add define/curry

from syntax-objects/Summer2021#5
cc @agj

define-curry/define-curry-test.rkt

@@ -0,0 +1,20 @@
+#lang racket/base
+(module+ test
+  (require rackunit racket/string syntax-parse-example/define-curry/define-curry)
+
+  (test-case "insert-between"
+    (define/curry (insert-between mid left right)
+      (string-join (list left mid right) ""))
+
+    (define dash-between (insert-between "-"))
+
+    (check-equal? (dash-between "left" "right") "left-right")
+    (check-equal? (((insert-between "-") "left") "right") "left-right")
+
+    (check-true
+      (string-suffix? (symbol->string (object-name insert-between))
+                      "6:4"))
+
+    (check-exn #rx"arity mismatch" ;; object name
+      (lambda () (insert-between 2 3 3 4 4 44))))
+)

define-curry/define-curry.rkt

@@ -0,0 +1,20 @@
+#lang racket
+(provide define/curry)
+(require (for-syntax syntax/parse))
+
+(begin-for-syntax
+  (define-syntax-class name-params
+    #:description "name and parameters clause"
+    (pattern (name:id params:id ...+)
+             #:fail-when (check-duplicate-identifier
+                          (syntax->list #'(params ...)))
+             "duplicate parameter name")))
+
+(define-syntax (define/curry stx)
+  (syntax-parse stx
+    [(_ np:name-params body ...+)
+     #`(define np.name
+         (curry
+           #,(syntax/loc stx
+               (λ (np.params ...) body ...))))]))
+

define-curry/define-curry.scrbl

@@ -0,0 +1,30 @@
+#lang syntax-parse-example
+@require[
+  (for-label racket/base syntax/parse syntax-parse-example/define-curry/define-curry)]
+
+@(define define-curry-eval
+   (make-base-eval '(require racket/string syntax-parse-example/define-curry/define-curry)))
+
+@title{@tt{define/curry}}
+@stxbee2021["agj" 5]
+
+@; =============================================================================
+
+@defmodule[syntax-parse-example/define-curry/define-curry]{}
+
+@defform[(define/curry (fn-id arg-id ...+) body ...+)]{
+  Defines an automatically currying procedure.
+
+  @examples[#:eval define-curry-eval
+    (define/curry (insert-between mid left right)
+      (string-join (list left mid right) ""))
+    (define dash-between (insert-between "-"))
+    (dash-between "left" "right")
+  ]
+
+  The macro uses @racket[syntax/loc] to give newly-defined functions
+  names that point to their definition rather than to the macro body.
+
+  @racketfile{define-curry.rkt}
+
+}

index.scrbl

@@ -19,6 +19,7 @@
 @include-example{first-class-or}
 @include-example{optional-assert}
 @include-example{make-variable}
+@include-example{define-curry}
 @include-example{cross-macro-communication}
 @include-example{let-star}
 @include-example{while-break}