sun lunch

main-helper.rkt

@@ -4,6 +4,8 @@
 (require (planet mb/pollen/tools)
          (planet mb/pollen/world))
 
+(module+ test (require rackunit))
+
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Look for a EXTRAS_DIR directory local to the source file.
@@ -65,6 +67,9 @@
           (match-let-values ([(_ here-name _) (split-path ccr)])
                             (path->string (remove-all-ext here-name)))))))
 
+(module+ test
+  (check-equal? (get-here) "test-main-helper"))
+
 ; then, apply a separate syntax transform to the identifier itself
 ; can't do this in one step, because if the macro goes from identifier to function definition,
 ; macro processor will evaluate the body at compile-time, not runtime.
@@ -82,14 +87,11 @@
          (set! meta-list (cons x meta-list))
          empty)]
       [(named-xexpr? x) ; handle named-xexpr
-       (let-values([(name attr body) (xexplode x)]) 
-         (make-xexpr name attr (&split-metas body)))]
+       (let-values([(name attr body) (break-named-xexpr x)]) 
+         (make-named-xexpr name attr (&split-metas body)))]
       [(list? x) (map &split-metas x)]
       [else x]))
   (values (remove-empty (&split-metas body)) (reverse meta-list))) 
 
 (provide (all-defined-out))
 
-(module+ test
-  (require rackunit)
-  (check-equal? (get-here) "test-main-helper"))

readability.rkt

@@ -2,6 +2,7 @@
 (require racket/contract)
 (require (only-in racket/list empty?))
 (require (only-in racket/format ~a))
+(module+ test (require rackunit))
 
 (provide (all-defined-out))
 
@@ -16,13 +17,49 @@
     [(char? x) (~a x)]
     [else (error (format "Can't make ~a into string" x))]))
 
-
 (module+ test
-  (require rackunit)
   (check-equal? (as-string '()) "")
   (check-equal? (as-string 'foo) "foo")
   (check-equal? (as-string 123) "123")
   (define file-name-as-text "foo.txt")
   (check-equal? (as-string (string->path file-name-as-text)) file-name-as-text)
-  (check-equal? (as-string #\¶) "¶")
+  (check-equal? (as-string #\¶) "¶"))
+
+
+;; general way of coercing to a list
+(define (as-list x)
+  (any/c . -> . list?)
+  (cond 
+    [(list? x) x]
+    [(vector? x) (vector->list x)]
+    [else (list x)])) 
+
+(module+ test
+  (check-equal? (as-list '(1 2 3)) '(1 2 3))
+  (check-equal? (as-list (list->vector '(1 2 3))) '(1 2 3))
+  (check-equal? (as-list "foo") (list "foo")))
+
+;; general way of asking for length
+(define (len x)
+  (any/c . -> . integer?)
+  (cond
+    [(list? x) (length x)]
+    [(string? x) (string-length x)]
+    [(symbol? x) (len (as-string x))]
+    [(vector? x) (vector-length x)]
+    [(hash? x) (len (hash-keys x))]
+    [else #f]))
+
+(module+ test
+  (check-equal? (len '(1 2 3)) 3)
+  (check-not-equal? (len '(1 2)) 3) ; len 2
+  (check-equal? (len "foo") 3)
+  (check-not-equal? (len "fo") 3) ; len 2
+  (check-equal? (len 'foo) 3)
+  (check-not-equal? (len 'fo) 3) ; len 2
+  (check-equal? (len (list->vector '(1 2 3))) 3)
+  (check-not-equal? (len (list->vector '(1 2))) 3) ; len 2
+  (check-equal? (len (make-hash '((a 1) (b 2) (c 3)))) 3)
+  (check-not-equal? (len (make-hash '((a 1) (b 2) (b 3)))) 3) ; len 2
+
   )

tools.rkt

@@ -3,6 +3,7 @@
 (require racket/contract racket/match)
 (require (only-in racket/path filename-extension))
 (require (only-in racket/format ~a))
+(require (only-in racket/list empty empty? second filter-not))
 (require (only-in xml xexpr?))
 (provide (all-defined-out))
 
@@ -109,3 +110,74 @@
   (check-false (named-xexpr? '(p "foo" "bar" ((key "value"))))) ; malformed
   (check-false (named-xexpr? '("p" "foo" "bar"))) ; no name
   (check-false (named-xexpr? '(p 123)))) ; content is a number
+
+;; helper for comparison of values
+;; normal function won't work for this. Has to be syntax-rule
+(define-syntax-rule (values->list vs)
+  (call-with-values (λ() vs) list))
+
+
+;; create named-xexpr from parts (opposite of break-named-xexpr)
+(define/contract (make-named-xexpr name [attr empty] [content empty])
+  ((symbol?) (xexpr-attr? xexpr-content?) . ->* . named-xexpr?)
+  (filter-not empty? `(,name ,attr ,@content)))
+
+(module+ test
+  (check-equal? (make-named-xexpr 'p) '(p))
+  (check-equal? (make-named-xexpr 'p '((key "value"))) '(p ((key "value"))))
+  (check-equal? (make-named-xexpr 'p empty '("foo" "bar")) '(p "foo" "bar"))
+  (check-equal? (make-named-xexpr 'p '((key "value")) (list "foo" "bar")) 
+                '(p ((key "value")) "foo" "bar")))
+
+
+;; decompose named-xexpr into parts (opposite of make-named-xexpr)
+(define/contract (break-named-xexpr nx)
+  (named-xexpr? . -> . (values symbol? xexpr-attr? xexpr-content?))
+  (match 
+      ; named-xexpr may or may not have attr
+      ; if not, add empty attr so that decomposition only handles one case
+      (match nx
+        [(list _ (? xexpr-attr?) _ ...) nx]
+        [else `(,(car nx) ,empty ,@(cdr nx))])
+    [(list name attr content ...) (values name attr content)]))
+
+(module+ test
+  (check-equal? (values->list (break-named-xexpr '(p))) 
+                (values->list (values 'p empty empty)))
+  (check-equal? (values->list (break-named-xexpr '(p "foo"))) 
+                (values->list (values 'p empty '("foo"))))
+  (check-equal? (values->list (break-named-xexpr '(p ((key "value"))))) 
+                (values->list (values 'p '((key "value")) empty)))
+  (check-equal? (values->list (break-named-xexpr '(p ((key "value")) "foo"))) 
+                (values->list (values 'p '((key "value")) '("foo")))))
+
+
+;; apply filter proc recursively
+(define/contract (filter-tree proc tree)
+  (procedure? list? . -> . list?)
+  (define (remove-empty x)
+    (cond
+      [(list? x) (map remove-empty (filter-not empty? x))]
+      [else x]))
+  
+  (define (filter-tree-inner proc tree)
+    (cond
+      [(list? tree) (map (λ(item) (filter-tree-inner proc item)) tree)]
+      [else (if (proc tree) tree empty)]))
+  
+  (remove-empty (filter-tree-inner proc tree)))
+
+(module+ test
+  (check-equal? (filter-tree string? '(p)) empty)
+  (check-equal? (filter-tree string? '(p "foo" "bar")) '("foo" "bar"))
+  (check-equal? (filter-tree string? '(p "foo" (p "bar"))) '("foo" ("bar"))))
+
+;; apply filter-not proc recursively
+(define/contract (filter-not-tree proc tree)
+  (procedure? list? . -> . list?)
+  (filter-tree (λ(item) (not (proc item))) tree))
+
+(module+ test
+  (check-equal? (filter-not-tree string? '(p)) '(p))
+  (check-equal? (filter-not-tree string? '(p "foo" "bar")) '(p))
+  (check-equal? (filter-not-tree string? '(p "foo" (p "bar"))) '(p (p))))