stricter atomizing

quad/quad/atomize.rkt

@@ -1,7 +1,8 @@
-#lang sugar/debug racket/base
-(require racket/contract racket/match racket/list txexpr racket/dict
+#lang debug racket/base
+(require racket/contract racket/match racket/list txexpr racket/dict sugar/list racket/function
          "quad.rkt" "qexpr.rkt" "param.rkt")
 (provide (all-defined-out))
+(module+ test (require rackunit))
 
 (define (update-with base-hash . update-hashes)
   ;; starting with base-hash, add or update keys found in update-hashes
@@ -12,26 +13,48 @@
    ((hasheq 'foo "bar" 'zim "zam") . update-with .  (hasheq 'zim "BANG") (hasheq 'toe "jam") (hasheq 'foo "zay"))
    '#hasheq((zim . "BANG") (foo . "zay") (toe . "jam"))))
 
+(define (merge-whitespace aqs)
+  ;; collapse each sequence of whitespace aqs to the first one, and make it a space
+  ;; also drop leading & trailing whitespaces
+  ;; (same behavior as web browsers)
+  (define (white-aq? aq) (char-whitespace? (car (qe aq))))
+   (let loop ([acc null][aqs aqs])
+     (if (null? aqs)
+         (trimf (flatten acc) white-aq?)
+         (let*-values ([(ws rest) (splitf-at aqs white-aq?)]
+                       [(bs rest) (splitf-at rest (negate white-aq?))])
+           (loop (list acc (match ws
+                             [(list ($quad attrs elems) rest ...) (break attrs #\space)]
+                             [else null]) bs) rest)))))
+
+(module+ test
+  (check-equal? (merge-whitespace (list (q #\space) (q #\newline) (q #\H) (q #\space) (q #\newline) (q #\space) (q #\i) (q #\newline)))
+                (list (q #\H) (b #\space) (q #\i))))
+
 (define/contract (atomize qx)
   ;; normalize a quad by reducing it to one-character quads.
   ;; propagate attrs downward.
   (quad? . -> . (listof atomic-quad?))
-  (let loop ([x qx][attrs (current-default-attrs)])
-    (match x
-      [(? char? c) (list (q attrs c))]
-      [(? string?) (append* (for/list ([c (in-string x)]) ;; strings are exploded
-                                      (loop c attrs)))]
-      [($quad this-attrs elems) ;; qexprs with attributes are recursed
-       (define merged-attrs (attrs . update-with . this-attrs))
-       (append* (for/list ([elem (in-list elems)])
-                          (loop elem merged-attrs)))]
-      [else (raise-argument-error 'atomize "valid item" x)])))
+  (define atomic-quads
+    (let loop ([x qx][attrs (current-default-attrs)])
+      (match x
+        [(? char? c) (list (q attrs c))]
+        [(? string?) (append* (for/list ([c (in-string x)]) ;; strings are exploded
+                                        (loop c attrs)))]
+        [($quad this-attrs elems) ;; qexprs with attributes are recursed
+         (define merged-attrs (attrs . update-with . this-attrs))
+         (append* (for/list ([elem (in-list elems)])
+                            (loop elem merged-attrs)))]
+        [else (raise-argument-error 'atomize "valid item" x)])))
+  (merge-whitespace atomic-quads))
 
 (module+ test
   (require rackunit)
   (check-equal? (atomize (q "Hi")) (list (q #\H) (q #\i)))
-  (check-equal? (atomize (q "Hi " (q "You"))) (list (q #\H) (q #\i) (q #\space) (q #\Y) (q #\o) (q #\u)))
+  (check-equal? (atomize (q "Hi " (q "You"))) (list (q #\H) (q #\i) (b #\space) (q #\Y) (q #\o) (q #\u)))
   (check-exn exn:fail:contract? (λ () (atomize #t)))
+  (check-equal? (atomize (q "H i")) (list (q #\H) (b #\space) (q #\i)))
+  (check-equal? (atomize (q "H \n\n i")) (list (q #\H) (b #\space) (q #\i))) ;; collapse whitespace to single
 
   ;; with attributes
   (check-equal? (atomize (q (hasheq 'k "v") "Hi")) (list (q (hasheq 'k "v") #\H) (q (hasheq 'k "v") #\i)))
@@ -39,15 +62,15 @@
                 (list
                  ($quad '#hasheq((k . "v")) '(#\H))
                  ($quad '#hasheq((k . "v")) '(#\i))
-                 ($quad '#hasheq((k . "v")) '(#\space))
+                 ($break '#hasheq((k . "v")) '(#\space))
                  ($quad '#hasheq((k . "v")) '(#\Y))
                  ($quad '#hasheq((k . "v")) '(#\o))
                  ($quad '#hasheq((k . "v")) '(#\u))))
-  (check-equal? (atomize (q (hasheq 'k1 "v1" 'k2 42) "Hi " (q (hasheq 'k1 "v2" 'k3 "foo") "You")))
+  (check-equal? (atomize (q (hasheq 'k1 "v1" 'k2 42) "Hi \n\n" (q (hasheq 'k1 "v2" 'k3 "foo") "\n \nYou")))
                 (list
                  ($quad '#hasheq((k1 . "v1") (k2 . 42)) '(#\H))
                  ($quad '#hasheq((k1 . "v1") (k2 . 42)) '(#\i))
-                 ($quad '#hasheq((k1 . "v1") (k2 . 42)) '(#\space))
+                 ($break '#hasheq((k1 . "v1") (k2 . 42)) '(#\space))
                  ($quad '#hasheq((k1 . "v2") (k2 . 42) (k3 . "foo")) '(#\Y))
                  ($quad '#hasheq((k1 . "v2") (k2 . 42) (k3 . "foo")) '(#\o))
                  ($quad '#hasheq((k1 . "v2") (k2 . 42) (k3 . "foo")) '(#\u)))))

quad/quad/quad.rkt

@@ -8,16 +8,16 @@
 (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 . xs)
+(define (quad #:type [type $quad] . xs)
   (match xs
-    [(list #f xs ...) (apply quad (hasheq) xs)]
-    [(list (? quad-attrs? attrs) (? quad-elem? elems) ...) ($quad attrs elems)]
-    [(list (? quad-elem? elems) ...) (apply quad #f elems)]
+    [(list #f xs ...) (apply quad #:type type (hasheq) xs)]
+    [(list (? quad-attrs? attrs) (? quad-elem? elems) ...) (type attrs elems)]
+    [(list (? quad-elem? elems) ...) (apply quad #:type type #f elems)]
     [else (error 'bad-quad-input)]))
 (define (quads? xs) (and (pair? xs) (andmap quad? xs)))
 (define (atomic-quad? x) (and (quad? x) (match (qe x)
-                                         [(list (? char?)) #t]
-                                         [else #f])))
+                                          [(list (? char?)) #t]
+                                          [else #f])))
 (define (atomic-quads? xs) (and (pair? xs) (andmap atomic-quad? xs)))
 (module+ test
   (check-true (atomic-quad? ($quad '#hasheq() '(#\H))))
@@ -31,3 +31,7 @@
 (define qs? quads?)
 (define qa quad-attrs)
 (define qe quad-elems)
+
+(struct $break $quad () #:transparent)
+(define (break . xs) (apply quad #:type $break xs))
+(define b break)