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beautiful-racket/beautiful-racket-demo/algebra-demo/main.rkt

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#lang br/quicklang
(require brag/support "grammar.rkt")
(provide top fun expr app)
(module+ reader
(provide read-syntax))
(define-lex-abbrev reserved-toks
(:or "fun" "(" ")" "=" "+" ","))
(define tokenize-1
(lexer
[whitespace (token lexeme #:skip? #t)]
[(from/stop-before "#" "\n") (token 'COMMENT #:skip? #t)]
[reserved-toks lexeme]
[(:+ alphabetic) (token 'ID (string->symbol lexeme))]
[(:+ (char-set "0123456789")) (token 'INT (string->number lexeme))]))
(define-macro top #'#%module-begin)
(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 app #'#%app)
(define (read-syntax src ip)
(define parse-tree (parse src (λ () (tokenize-1 ip))))
(strip-bindings
(with-syntax ([PT parse-tree])
#'(module algebra-mod algebra-demo
PT))))