updates

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

@@ -3,8 +3,7 @@
 
 (define-lex-abbrev digits (:+ (char-set "0123456789")))
 
-(define (handle-tok-error tok-ok? tok-name tok-value start-pos end-pos)
-  (token 'ERROR tok-value))
+(define-lex-abbrev reserved-terms (:or "print" "goto" "end" "+" ":" "let" "=" "gosub" "return" "-" "for" "to" "step" "next" "if" "then" "else" "and" "or" "<" ">" "*" "/" "(" ")" "^" "!" "%" "input" ";" "def"))
 
 (define basic-lexer
   (lexer-srcloc
@@ -12,9 +11,9 @@
    ["\n" (token 'NEWLINE lexeme)]
    [whitespace (token lexeme #:skip? #t)]
    [(from/stop-before "rem" "\n") (token 'REM lexeme)]
-   [(:or "print" "goto" "end" "+" ":" "gosub" "return" "let" "=" "-" "for" "to" "step" "next"
-         "if" "then" "else" "and" "or" "<" ">" "*" "/" "(" ")" "^" "!" "%" "input" ";" "def") (token lexeme lexeme)]
-   [(:seq (:+ alphabetic) (:* (:or alphabetic numeric "$"))) (token 'ID (string->symbol lexeme))]
+   [reserved-terms (token lexeme lexeme)]
+   [(:seq alphabetic (:* (:or alphabetic numeric "$")))
+    (token 'ID (string->symbol lexeme))]
    [digits (token 'INTEGER (string->number lexeme))]
    [(:or (:seq (:? digits) "." digits)
          (:seq digits "."))

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

@@ -1,22 +1,22 @@
 #lang brag
 ;; program & lines
 b-program : [b-line] (/NEWLINE [b-line])*
-b-line : b-line-number [b-statement] (/":" [b-statement])* [b-rem]
-@b-line-number : INTEGER
+b-line : b-line-num [b-statement] (/":" [b-statement])* [b-rem]
+@b-line-num : INTEGER
 b-rem : REM
-
-;; statements
-@b-statement : b-end | b-print | b-let | b-input | b-def
-             | b-goto | b-gosub | b-return | b-for | b-next | b-if
+@b-statement :  b-rem | b-end | b-print | b-goto  | b-let
+| b-input | b-def | b-gosub
+| b-return | b-for | b-next | b-if
 b-end : /"end"
-b-print : /"print" [STRING | b-expr] (/";" [STRING | b-expr])*
+b-print : /"print" [b-printable] (/";" [b-printable])*
+@b-printable : STRING | b-expr
 b-goto : /"goto" b-expr
+b-let : [/"let"] b-id /"=" (STRING | b-expr)
 b-if : /"if" b-expr /"then" b-expr [/"else" b-expr]
 b-gosub : /"gosub" b-expr
 b-return : /"return"
 b-input : /"input" b-id
 b-def :  /"def" b-id /"(" b-id /")" /"=" b-expr
-b-let : [/"let"] b-id /"=" [STRING | b-expr]
 b-for : /"for" b-id /"=" b-expr /"to" b-expr [/"step" b-expr]
 b-next : /"next" [b-id]
 

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

@@ -1,7 +1,7 @@
 #lang brag
 b-program : [b-line] (/NEWLINE [b-line])*
-b-line : b-line-number [b-statement] (/":" [b-statement])*
-@b-line-number : INTEGER
+b-line : b-line-num [b-statement] (/":" [b-statement])*
+@b-line-num : INTEGER
 @b-statement : b-rem | b-end | b-print | b-goto
 b-rem : REM
 b-end : /"end"

beautiful-racket-demo/basic-demo-3/parser.rkt

@@ -1,8 +1,8 @@
 #lang brag
 ;; program & lines
 b-program : [b-line] (/NEWLINE [b-line])*
-b-line : b-line-number [b-statement] (/":" [b-statement])*
-@b-line-number : INTEGER
+b-line : b-line-num [b-statement] (/":" [b-statement])*
+@b-line-num : INTEGER
 
 ;; statements
 @b-statement : b-rem | b-end | b-print | b-let | b-input | b-def