From d6fff41bb8b3631faa5031ec3058f095dcee1549 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Mon, 17 Dec 2018 11:42:51 -0800
Subject: [PATCH] new notation

---
 fontland/fontland/directory.rkt    |  7 +++----
 fontland/fontland/font.rkt         |  4 ++--
 fontland/fontland/table-stream.rkt |  5 +----
 fontland/fontland/table/loca.rkt   | 19 ++++++++-----------
 4 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/fontland/fontland/directory.rkt b/fontland/fontland/directory.rkt
index 5cf4cad8..6b10abb2 100644
--- a/fontland/fontland/directory.rkt
+++ b/fontland/fontland/directory.rkt
@@ -53,16 +53,15 @@ https://github.com/mbutterick/fontkit/blob/master/src/tables/directory.js
               'rangeShift (- (* numTables 16) searchRange))
   this-val)
 
-(define Directory (+xstruct 'tag (+xsymbol #:length 4)
+(define Directory (+xstruct #:pre-encode directory-pre-encode
+                            #:post-decode directory-post-decode
+                            'tag (+xsymbol #:length 4)
                             'numTables uint16be
                             'searchRange uint16be
                             'entrySelector uint16be
                             'rangeShift uint16be
                             'tables (+xarray #:type table-entry #:length 'numTables)))
 
-(set-pre-encode! Directory directory-pre-encode)
-(set-post-decode! Directory directory-post-decode)
-
 (define (directory-decode ip [options (mhash)])
   (decode Directory ip))
 
diff --git a/fontland/fontland/font.rkt b/fontland/fontland/font.rkt
index bf0e8188..34ec8a25 100644
--- a/fontland/fontland/font.rkt
+++ b/fontland/fontland/font.rkt
@@ -8,6 +8,7 @@
          "db.rkt"
          "struct.rkt"
          "table-stream.rkt"
+         racket/class
          xenomorph
          racket/match
          sugar/unstable/dict
@@ -35,8 +36,7 @@ https://github.com/mbutterick/fontkit/blob/master/src/TTFFont.js
 (define (+ttf-font port
                    [decoded-tables (mhash)]
                    [src (path->string (object-name port))]
-                   [directory (delay (parameterize ([current-parent (mhash '_startOffset 0)])
-                                       (xdecode Directory port)))]
+                   [directory (delay (decode Directory port #:parent (mhash '_startOffset 0)))]
                    [ft-face (delay (and src (FT_New_Face (force ft-library) src)))]
                    [hb-font (delay (and src (hb_ft_font_create (force ft-face))))]
                    [hb-buf (delay (hb_buffer_create))]
diff --git a/fontland/fontland/table-stream.rkt b/fontland/fontland/table-stream.rkt
index 2356fdfa..5285bd59 100644
--- a/fontland/fontland/table-stream.rkt
+++ b/fontland/fontland/table-stream.rkt
@@ -24,8 +24,6 @@
   (hash-has-key? (· directory tables) (match tag
                                              [(? bytes?) (string->symbol (bytes->string/latin-1 tag))]
                                              [_ tag])))
-  
-
 
 (define (get-table this table-tag)
   (unless (has-table? this table-tag)
@@ -48,6 +46,5 @@
   (pos (ttf-font-port this) (· table offset))
   (define table-bytes (open-input-bytes (peek-bytes (· table length) 0 (ttf-font-port this))))
   (define table-decoder (hash-ref table-codecs table-tag))
-  (parameterize ([current-parent this])
-    (decode table-decoder table-bytes)))
+  (decode table-decoder table-bytes #:parent this))
 
diff --git a/fontland/fontland/table/loca.rkt b/fontland/fontland/table/loca.rkt
index ce151565..dc4450a7 100644
--- a/fontland/fontland/table/loca.rkt
+++ b/fontland/fontland/table/loca.rkt
@@ -37,24 +37,21 @@ https://github.com/mbutterick/fontkit/blob/master/src/tables/loca.js
   val)
 
 (define loca (+xversioned-struct
+              #:pre-encode loca-pre-encode
+              #:post-decode loca-post-decode
               ;; todo: address ugliness to cross-ref head table from ttffont
               (λ (o) (hash-ref (force (ttf-font-get-head-table-proc o)) 'indexToLocFormat)) 
               (dictify
                0 (dictify 'offsets (+xarray #:type uint16be))
                1 (dictify 'offsets (+xarray #:type uint32be)))))
 
-(set-pre-encode! loca loca-pre-encode)
-(set-post-decode! loca loca-post-decode)
-
 (define loca-v0 (+xversioned-struct
-              ;; todo: address ugliness to cross-ref head table from ttffont
-              0 
-              (dictify
-               0 (dictify 'offsets (+xarray #:type uint16be))
-               1 (dictify 'offsets (+xarray #:type uint32be)))))
-
-(set-pre-encode! loca-v0 loca-pre-encode)
-(set-post-decode! loca-v0 loca-post-decode)
+                 #:pre-encode loca-pre-encode
+                 #:post-decode loca-post-decode
+                 0 
+                 (dictify
+                  0 (dictify 'offsets (+xarray #:type uint16be))
+                  1 (dictify 'offsets (+xarray #:type uint32be)))))
 
 (module+ test
   (require rackunit racket/serialize)