it does...something!

kaitai/info.rkt

@@ -2,6 +2,6 @@
 
 (define version "0.0.1")
 (define collection "kaitai")
-(define deps '("base" "yaml"))
+(define deps '("base" "yaml" "binaryio-lib"))
 (define test-omit-paths '("info.rkt"))
 ; (define scribblings '(("kaitai.scrbl"))')

kaitai/main.rkt

@@ -1,15 +1,45 @@
 #lang racket/base
 
-(provide (rename-out [kaitai-module-begin #%module-begin]))
+(require (for-syntax racket/base racket/list))
+(provide (rename-out [kaitai:module-begin #%module-begin])
+         (except-out (all-from-out racket/base) #%module-begin))
 
-(define-syntax-rule (kaitai-module-begin EXPR ...)
-  (#%module-begin
-   (displayln `(EXPR ...))))
+;; meow
+
+;; makes a syntax error raiser
+(define-for-syntax (rse msg)
+  (lambda () (raise-syntax-error #f msg)))
+
+;; converts a ksy id to a racket id
+;; maps _ to -
+(define-for-syntax (kaitai-str->sym str)
+  (string->symbol (regexp-replace* #px"_" str "-")))
+
+;; generates struct definitions
+(define-for-syntax (gen-struct top [given-id #f])
+  (define id (or given-id (hash-ref (hash-ref top "meta" (hash)) "id"
+                                    (rse "type has no meta.id and none was provided"))))
+  (define id-sym (kaitai-str->sym id))
+  (define seq (hash-ref top "seq" (rse "form must have a seq element")))
+  (define instances (hash-ref top "instances" (hash)))
+  #`((provide [struct-out #,id-sym])
+     (struct #,id-sym
+      [#,@(map (lambda (a) (kaitai-str->sym (hash-ref a "id" (rse "seq element has no id"))))
+               seq)] #:transparent)))
+
+;; language infrastructure
+
+(define-syntax (kaitai:module-begin stx)
+  (define body (second (syntax-e stx)))
+  (define top-struct (gen-struct (syntax->datum body)))
+  ; (displayln top-struct)
+  #`(#%module-begin
+     #,@top-struct))
 
 (module reader syntax/module-reader
   #:read kaitai-read
   #:read-syntax kaitai-read
-  #:language "."
+  #:language 'kaitai
 
   (require yaml)