precalc

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

@@ -1,9 +1,9 @@
 #lang brag
 
 top : (func-def | func-app)*
-func-def : /"fun" var /"(" boundvars /")" /"=" expr
+func-def : /"fun" var /"(" vars /")" /"=" expr
-/boundvars : var [/"," var]
+/vars : var [/"," var]
-expr : var "+" var | func-app
+expr : var "+" var | value
-func-app : var /"(" arg [/"," arg] /")"
+@value : var | INT | func-app
+func-app : var /"(" value [/"," value] /")"
 @var : ID
-@arg : var | INT

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

@@ -17,15 +17,14 @@
 
 (define-macro top #'begin)
 
-(define-macro (func-def ID ARGIDS EXPR)
+(define-macro (func-def VAR VARS EXPR)
-  #'(define ID (λ ARGIDS EXPR)))
+  #'(define VAR (λ VARS EXPR)))
 
 (define-macro-cases expr
   [(_ LEFT "+" RIGHT) #'(+ LEFT RIGHT)]
   [(_ OTHER) #'OTHER])
 
-(define-macro (func-app ID ARG ...)
+(define-macro func-app #'#%app)
-  #'(ID ARG ...))
 
 (define (read-syntax src ip)
   (define token-thunk (λ () (lex ip)))

beautiful-racket-demo/precalc-demo/grammar.rkt

@@ -0,0 +1,11 @@
+#lang brag
+
+top : (func-def | expr)*
+func-def : /"fun" var /"(" vars /")" /"=" expr
+/vars : [var [/"," var]*]
+@expr : sum
+sum : [sum ("+" | "-")] product
+product : [product ("*" | "/")] value
+@value : var | INT | func-app | /"(" expr /")"
+func-app : var /"(" [value [/"," value]*] /")"
+@var : ID

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

@@ -0,0 +1,43 @@
+#lang br/quicklang
+(require brag/support "grammar.rkt")
+(provide (all-defined-out) #%module-begin)
+
+(module+ reader
+  (provide read-syntax))
+
+(define-lex-abbrev reserved-toks
+  (:or "fun" "(" ")" "=" "+" "*" "/" "-" ","))
+
+(define lex
+  (lexer
+   [(:or (from/to "//" "\n") (from/to "/*" "*/")) (token 'COMMENT #:skip? #t)]
+   [whitespace (lex input-port)]
+   [reserved-toks lexeme]
+   [alphabetic (token 'ID (string->symbol lexeme))]
+   [(:+ (char-set "0123456789")) (token 'INT (string->number lexeme))]))
+
+(define-macro top #'begin)
+
+(define-macro (func-def ID ARGIDS EXPR)
+  #'(define ID (λ ARGIDS EXPR)))
+
+(define-macro-cases sum
+  [(_ LEFT "+" RIGHT) #'(+ LEFT RIGHT)]
+  [(_ LEFT "-" RIGHT) #'(- LEFT RIGHT)]
+  [(_ OTHER) #'OTHER])
+
+(define-macro-cases product
+  [(_ LEFT OP-STR RIGHT)
+   (with-syntax ([OP (string->symbol (syntax->datum #'OP-STR))])
+     #'(OP LEFT RIGHT))]
+  [(_ OTHER) #'OTHER])
+
+(define-macro func-app #'#%app)
+
+(define (read-syntax src ip)
+  (define token-thunk (λ () (lex ip)))
+  (define parse-tree (parse token-thunk))
+  (strip-context
+   (with-syntax ([PT parse-tree])
+     #'(module mod-name precalc-demo
+         PT))))

beautiful-racket-demo/precalc-demo/test.rkt

@@ -0,0 +1,18 @@
+#lang precalc-demo
+fun f(x, y, z) = x + x + x * (y + y) + y * z - z - z
+
+fun g(z) = f(z, z, z) // line comment
+g(10) // 300
+
+fun h() = g(10)
+h() // also 300
+
+fun k(x) = x / 10 / 10 / (x / x)
+k(h()) // 3
+
+36/6/2 // 3
+
+/*
+multiline comment
+0 / 0 / 0
+*/