Add Whalesong specific versions of letrec and letrec-values to avoid the undefined value

whalesong/lang/kernel.rkt

@@ -37,6 +37,27 @@
 (provide current-print-mode)
 
 
+;; Custom letrec and letrec-values in order to avoid running
+;; into the (in Racket) newly introduced undefined value.
+
+(provide letrec letrec-values)  
+(define-syntax (letrec stx)
+  (syntax-case stx ()
+    [(_ ([id expr] ...) body ...)
+     (syntax/loc stx
+       (let ([id '**undefined**] ...)
+         (set! id expr) ...
+         (let () body ...)))]))
+
+(define-syntax (letrec-values stx)
+  (syntax-case stx ()
+    [(_ ([(id ...) expr] ...) body ...)
+     (syntax/loc stx
+       (let ([id '**undefined**] ... ...)
+         (set!-values (id ...) expr) ...
+         (let () body ...)))]))
+
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Primitive function stubs
 
@@ -264,26 +285,26 @@
  current-continuation-marks
  continuation-mark-set->list
  
-;;  continuation-mark-set?
+ ;;  continuation-mark-set?
-;;  continuation-mark-set->list
+ ;;  continuation-mark-set->list
  
-;;  struct-constructor-procedure?
+ ;;  struct-constructor-procedure?
-;;  struct-predicate-procedure?
+ ;;  struct-predicate-procedure?
-;;  struct-accessor-procedure?
+ ;;  struct-accessor-procedure?
-;;  struct-mutator-procedure?
+ ;;  struct-mutator-procedure?
  
-;;  make-arity-at-least
+ ;;  make-arity-at-least
-;;  arity-at-least?
+ ;;  arity-at-least?
-;;  arity-at-least-value
+ ;;  arity-at-least-value
  
  
-;;  compose
+ ;;  compose
-;;  current-inexact-milliseconds
+ ;;  current-inexact-milliseconds
-;;  current-seconds
+ ;;  current-seconds
  void
  random
-;;  sleep
+ ;;  sleep
-;;  (identity -identity)
+ ;;  (identity -identity)
  
  raise  
  error
@@ -297,10 +318,10 @@
  make-exn:fail:contract:variable
  make-exn:fail:contract:divide-by-zero
  
-;;  exn?
+ ;;  exn?
-;;  exn:fail:contract:arity?
+ ;;  exn:fail:contract:arity?
-;;  exn:fail:contract:variable?
+ ;;  exn:fail:contract:variable?
-;;  exn:fail:contract:divide-by-zero?
+ ;;  exn:fail:contract:divide-by-zero?
  exn:fail?
  exn:fail:contract?
  exn:fail:contract:arity?
@@ -353,32 +374,32 @@
  procedure-arity-includes?
  procedure-rename
  ;;  (undefined? -undefined?)
-;;  immutable?
+ ;;  immutable?
-void?
+ void?
-symbol?
+ symbol?
-string?
+ string?
-char?
+ char?
-boolean?
+ boolean?
-vector?
+ vector?
-struct?
+ struct?
-;;  bytes?
+ ;;  bytes?
-byte?
+ byte?
-number?
+ number?
-complex?
+ complex?
-real?
+ real?
-rational?
+ rational?
-integer?
+ integer?
-exact-integer?
+ exact-integer?
-exact?
+ exact?
-exact-nonnegative-integer?
+ exact-nonnegative-integer?
-inexact?
+ inexact?
-odd?
+ odd?
-even?
+ even?
-zero?
+ zero?
-positive?
+ positive?
-negative?
+ negative?
-box?
+ box?
-;;  hash?
+ ;;  hash?
  
  equal?
  eqv?
@@ -415,7 +436,7 @@ box?
  length
  list*
  list-ref
-;;  list-tail
+ ;;  list-tail
  append
  reverse
  for-each
@@ -429,18 +450,18 @@ box?
  assq
  assv
  assoc
-;;  sort
+ ;;  sort
  box
-;;  box-immutable
+ ;;  box-immutable
  unbox
  set-box!
-;;  make-hash
+ ;;  make-hash
-;;  make-hasheq
+ ;;  make-hasheq
-;;  hash-set!
+ ;;  hash-set!
-;;  hash-ref
+ ;;  hash-ref
-;;  hash-remove!
+ ;;  hash-remove!
-;;  hash-map
+ ;;  hash-map
-;;  hash-for-each
+ ;;  hash-for-each
  make-string
  string
  string-length
@@ -467,24 +488,24 @@ box?
  format
  printf
  fprintf
-;;  string->immutable-string
+ ;;  string->immutable-string
  string-set!
-;;  string-fill!
+ ;;  string-fill!
-;;  make-bytes
+ ;;  make-bytes
-;;  bytes
+ ;;  bytes
-;;  bytes->immutable-bytes
+ ;;  bytes->immutable-bytes
-;;  bytes-length
+ ;;  bytes-length
-;;  bytes-ref
+ ;;  bytes-ref
-;;  bytes-set!
+ ;;  bytes-set!
-;;  subbytes
+ ;;  subbytes
-;;  bytes-copy
+ ;;  bytes-copy
-;;  bytes-fill!
+ ;;  bytes-fill!
-;;  bytes-append
+ ;;  bytes-append
-;;  bytes->list
+ ;;  bytes->list
-;;  list->bytes
+ ;;  list->bytes
-;;  bytes=?
+ ;;  bytes=?
-;;  bytes<?
+ ;;  bytes<?
-;;  bytes>?
+ ;;  bytes>?
  make-vector
  vector
  vector-length