wf-validate: begin url rebasing work

scripts/writefreely-validate

@@ -3,9 +3,13 @@
 
 (require json
          racket/list
+         racket/match
          racket/port
          racket/pretty)
 
+(define link-base (make-parameter #f))
+(define embed-base (make-parameter #f))
+
 (define current-header (make-parameter #f))
 
 (define (check-block blk)
@@ -29,11 +33,27 @@
       (check-block thing))
     (for-each check-any (hash-values thing))))
 
+(define (hash-ref* table keys)
+  (match keys
+    ['() table]
+    [(cons key rst) (hash-ref* (hash-ref table key #f) rst)]))
+
 (define (check-ast doc-ast)
+  (link-base (hash-ref* doc-ast '(meta wf-link-base c)))
+  (embed-base (hash-ref* doc-ast '(meta wf-embed-base c)))
   (check-any (hash-ref doc-ast 'blocks)))
 
+(define (transform-ast doc-ast)
+  ;; todo
+  doc-ast)
+
 (module+ main
-  (define doc-ast (read-json))
-  (current-header "<top level>")
-  (check-ast doc-ast)
-  (write-json doc-ast))
+  (require racket/cmdline)
+
+  (command-line
+    #:program "writefreely-validate"
+    #:args (doctype)
+    (define doc-ast (read-json))
+    (current-header "<top level>")
+    (check-ast doc-ast)
+    (write-json (transform-ast doc-ast))))