From 42c64ba04c4d2f5d94646b580cf2922b0349132a Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Wed, 2 Jan 2019 07:54:14 -0800
Subject: [PATCH] classy

---
 quad/quad/quad-class.rkt | 91 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 quad/quad/quad-class.rkt

diff --git a/quad/quad/quad-class.rkt b/quad/quad/quad-class.rkt
new file mode 100644
index 00000000..7038b62a
--- /dev/null
+++ b/quad/quad/quad-class.rkt
@@ -0,0 +1,91 @@
+#lang debug racket/base
+(require racket/match racket/promise racket/dict racket/class)
+(provide (all-defined-out))
+(module+ test (require rackunit))
+
+(define quad%
+  (class object%
+    (super-new)
+    (init-field [@attrs null] [@elems null])
+    ;; why 'nw and 'ne as defaults for in and out points:
+    ;; if size is '(0 0), 'nw and 'ne are the same point,
+    ;; and everything piles up at the origin
+    ;; if size is otherwise, the items don't pile up (but rather lay out in a row)
+    (field [@in 'nw]
+           [@out 'ne]
+           [@inner #f]
+           [@printable #f]
+           [@size '(0 0)]
+           [@offset '(0 0)]
+           [@origin '(0 0)])
+    
+    (define/public-final (elems) @elems)
+    (define/public-final (attrs) @attrs)
+    (define/public-final (in) @in)
+    (define/public-final (out) @out)
+    (define/public-final (inner) (or @inner (in)))
+    (define/public-final (origin) @origin)
+    (define/public-final (set-origin! val) (set! @origin val))
+    (define/public (offset [signal #f]) @offset)
+    
+    (define/public (printable? [signal #f])
+      (match (or @printable
+                 (match @elems
+                   [(list (and (? char?) (? char-whitespace?)))
+                    #:when (memq signal '(start end)) #false]
+                   [else #true]))
+        [(? procedure? proc) (proc signal)]
+        [(? promise? prom) (force prom)]
+        [val val]))
+
+    (define/public (size)
+      (match @size
+        [(? procedure? proc) (proc)]
+        [(? promise? prom) (force prom)]
+        [val val]))
+    
+    (define/public (draw [surface #f])
+      (for-each (λ (e) (draw e surface)) @elems))))
+
+(define (quad? x) (is-a? x quad%))
+(define (quad-attrs? x) (and (hash? x) (hash-eq? x)))
+(define (quad-elem? x) (or (char? x) (string? x) (quad? x)))
+(define (quad-elems? xs) (and (pair? xs) (andmap quad-elem? xs)))
+(define (quad #:type [type quad%] . xs)
+  (match xs
+    [(list #f xs ...) (apply quad #:type type (hasheq) xs)]
+    [(list (list (? symbol? sym) rest ...) (? quad-elem? elems) ...)
+     (make-object type (apply hasheq (cons sym rest)) elems)]
+    [(list (? dict? attrs) (? quad-elem? elems) ...)
+     (make-object type (for/hasheq ([(k v) (in-dict attrs)])
+                         (values k v)) elems)]
+    [(list (? quad-attrs? attrs) (? quad-elem? elems) ...) (make-object type attrs elems)]
+    [(list (? quad-elem? elems) ...) (apply quad #:type type #f elems)]
+    [else (error 'bad-quad-input)]))
+(define q quad)
+(define (quads? xs) (andmap quad? xs))
+(define (atomic-quad? x) (and (quad? x) (match (send x elems)
+                                          [(list (? char?)) #t]
+                                          [else #f])))
+(define (atomic-quads? xs) (andmap atomic-quad? xs))
+
+(module+ test
+  (check-true (atomic-quad? (make-object quad% '#hasheq() '(#\H))))
+  (check-true (atomic-quads? (list (make-object quad% '#hasheq() '(#\H))))))
+
+
+
+
+(define break% (class quad% (super-new)))
+(define (break . xs) (apply quad #:type break% xs))
+(define b break)
+
+
+
+(module+ test
+  (define x (make-object
+                (class quad%
+                  (super-new)
+                  (define/override (draw [surface #f])
+                    (println "foo"))) '(#\H #\e #\l #\o)))
+  (send x draw))