact->exact expr) expr))

beautiful-racket-demo/basic-demo-2/lexer.rkt

@@ -3,7 +3,7 @@
 
 (define-lex-abbrev digits (:+ (char-set "0123456789")))
 
-(define-lex-abbrev reserved-terms (:or "print" "goto" "end" "+" ":" "let" "=" "gosub" "return" "-" "for" "to" "step" "next" "if" "then" "else" "and" "or" "<" ">" "*" "/" "(" ")" "^" "!" "%" "input" ";" "def"))
+(define-lex-abbrev reserved-terms (:or "print" "goto" "end" "+" ":" "let" "=" "gosub" "return" "-" "for" "to" "step" "next" "if" "then" "else" "and" "or" "<" ">" "*" "/" "(" ")" "^" "!" "mod" "input" ";" "def"))
 
 (define basic-lexer
   (lexer-srcloc

beautiful-racket-demo/basic-demo-2/parser.rkt

@@ -25,7 +25,8 @@ b-expr : b-logic-expr
 b-logic-expr : [b-logic-expr ("and" | "or")] b-comp-expr
 b-comp-expr : [b-comp-expr ("=" | "<" | ">")] b-sum
 b-sum : [b-sum ("+"|"-")] b-product
-b-product : [b-product ("*"|"/"|"%"|"^")] b-value
+b-product : [b-product ("*"|"/"|"mod")] b-expt
+b-expt : [b-expt "^"] b-value
 
 ;; values
 @b-value : b-id | b-number | /"(" b-expr /")" | b-not | b-func