add define-syntax-parser

idea from
863d39229f (diff-3252674930bbd0c4e113856a2a3a5747R118)

pkgs/racket-doc/syntax/scribblings/parse/define.scrbl

@@ -37,3 +37,25 @@ Defines a macro named @racket[macro-id]; equivalent to the following:
 ]
 
 }
+
+@defform[(define-syntax-parser macro-id parse-option ... clause ...+)]{
+
+Defines a macro named @racket[macro-id]; equivalent to:
+
+@racketblock[
+(define-syntax macro-id
+  (syntax-parser parse-option ... clause ...))
+]
+
+@myexamples[
+(define-syntax-parser fn3
+  [(fn3 x:id rhs:expr)
+   #'(lambda (x) rhs)]
+  [(fn3 x:id y:id rhs:expr)
+   #'(lambda (x y) rhs)])
+((fn3 x x) 17)
+((fn3 a b (+ a b)) 3 4)
+(fn3 1 2)
+(fn3 a #:b 'c)
+]}
+

racket/collects/syntax/parse/define.rkt

@@ -3,6 +3,7 @@
                      syntax/parse
                      "private/sc.rkt"))
 (provide define-simple-macro
+         define-syntax-parser
          (for-syntax (all-from-out syntax/parse)))
 
 (define-syntax (define-simple-macro stx)
@@ -12,3 +13,8 @@
          (syntax-parser/template
           #,((make-syntax-introducer) stx)
           [pattern . body]))]))
+
+(define-simple-macro (define-syntax-parser macro:id option-or-clause ...)
+  (define-syntax macro
+    (syntax-parser option-or-clause ...)))
+