0.8.0.24:

[sbcl.git] / src / code / loop.lisp

diff --git a/src/code/loop.lisp b/src/code/loop.lisp
index 1df85e1..4be06cb 100644 (file)
--- a/src/code/loop.lisp
+++ b/src/code/loop.lisp
@@ -326,13 +326,7 @@ code to be loaded.
                            (setf (gethash (car x) ht) (cadr x))))
                      ht))))
 \f
                            (setf (gethash (car x) ht) (cadr x))))
                      ht))))
 \f

-;;;; SETQ hackery
-
-(defvar *loop-destructuring-hooks*
-       nil
-  #!+sb-doc
-  "If not NIL, this must be a list of two things:
-a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.")
+;;;; SETQ hackery, including destructuring ("DESETQ")

 
 (defun loop-make-psetq (frobs)
   (and frobs
 
 (defun loop-make-psetq (frobs)
   (and frobs

@@ -345,19 +339,16 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 (defun loop-make-desetq (var-val-pairs)
   (if (null var-val-pairs)
       nil
 (defun loop-make-desetq (var-val-pairs)
   (if (null var-val-pairs)
       nil

-      (cons (if *loop-destructuring-hooks*
-               (cadr *loop-destructuring-hooks*)
-               'loop-really-desetq)
-           var-val-pairs)))
+      (cons 'loop-really-desetq var-val-pairs)))

 
 (defvar *loop-desetq-temporary*
        (make-symbol "LOOP-DESETQ-TEMP"))
 
 (sb!int:defmacro-mundanely loop-really-desetq (&environment env
 
 (defvar *loop-desetq-temporary*
        (make-symbol "LOOP-DESETQ-TEMP"))
 
 (sb!int:defmacro-mundanely loop-really-desetq (&environment env

-                                                 &rest var-val-pairs)
+                                              &rest var-val-pairs)

   (labels ((find-non-null (var)
   (labels ((find-non-null (var)

-            ;; see whether there's any non-null thing here
-            ;; recurse if the list element is itself a list
+            ;; See whether there's any non-null thing here. Recurse
+            ;; if the list element is itself a list.

             (do ((tail var)) ((not (consp tail)) tail)
               (when (find-non-null (pop tail)) (return t))))
           (loop-desetq-internal (var val &optional temp)
             (do ((tail var)) ((not (consp tail)) tail)
               (when (find-non-null (pop tail)) (return t))))
           (loop-desetq-internal (var val &optional temp)

@@ -365,17 +356,17 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
             (typecase var
               (null
                 (when (consp val)
             (typecase var
               (null
                 (when (consp val)

-                  ;; don't lose possible side-effects
+                  ;; Don't lose possible side effects.

                   (if (eq (car val) 'prog1)
                   (if (eq (car val) 'prog1)

-                      ;; these can come from psetq or desetq below.
-                      ;; throw away the value, keep the side-effects.
-                      ;;Special case is for handling an expanded POP.
-                      (mapcan #'(lambda (x)
-                                  (and (consp x)
-                                       (or (not (eq (car x) 'car))
-                                           (not (symbolp (cadr x)))
-                                           (not (symbolp (setq x (sb!xc:macroexpand x env)))))
-                                       (cons x nil)))
+                      ;; These can come from PSETQ or DESETQ below.
+                      ;; Throw away the value, keep the side effects.
+                      ;; Special case is for handling an expanded POP.
+                      (mapcan (lambda (x)
+                                (and (consp x)
+                                     (or (not (eq (car x) 'car))
+                                         (not (symbolp (cadr x)))
+                                         (not (symbolp (setq x (sb!xc:macroexpand x env)))))
+                                     (cons x nil)))

                               (cdr val))
                       `(,val))))
               (cons
                               (cdr val))
                       `(,val))))
               (cons

@@ -399,7 +390,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                                 ,@body)
                               `((let ((,temp ,val))
                                   ,@body))))
                                 ,@body)
                               `((let ((,temp ,val))
                                   ,@body))))

-                        ;; no cdring to do
+                        ;; no CDRing to do

                         (loop-desetq-internal car `(car ,val) temp)))))
               (otherwise
                 (unless (eq var val)
                         (loop-desetq-internal car `(car ,val) temp)))))
               (otherwise
                 (unless (eq var val)

@@ -432,36 +423,36 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 (defvar *loop-macro-environment*)
 
 ;;; This holds variable names specified with the USING clause.
 (defvar *loop-macro-environment*)
 
 ;;; This holds variable names specified with the USING clause.

-;;; See LOOP-NAMED-VARIABLE.
-(defvar *loop-named-variables*)
+;;; See LOOP-NAMED-VAR.
+(defvar *loop-named-vars*)

 
 ;;; LETlist-like list being accumulated for one group of parallel bindings.
 
 ;;; LETlist-like list being accumulated for one group of parallel bindings.

-(defvar *loop-variables*)
+(defvar *loop-vars*)

 
 

-;;; list of declarations being accumulated in parallel with *LOOP-VARIABLES*
+;;; list of declarations being accumulated in parallel with *LOOP-VARS*

 (defvar *loop-declarations*)
 
 ;;; This is used by LOOP for destructuring binding, if it is doing
 (defvar *loop-declarations*)
 
 ;;; This is used by LOOP for destructuring binding, if it is doing

-;;; that itself. See LOOP-MAKE-VARIABLE.
+;;; that itself. See LOOP-MAKE-VAR.

 (defvar *loop-desetq-crocks*)
 
 ;;; list of wrapping forms, innermost first, which go immediately
 ;;; inside the current set of parallel bindings being accumulated in
 (defvar *loop-desetq-crocks*)
 
 ;;; list of wrapping forms, innermost first, which go immediately
 ;;; inside the current set of parallel bindings being accumulated in

-;;; *LOOP-VARIABLES*. The wrappers are appended onto a body. E.g.,
+;;; *LOOP-VARS*. The wrappers are appended onto a body. E.g.,

 ;;; this list could conceivably have as its value
 ;;;   ((WITH-OPEN-FILE (G0001 G0002 ...))),
 ;;; this list could conceivably have as its value
 ;;;   ((WITH-OPEN-FILE (G0001 G0002 ...))),

-;;; with G0002 being one of the bindings in *LOOP-VARIABLES* (This is
+;;; with G0002 being one of the bindings in *LOOP-VARS* (This is

 ;;; why the wrappers go inside of the variable bindings).
 (defvar *loop-wrappers*)
 
 ;;; why the wrappers go inside of the variable bindings).
 (defvar *loop-wrappers*)
 

-;;; This accumulates lists of previous values of *LOOP-VARIABLES* and
+;;; This accumulates lists of previous values of *LOOP-VARS* and

 ;;; the other lists above, for each new nesting of bindings. See
 ;;; LOOP-BIND-BLOCK.
 (defvar *loop-bind-stack*)
 
 ;;; This is simply a list of LOOP iteration variables, used for
 ;;; checking for duplications.
 ;;; the other lists above, for each new nesting of bindings. See
 ;;; LOOP-BIND-BLOCK.
 (defvar *loop-bind-stack*)
 
 ;;; This is simply a list of LOOP iteration variables, used for
 ;;; checking for duplications.

-(defvar *loop-iteration-variables*)
+(defvar *loop-iteration-vars*)

 
 ;;; list of prologue forms of the loop, accumulated in reverse order
 (defvar *loop-prologue*)
 
 ;;; list of prologue forms of the loop, accumulated in reverse order
 (defvar *loop-prologue*)

@@ -499,14 +490,14 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 ;;; If not NIL, this is a temporary bound around the loop for holding
 ;;; the temporary value for "it" in things like "when (f) collect it".
 ;;; It may be used as a supertemporary by some other things.
 ;;; If not NIL, this is a temporary bound around the loop for holding
 ;;; the temporary value for "it" in things like "when (f) collect it".
 ;;; It may be used as a supertemporary by some other things.

-(defvar *loop-when-it-variable*)
+(defvar *loop-when-it-var*)

 
 ;;; Sometimes we decide we need to fold together parts of the loop,
 ;;; but some part of the generated iteration code is different for the
 ;;; first and remaining iterations. This variable will be the
 ;;; temporary which is the flag used in the loop to tell whether we
 ;;; are in the first or remaining iterations.
 
 ;;; Sometimes we decide we need to fold together parts of the loop,
 ;;; but some part of the generated iteration code is different for the
 ;;; first and remaining iterations. This variable will be the
 ;;; temporary which is the flag used in the loop to tell whether we
 ;;; are in the first or remaining iterations.

-(defvar *loop-never-stepped-variable*)
+(defvar *loop-never-stepped-var*)

 
 ;;; list of all the value-accumulation descriptor structures in the
 ;;; loop. See LOOP-GET-COLLECTION-INFO.
 
 ;;; list of all the value-accumulation descriptor structures in the
 ;;; loop. See LOOP-GET-COLLECTION-INFO.

@@ -520,7 +511,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
       (setq constant-value (eval new-form)))
     (when (and constantp expected-type)
       (unless (sb!xc:typep constant-value expected-type)
       (setq constant-value (eval new-form)))
     (when (and constantp expected-type)
       (unless (sb!xc:typep constant-value expected-type)

-       (loop-warn "The form ~S evaluated to ~S, which was not of the anticipated type ~S."
+       (loop-warn "~@<The form ~S evaluated to ~S, which was not of ~
+                    the anticipated type ~S.~:@>"

                   form constant-value expected-type)
        (setq constantp nil constant-value nil)))
     (values new-form constantp constant-value)))
                   form constant-value expected-type)
        (setq constantp nil constant-value nil)))
     (values new-form constantp constant-value)))

@@ -533,7 +525,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 (defvar *loop-duplicate-code*
        nil)
 
 (defvar *loop-duplicate-code*
        nil)
 

-(defvar *loop-iteration-flag-variable*
+(defvar *loop-iteration-flag-var*

        (make-symbol "LOOP-NOT-FIRST-TIME"))
 
 (defun loop-code-duplication-threshold (env)
        (make-symbol "LOOP-NOT-FIRST-TIME"))
 
 (defun loop-code-duplication-threshold (env)

@@ -543,6 +535,11 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
        ;; CLTL2, removed from ANSI standard) we could set these
        ;; values flexibly. Without DECLARATION-INFORMATION, we have
        ;; to set them to constants.
        ;; CLTL2, removed from ANSI standard) we could set these
        ;; values flexibly. Without DECLARATION-INFORMATION, we have
        ;; to set them to constants.

+       ;;
+       ;; except FIXME: we've lost all pretence of portability,
+       ;; considering this instead an internal implementation, so
+       ;; we're free to couple to our own representation of the
+       ;; environment.

        (speed 1)
        (space 1))
     (+ 40 (* (- speed space) 10))))
        (speed 1)
        (space 1))
     (+ 40 (* (- speed space) 10))))

@@ -622,7 +619,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                   (push (pop rafter) then)
                   (when (eq rbefore (cdr lastdiff)) (return)))
                 (unless flagvar
                   (push (pop rafter) then)
                   (when (eq rbefore (cdr lastdiff)) (return)))
                 (unless flagvar

-                  (push `(setq ,(setq flagvar *loop-iteration-flag-variable*)
+                  (push `(setq ,(setq flagvar *loop-iteration-flag-var*)

                                t)
                         else))
                 (push `(if ,flagvar ,(pify (psimp then)) ,(pify (psimp else)))
                                t)
                         else))
                 (push `(if ,flagvar ,(pify (psimp then)) ,(pify (psimp else)))

@@ -718,12 +715,10 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                        (setq n (+ n (estimate-code-size-1 (cadr l) env) 1))))
                     ((eq fn 'go) 1)
                     ((eq fn 'function)
                        (setq n (+ n (estimate-code-size-1 (cadr l) env) 1))))
                     ((eq fn 'go) 1)
                     ((eq fn 'function)

-                     ;; This skirts the issue of implementationally-defined
-                     ;; lambda macros by recognizing CL function names and
-                     ;; nothing else.
-                     (if (or (symbolp (cadr x))
-                             (and (consp (cadr x)) (eq (caadr x) 'setf)))
+                     (if (sb!int:legal-fun-name-p (cadr x))

                          1
                          1

+                         ;; FIXME: This tag appears not to be present
+                         ;; anywhere.

                          (throw 'duplicatable-code-p nil)))
                     ((eq fn 'multiple-value-setq)
                      (f (length (second x)) (cddr x)))
                          (throw 'duplicatable-code-p nil)))
                     ((eq fn 'multiple-value-setq)
                      (f (length (second x)) (cddr x)))

@@ -746,10 +741,9 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
       ((eq l (cdr *loop-source-code*)) (nreverse new))))
 
 (defun loop-error (format-string &rest format-args)
       ((eq l (cdr *loop-source-code*)) (nreverse new))))
 
 (defun loop-error (format-string &rest format-args)

-  (error "~?~%current LOOP context:~{ ~S~}."
-        format-string
-        format-args
-        (loop-context)))
+  (error 'sb!int:simple-program-error
+        :format-control "~?~%current LOOP context:~{ ~S~}."
+        :format-arguments (list format-string format-args (loop-context))))

 
 (defun loop-warn (format-string &rest format-args)
   (warn "~?~%current LOOP context:~{ ~S~}."
 
 (defun loop-warn (format-string &rest format-args)
   (warn "~?~%current LOOP context:~{ ~S~}."

@@ -770,14 +764,38 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                           specified-type required-type)))
        specified-type)))
 \f
                           specified-type required-type)))
        specified-type)))
 \f

+(defun subst-gensyms-for-nil (tree)
+  (declare (special *ignores*))
+  (cond
+    ((null tree) (car (push (gensym "LOOP-IGNORED-VAR-") *ignores*)))
+    ((atom tree) tree)
+    (t (cons (subst-gensyms-for-nil (car tree))
+            (subst-gensyms-for-nil (cdr tree))))))
+    
+(sb!int:defmacro-mundanely loop-destructuring-bind
+    (lambda-list arg-list &rest body)
+  (let ((*ignores* nil))
+    (declare (special *ignores*))
+    (let ((d-var-lambda-list (subst-gensyms-for-nil lambda-list)))
+      `(destructuring-bind ,d-var-lambda-list
+          ,arg-list
+        (declare (ignore ,@*ignores*))
+         ,@body))))
+
+(defun loop-build-destructuring-bindings (crocks forms)
+  (if crocks
+      `((loop-destructuring-bind ,(car crocks) ,(cadr crocks)
+        ,@(loop-build-destructuring-bindings (cddr crocks) forms)))
+      forms))
+

 (defun loop-translate (*loop-source-code*
                       *loop-macro-environment*
                       *loop-universe*)
   (let ((*loop-original-source-code* *loop-source-code*)
        (*loop-source-context* nil)
 (defun loop-translate (*loop-source-code*
                       *loop-macro-environment*
                       *loop-universe*)
   (let ((*loop-original-source-code* *loop-source-code*)
        (*loop-source-context* nil)

-       (*loop-iteration-variables* nil)
-       (*loop-variables* nil)
-       (*loop-named-variables* nil)
+       (*loop-iteration-vars* nil)
+       (*loop-vars* nil)
+       (*loop-named-vars* nil)

        (*loop-declarations* nil)
        (*loop-desetq-crocks* nil)
        (*loop-bind-stack* nil)
        (*loop-declarations* nil)
        (*loop-desetq-crocks* nil)
        (*loop-bind-stack* nil)

@@ -791,8 +809,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
        (*loop-after-epilogue* nil)
        (*loop-final-value-culprit* nil)
        (*loop-inside-conditional* nil)
        (*loop-after-epilogue* nil)
        (*loop-final-value-culprit* nil)
        (*loop-inside-conditional* nil)

-       (*loop-when-it-variable* nil)
-       (*loop-never-stepped-variable* nil)
+       (*loop-when-it-var* nil)
+       (*loop-never-stepped-var* nil)

        (*loop-names* nil)
        (*loop-collection-cruft* nil))
     (loop-iteration-driver)
        (*loop-names* nil)
        (*loop-collection-cruft* nil))
     (loop-iteration-driver)

@@ -804,9 +822,6 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                     ,(nreverse *loop-after-body*)
                     ,(nreconc *loop-epilogue*
                               (nreverse *loop-after-epilogue*)))))
                     ,(nreverse *loop-after-body*)
                     ,(nreconc *loop-epilogue*
                               (nreverse *loop-after-epilogue*)))))

-      (do () (nil)
-       (setq answer `(block ,(pop *loop-names*) ,answer))
-       (unless *loop-names* (return nil)))

       (dolist (entry *loop-bind-stack*)
        (let ((vars (first entry))
              (dcls (second entry))
       (dolist (entry *loop-bind-stack*)
        (let ((vars (first entry))
              (dcls (second entry))

@@ -818,16 +833,13 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
            (let ((forms (list answer)))
              ;;(when crocks (push crocks forms))
              (when dcls (push `(declare ,@dcls) forms))
            (let ((forms (list answer)))
              ;;(when crocks (push crocks forms))
              (when dcls (push `(declare ,@dcls) forms))

-             (setq answer `(,(cond ((not vars) 'locally)
-                                   (*loop-destructuring-hooks*
-                                    (first *loop-destructuring-hooks*))
-                                   (t
-                                    'let))
+             (setq answer `(,(if vars 'let 'locally)

                             ,vars
                             ,vars

-                            ,@(if crocks
-                                  `((destructuring-bind ,@crocks
-                                        ,@forms))
-                                forms)))))))
+                            ,@(loop-build-destructuring-bindings crocks
+                                                                 forms)))))))
+      (do () (nil)
+       (setq answer `(block ,(pop *loop-names*) ,answer))
+       (unless *loop-names* (return nil)))

       answer)))
 
 (defun loop-iteration-driver ()
       answer)))
 
 (defun loop-iteration-driver ()

@@ -862,17 +874,25 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
       (pop *loop-source-code*)
       (loop-error "LOOP source code ran out when another token was expected.")))
 
       (pop *loop-source-code*)
       (loop-error "LOOP source code ran out when another token was expected.")))
 

-(defun loop-get-progn ()
-  (do ((forms (list (loop-pop-source)) (cons (loop-pop-source) forms))
-       (nextform (car *loop-source-code*) (car *loop-source-code*)))
-      ((atom nextform)
-       (if (null (cdr forms)) (car forms) (cons 'progn (nreverse forms))))))
-

 (defun loop-get-form ()
   (if *loop-source-code*
       (loop-pop-source)
       (loop-error "LOOP code ran out where a form was expected.")))
 
 (defun loop-get-form ()
   (if *loop-source-code*
       (loop-pop-source)
       (loop-error "LOOP code ran out where a form was expected.")))
 

+(defun loop-get-compound-form ()
+  (let ((form (loop-get-form)))
+    (unless (consp form)
+      (loop-error "A compound form was expected, but ~S found." form))
+    form))
+
+(defun loop-get-progn ()
+  (do ((forms (list (loop-get-compound-form))
+              (cons (loop-get-compound-form) forms))
+       (nextform (car *loop-source-code*)
+                 (car *loop-source-code*)))
+      ((atom nextform)
+       (if (null (cdr forms)) (car forms) (cons 'progn (nreverse forms))))))
+

 (defun loop-construct-return (form)
   `(return-from ,(car *loop-names*) ,form))
 
 (defun loop-construct-return (form)
   `(return-from ,(car *loop-names*) ,form))
 

@@ -885,17 +905,26 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
   (setq *loop-emitted-body* t)
   (loop-pseudo-body form))
 
   (setq *loop-emitted-body* t)
   (loop-pseudo-body form))
 

-(defun loop-emit-final-value (form)
-  (push (loop-construct-return form) *loop-after-epilogue*)
+(defun loop-emit-final-value (&optional (form nil form-supplied-p))
+  (when form-supplied-p
+    (push (loop-construct-return form) *loop-after-epilogue*))

   (when *loop-final-value-culprit*
   (when *loop-final-value-culprit*

-    (loop-warn "The LOOP clause is providing a value for the iteration,~@
-               however one was already established by a ~S clause."
+    (loop-warn "The LOOP clause is providing a value for the iteration;~@
+               however, one was already established by a ~S clause."

               *loop-final-value-culprit*))
   (setq *loop-final-value-culprit* (car *loop-source-context*)))
 
 (defun loop-disallow-conditional (&optional kwd)
   (when *loop-inside-conditional*
     (loop-error "~:[This LOOP~;The LOOP ~:*~S~] clause is not permitted inside a conditional." kwd)))
               *loop-final-value-culprit*))
   (setq *loop-final-value-culprit* (car *loop-source-context*)))
 
 (defun loop-disallow-conditional (&optional kwd)
   (when *loop-inside-conditional*
     (loop-error "~:[This LOOP~;The LOOP ~:*~S~] clause is not permitted inside a conditional." kwd)))

+
+(defun loop-disallow-anonymous-collectors ()
+  (when (find-if-not 'loop-collector-name *loop-collection-cruft*)
+    (loop-error "This LOOP clause is not permitted with anonymous collectors.")))
+
+(defun loop-disallow-aggregate-booleans ()
+  (when (loop-tmember *loop-final-value-culprit* '(always never thereis))
+    (loop-error "This anonymous collection LOOP clause is not permitted with aggregate booleans.")))

 \f
 ;;;; loop types
 
 \f
 ;;;; loop types
 

@@ -977,60 +1006,64 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 ;;;; loop variables
 
 (defun loop-bind-block ()
 ;;;; loop variables
 
 (defun loop-bind-block ()

-  (when (or *loop-variables* *loop-declarations* *loop-wrappers*)
-    (push (list (nreverse *loop-variables*)
+  (when (or *loop-vars* *loop-declarations* *loop-wrappers*)
+    (push (list (nreverse *loop-vars*)

                *loop-declarations*
                *loop-desetq-crocks*
                *loop-wrappers*)
          *loop-bind-stack*)
                *loop-declarations*
                *loop-desetq-crocks*
                *loop-wrappers*)
          *loop-bind-stack*)

-    (setq *loop-variables* nil
+    (setq *loop-vars* nil

          *loop-declarations* nil
          *loop-desetq-crocks* nil
          *loop-wrappers* nil)))
 
          *loop-declarations* nil
          *loop-desetq-crocks* nil
          *loop-wrappers* nil)))
 

-(defun loop-make-variable (name initialization dtype
-                          &optional iteration-variable-p)
+(defun loop-var-p (name)
+  (do ((entry *loop-bind-stack* (cdr entry)))
+      (nil)
+    (cond
+      ((null entry) (return nil))
+      ((assoc name (caar entry) :test #'eq) (return t)))))
+
+(defun loop-make-var (name initialization dtype &optional iteration-var-p)

   (cond ((null name)
         (cond ((not (null initialization))
                (push (list (setq name (gensym "LOOP-IGNORE-"))
                            initialization)
   (cond ((null name)
         (cond ((not (null initialization))
                (push (list (setq name (gensym "LOOP-IGNORE-"))
                            initialization)

-                     *loop-variables*)
+                     *loop-vars*)

                (push `(ignore ,name) *loop-declarations*))))
        ((atom name)
                (push `(ignore ,name) *loop-declarations*))))
        ((atom name)

-        (cond (iteration-variable-p
-               (if (member name *loop-iteration-variables*)
+        (cond (iteration-var-p
+               (if (member name *loop-iteration-vars*)

                    (loop-error "duplicated LOOP iteration variable ~S" name)
                    (loop-error "duplicated LOOP iteration variable ~S" name)

-                   (push name *loop-iteration-variables*)))
-              ((assoc name *loop-variables*)
+                   (push name *loop-iteration-vars*)))
+              ((assoc name *loop-vars*)

                (loop-error "duplicated variable ~S in LOOP parallel binding"
                            name)))
         (unless (symbolp name)
           (loop-error "bad variable ~S somewhere in LOOP" name))
                (loop-error "duplicated variable ~S in LOOP parallel binding"
                            name)))
         (unless (symbolp name)
           (loop-error "bad variable ~S somewhere in LOOP" name))

-        (loop-declare-variable name dtype)
+        (loop-declare-var name dtype)

         ;; We use ASSOC on this list to check for duplications (above),
         ;; so don't optimize out this list:
         (push (list name (or initialization (loop-typed-init dtype)))
         ;; We use ASSOC on this list to check for duplications (above),
         ;; so don't optimize out this list:
         (push (list name (or initialization (loop-typed-init dtype)))

-              *loop-variables*))
+              *loop-vars*))

        (initialization
        (initialization

-        (cond (*loop-destructuring-hooks*
-               (loop-declare-variable name dtype)
-               (push (list name initialization) *loop-variables*))
-              (t (let ((newvar (gensym "LOOP-DESTRUCTURE-")))
-                   (push (list newvar initialization) *loop-variables*)
-                   ;; *LOOP-DESETQ-CROCKS* gathered in reverse order.
-                   (setq *loop-desetq-crocks*
-                     (list* name newvar *loop-desetq-crocks*))))))
+        (let ((newvar (gensym "LOOP-DESTRUCTURE-")))
+           (loop-declare-var name dtype)
+           (push (list newvar initialization) *loop-vars*)
+           ;; *LOOP-DESETQ-CROCKS* gathered in reverse order.
+           (setq *loop-desetq-crocks*
+                 (list* name newvar *loop-desetq-crocks*))))

        (t (let ((tcar nil) (tcdr nil))
             (if (atom dtype) (setq tcar (setq tcdr dtype))
                 (setq tcar (car dtype) tcdr (cdr dtype)))
        (t (let ((tcar nil) (tcdr nil))
             (if (atom dtype) (setq tcar (setq tcdr dtype))
                 (setq tcar (car dtype) tcdr (cdr dtype)))

-            (loop-make-variable (car name) nil tcar iteration-variable-p)
-            (loop-make-variable (cdr name) nil tcdr iteration-variable-p))))
+            (loop-make-var (car name) nil tcar iteration-var-p)
+            (loop-make-var (cdr name) nil tcdr iteration-var-p))))

   name)
 
   name)
 

-(defun loop-make-iteration-variable (name initialization dtype)
-  (loop-make-variable name initialization dtype t))
+(defun loop-make-iteration-var (name initialization dtype)
+  (loop-make-var name initialization dtype t))

 
 

-(defun loop-declare-variable (name dtype)
+(defun loop-declare-var (name dtype)

   (cond ((or (null name) (null dtype) (eq dtype t)) nil)
        ((symbolp name)
         (unless (sb!xc:subtypep t dtype)
   (cond ((or (null name) (null dtype) (eq dtype t)) nil)
        ((symbolp name)
         (unless (sb!xc:subtypep t dtype)

@@ -1041,19 +1074,22 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
             (push `(type ,dtype ,name) *loop-declarations*))))
        ((consp name)
         (cond ((consp dtype)
             (push `(type ,dtype ,name) *loop-declarations*))))
        ((consp name)
         (cond ((consp dtype)

-               (loop-declare-variable (car name) (car dtype))
-               (loop-declare-variable (cdr name) (cdr dtype)))
-              (t (loop-declare-variable (car name) dtype)
-                 (loop-declare-variable (cdr name) dtype))))
+               (loop-declare-var (car name) (car dtype))
+               (loop-declare-var (cdr name) (cdr dtype)))
+              (t (loop-declare-var (car name) dtype)
+                 (loop-declare-var (cdr name) dtype))))

        (t (error "invalid LOOP variable passed in: ~S" name))))
 
 (defun loop-maybe-bind-form (form data-type)
   (if (loop-constantp form)
       form
        (t (error "invalid LOOP variable passed in: ~S" name))))
 
 (defun loop-maybe-bind-form (form data-type)
   (if (loop-constantp form)
       form

-      (loop-make-variable (gensym "LOOP-BIND-") form data-type)))
+      (loop-make-var (gensym "LOOP-BIND-") form data-type)))

 \f
 (defun loop-do-if (for negatep)
 \f
 (defun loop-do-if (for negatep)

-  (let ((form (loop-get-form)) (*loop-inside-conditional* t) (it-p nil))
+  (let ((form (loop-get-form))
+       (*loop-inside-conditional* t)
+       (it-p nil)
+       (first-clause-p t))

     (flet ((get-clause (for)
             (do ((body nil)) (nil)
               (let ((key (car *loop-source-code*)) (*loop-body* nil) data)
     (flet ((get-clause (for)
             (do ((body nil)) (nil)
               (let ((key (car *loop-source-code*)) (*loop-body* nil) data)

@@ -1063,11 +1099,12 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                          key for))
                       (t (setq *loop-source-context* *loop-source-code*)
                          (loop-pop-source)
                          key for))
                       (t (setq *loop-source-context* *loop-source-code*)
                          (loop-pop-source)

-                         (when (loop-tequal (car *loop-source-code*) 'it)
+                         (when (and (loop-tequal (car *loop-source-code*) 'it)
+                                    first-clause-p)

                            (setq *loop-source-code*
                                  (cons (or it-p
                                            (setq it-p
                            (setq *loop-source-code*
                                  (cons (or it-p
                                            (setq it-p

-                                                 (loop-when-it-variable)))
+                                                 (loop-when-it-var)))

                                        (cdr *loop-source-code*))))
                          (cond ((or (not (setq data (loop-lookup-keyword
                                                       key (loop-universe-keywords *loop-universe*))))
                                        (cdr *loop-source-code*))))
                          (cond ((or (not (setq data (loop-lookup-keyword
                                                       key (loop-universe-keywords *loop-universe*))))

@@ -1078,6 +1115,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                                   "~S does not introduce a LOOP clause that can follow ~S."
                                   key for))
                                (t (setq body (nreconc *loop-body* body)))))))
                                   "~S does not introduce a LOOP clause that can follow ~S."
                                   key for))
                                (t (setq body (nreconc *loop-body* body)))))))

+              (setq first-clause-p nil)

               (if (loop-tequal (car *loop-source-code*) :and)
                   (loop-pop-source)
                   (return (if (cdr body)
               (if (loop-tequal (car *loop-source-code*) :and)
                   (loop-pop-source)
                   (return (if (cdr body)

@@ -1115,7 +1153,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
     (when *loop-names*
       (loop-error "You may only use one NAMED clause in your loop: NAMED ~S ... NAMED ~S."
                  (car *loop-names*) name))
     (when *loop-names*
       (loop-error "You may only use one NAMED clause in your loop: NAMED ~S ... NAMED ~S."
                  (car *loop-names*) name))

-    (setq *loop-names* (list name nil))))
+    (setq *loop-names* (list name))))

 
 (defun loop-do-return ()
   (loop-pseudo-body (loop-construct-return (loop-get-form))))
 
 (defun loop-do-return ()
   (loop-pseudo-body (loop-construct-return (loop-get-form))))

@@ -1140,11 +1178,15 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                (loop-pop-source))))
     (when (not (symbolp name))
       (loop-error "The value accumulation recipient name, ~S, is not a symbol." name))
                (loop-pop-source))))
     (when (not (symbolp name))
       (loop-error "The value accumulation recipient name, ~S, is not a symbol." name))

+    (unless name
+      (loop-disallow-aggregate-booleans))

     (unless dtype
       (setq dtype (or (loop-optional-type) default-type)))
     (let ((cruft (find (the symbol name) *loop-collection-cruft*
                       :key #'loop-collector-name)))
       (cond ((not cruft)
     (unless dtype
       (setq dtype (or (loop-optional-type) default-type)))
     (let ((cruft (find (the symbol name) *loop-collection-cruft*
                       :key #'loop-collector-name)))
       (cond ((not cruft)

+            (when (and name (loop-var-p name))
+              (loop-error "Variable ~S in INTO clause is a duplicate" name))

             (push (setq cruft (make-loop-collector
                                 :name name :class class
                                 :history (list collector) :dtype dtype))
             (push (setq cruft (make-loop-collector
                                 :name name :class class
                                 :history (list collector) :dtype dtype))

@@ -1194,7 +1236,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
     (let ((tempvars (loop-collector-tempvars lc)))
       (unless tempvars
        (setf (loop-collector-tempvars lc)
     (let ((tempvars (loop-collector-tempvars lc)))
       (unless tempvars
        (setf (loop-collector-tempvars lc)

-             (setq tempvars (list (loop-make-variable
+             (setq tempvars (list (loop-make-var

                                     (or (loop-collector-name lc)
                                         (gensym "LOOP-SUM-"))
                                     nil (loop-collector-dtype lc)))))
                                     (or (loop-collector-name lc)
                                         (gensym "LOOP-SUM-"))
                                     nil (loop-collector-dtype lc)))))

@@ -1236,6 +1278,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 (defun loop-do-always (restrictive negate)
   (let ((form (loop-get-form)))
     (when restrictive (loop-disallow-conditional))
 (defun loop-do-always (restrictive negate)
   (let ((form (loop-get-form)))
     (when restrictive (loop-disallow-conditional))

+    (loop-disallow-anonymous-collectors)

     (loop-emit-body `(,(if negate 'when 'unless) ,form
                      ,(loop-construct-return nil)))
     (loop-emit-final-value t)))
     (loop-emit-body `(,(if negate 'when 'unless) ,form
                      ,(loop-construct-return nil)))
     (loop-emit-final-value t)))

@@ -1245,13 +1288,31 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 ;;; Under ANSI this is not permitted to appear under conditionalization.
 (defun loop-do-thereis (restrictive)
   (when restrictive (loop-disallow-conditional))
 ;;; Under ANSI this is not permitted to appear under conditionalization.
 (defun loop-do-thereis (restrictive)
   (when restrictive (loop-disallow-conditional))

-  (loop-emit-body `(when (setq ,(loop-when-it-variable) ,(loop-get-form))
-                    ,(loop-construct-return *loop-when-it-variable*))))
+  (loop-disallow-anonymous-collectors)
+  (loop-emit-final-value)
+  (loop-emit-body `(when (setq ,(loop-when-it-var) ,(loop-get-form))
+                   ,(loop-construct-return *loop-when-it-var*))))

 \f
 (defun loop-do-while (negate kwd &aux (form (loop-get-form)))
   (loop-disallow-conditional kwd)
   (loop-pseudo-body `(,(if negate 'when 'unless) ,form (go end-loop))))
 
 \f
 (defun loop-do-while (negate kwd &aux (form (loop-get-form)))
   (loop-disallow-conditional kwd)
   (loop-pseudo-body `(,(if negate 'when 'unless) ,form (go end-loop))))
 

+(defun loop-do-repeat ()
+  (loop-disallow-conditional :repeat)
+  (let ((form (loop-get-form))
+       (type 'integer))
+    (let ((var (loop-make-var (gensym "LOOP-REPEAT-") `(ceiling ,form) type)))
+      (push `(if (<= ,var 0) (go end-loop) (decf ,var)) *loop-before-loop*)
+      (push `(if (<= ,var 0) (go end-loop) (decf ,var)) *loop-after-body*)
+      ;; FIXME: What should
+      ;;   (loop count t into a
+      ;;         repeat 3
+      ;;         count t into b
+      ;;         finally (return (list a b)))
+      ;; return: (3 3) or (4 3)? PUSHes above are for the former
+      ;; variant, L-P-B below for the latter.
+      #+nil (loop-pseudo-body `(when (minusp (decf ,var)) (go end-loop))))))
+

 (defun loop-do-with ()
   (loop-disallow-conditional :with)
   (do ((var) (val) (dtype)) (nil)
 (defun loop-do-with ()
   (loop-disallow-conditional :with)
   (do ((var) (val) (dtype)) (nil)

@@ -1261,7 +1322,9 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                     (loop-pop-source)
                     (loop-get-form))
                    (t nil)))
                     (loop-pop-source)
                     (loop-get-form))
                    (t nil)))

-    (loop-make-variable var val dtype)
+    (when (and var (loop-var-p var))
+      (loop-error "Variable ~S has already been used" var))
+    (loop-make-var var val dtype)

     (if (loop-tequal (car *loop-source-code*) :and)
        (loop-pop-source)
        (return (loop-bind-block)))))
     (if (loop-tequal (car *loop-source-code*) :and)
        (loop-pop-source)
        (return (loop-bind-block)))))

@@ -1353,30 +1416,10 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                  keyword))
     (apply (car tem) var first-arg data-type (cdr tem))))
 
                  keyword))
     (apply (car tem) var first-arg data-type (cdr tem))))
 

-(defun loop-do-repeat ()
-  (let ((form (loop-get-form))
-       (type (loop-check-data-type (loop-optional-type)
-                                   'real)))
-    (when (and (consp form)
-              (eq (car form) 'the)
-              (sb!xc:subtypep (second form) type))
-      (setq type (second form)))
-    (multiple-value-bind (number constantp value)
-       (loop-constant-fold-if-possible form type)
-      (cond ((and constantp (<= value 1)) `(t () () () ,(<= value 0) () () ()))
-           (t (let ((var (loop-make-variable (gensym "LOOP-REPEAT-")
-                                             number
-                                             type)))
-                (if constantp
-                    `((not (plusp (setq ,var (1- ,var))))
-                      () () () () () () ())
-                    `((minusp (setq ,var (1- ,var)))
-                      () () ()))))))))
-
-(defun loop-when-it-variable ()
-  (or *loop-when-it-variable*
-      (setq *loop-when-it-variable*
-           (loop-make-variable (gensym "LOOP-IT-") nil nil))))
+(defun loop-when-it-var ()
+  (or *loop-when-it-var*
+      (setq *loop-when-it-var*
+           (loop-make-var (gensym "LOOP-IT-") nil nil))))

 \f
 ;;;; various FOR/AS subdispatches
 
 \f
 ;;;; various FOR/AS subdispatches
 

@@ -1386,7 +1429,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 ;;; is present. I.e., the first initialization occurs in the loop body
 ;;; (first-step), not in the variable binding phase.
 (defun loop-ansi-for-equals (var val data-type)
 ;;; is present. I.e., the first initialization occurs in the loop body
 ;;; (first-step), not in the variable binding phase.
 (defun loop-ansi-for-equals (var val data-type)

-  (loop-make-iteration-variable var nil data-type)
+  (loop-make-iteration-var var nil data-type)

   (cond ((loop-tequal (car *loop-source-code*) :then)
         ;; Then we are the same as "FOR x FIRST y THEN z".
         (loop-pop-source)
   (cond ((loop-tequal (car *loop-source-code*) :then)
         ;; Then we are the same as "FOR x FIRST y THEN z".
         (loop-pop-source)

@@ -1396,23 +1439,23 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
         `(() (,var ,val) () ()))))
 
 (defun loop-for-across (var val data-type)
         `(() (,var ,val) () ()))))
 
 (defun loop-for-across (var val data-type)

-  (loop-make-iteration-variable var nil data-type)
+  (loop-make-iteration-var var nil data-type)

   (let ((vector-var (gensym "LOOP-ACROSS-VECTOR-"))
        (index-var (gensym "LOOP-ACROSS-INDEX-")))
     (multiple-value-bind (vector-form constantp vector-value)
        (loop-constant-fold-if-possible val 'vector)
   (let ((vector-var (gensym "LOOP-ACROSS-VECTOR-"))
        (index-var (gensym "LOOP-ACROSS-INDEX-")))
     (multiple-value-bind (vector-form constantp vector-value)
        (loop-constant-fold-if-possible val 'vector)

-      (loop-make-variable
+      (loop-make-var

        vector-var vector-form
        (if (and (consp vector-form) (eq (car vector-form) 'the))
            (cadr vector-form)
            'vector))
        vector-var vector-form
        (if (and (consp vector-form) (eq (car vector-form) 'the))
            (cadr vector-form)
            'vector))

-      (loop-make-variable index-var 0 'fixnum)
+      (loop-make-var index-var 0 'fixnum)

       (let* ((length 0)
             (length-form (cond ((not constantp)
                                 (let ((v (gensym "LOOP-ACROSS-LIMIT-")))
                                   (push `(setq ,v (length ,vector-var))
                                         *loop-prologue*)
       (let* ((length 0)
             (length-form (cond ((not constantp)
                                 (let ((v (gensym "LOOP-ACROSS-LIMIT-")))
                                   (push `(setq ,v (length ,vector-var))
                                         *loop-prologue*)

-                                  (loop-make-variable v 0 'fixnum)))
+                                  (loop-make-var v 0 'fixnum)))

                                (t (setq length (length vector-value)))))
             (first-test `(>= ,index-var ,length-form))
             (other-test first-test)
                                (t (setq length (length vector-value)))))
             (first-test `(>= ,index-var ,length-form))
             (other-test first-test)

@@ -1447,9 +1490,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
          ((and (consp stepper) (eq (car stepper) 'function))
           (list (cadr stepper) listvar))
          (t
          ((and (consp stepper) (eq (car stepper) 'function))
           (list (cadr stepper) listvar))
          (t

-          `(funcall ,(loop-make-variable (gensym "LOOP-FN-")
-                                         stepper
-                                         'function)
+          `(funcall ,(loop-make-var (gensym "LOOP-FN-") stepper 'function)

                     ,listvar)))))
 
 (defun loop-for-on (var val data-type)
                     ,listvar)))))
 
 (defun loop-for-on (var val data-type)

@@ -1457,9 +1498,9 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
       (loop-constant-fold-if-possible val)
     (let ((listvar var))
       (cond ((and var (symbolp var))
       (loop-constant-fold-if-possible val)
     (let ((listvar var))
       (cond ((and var (symbolp var))

-            (loop-make-iteration-variable var list data-type))
-           (t (loop-make-variable (setq listvar (gensym)) list 'list)
-              (loop-make-iteration-variable var nil data-type)))
+            (loop-make-iteration-var var list data-type))
+           (t (loop-make-var (setq listvar (gensym)) list 'list)
+              (loop-make-iteration-var var nil data-type)))

       (let ((list-step (loop-list-step listvar)))
        (let* ((first-endtest
                ;; mysterious comment from original CMU CL sources:
       (let ((list-step (loop-list-step listvar)))
        (let* ((first-endtest
                ;; mysterious comment from original CMU CL sources:

@@ -1484,8 +1525,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
   (multiple-value-bind (list constantp list-value)
       (loop-constant-fold-if-possible val)
     (let ((listvar (gensym "LOOP-LIST-")))
   (multiple-value-bind (list constantp list-value)
       (loop-constant-fold-if-possible val)
     (let ((listvar (gensym "LOOP-LIST-")))

-      (loop-make-iteration-variable var nil data-type)
-      (loop-make-variable listvar list 'list)
+      (loop-make-iteration-var var nil data-type)
+      (loop-make-var listvar list 'list)

       (let ((list-step (loop-list-step listvar)))
        (let* ((first-endtest `(endp ,listvar))
               (other-endtest first-endtest)
       (let ((list-step (loop-list-step listvar)))
        (let* ((first-endtest `(endp ,listvar))
               (other-endtest first-endtest)

@@ -1526,7 +1567,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
       (setf (gethash (symbol-name name) ht) lp))
     lp))
 \f
       (setf (gethash (symbol-name name) ht) lp))
     lp))
 \f

-;;; Note:  path functions are allowed to use loop-make-variable, hack
+;;; Note: Path functions are allowed to use LOOP-MAKE-VAR, hack

 ;;; the prologue, etc.
 (defun loop-for-being (var val data-type)
   ;; FOR var BEING each/the pathname prep-phrases using-stuff... each/the =
 ;;; the prologue, etc.
 (defun loop-for-being (var val data-type)
   ;; FOR var BEING each/the pathname prep-phrases using-stuff... each/the =

@@ -1566,8 +1607,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
       (setq stuff (if inclusive
                      (apply fun var data-type preps :inclusive t user-data)
                      (apply fun var data-type preps user-data))))
       (setq stuff (if inclusive
                      (apply fun var data-type preps :inclusive t user-data)
                      (apply fun var data-type preps user-data))))

-    (when *loop-named-variables*
-      (loop-error "Unused USING variables: ~S." *loop-named-variables*))
+    (when *loop-named-vars*
+      (loop-error "Unused USING vars: ~S." *loop-named-vars*))

     ;; STUFF is now (bindings prologue-forms . stuff-to-pass-back).
     ;; Protect the system from the user and the user from himself.
     (unless (member (length stuff) '(6 10))
     ;; STUFF is now (bindings prologue-forms . stuff-to-pass-back).
     ;; Protect the system from the user and the user from himself.
     (unless (member (length stuff) '(6 10))

@@ -1575,21 +1616,21 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                  path))
     (do ((l (car stuff) (cdr l)) (x)) ((null l))
       (if (atom (setq x (car l)))
                  path))
     (do ((l (car stuff) (cdr l)) (x)) ((null l))
       (if (atom (setq x (car l)))

-         (loop-make-iteration-variable x nil nil)
-         (loop-make-iteration-variable (car x) (cadr x) (caddr x))))
+         (loop-make-iteration-var x nil nil)
+         (loop-make-iteration-var (car x) (cadr x) (caddr x))))

     (setq *loop-prologue* (nconc (reverse (cadr stuff)) *loop-prologue*))
     (cddr stuff)))
 \f
     (setq *loop-prologue* (nconc (reverse (cadr stuff)) *loop-prologue*))
     (cddr stuff)))
 \f

-(defun named-variable (name)
-  (let ((tem (loop-tassoc name *loop-named-variables*)))
+(defun loop-named-var (name)
+  (let ((tem (loop-tassoc name *loop-named-vars*)))

     (declare (list tem))
     (cond ((null tem) (values (gensym) nil))
     (declare (list tem))
     (cond ((null tem) (values (gensym) nil))

-         (t (setq *loop-named-variables* (delete tem *loop-named-variables*))
+         (t (setq *loop-named-vars* (delete tem *loop-named-vars*))

             (values (cdr tem) t)))))
 
 (defun loop-collect-prepositional-phrases (preposition-groups
                                           &optional
             (values (cdr tem) t)))))
 
 (defun loop-collect-prepositional-phrases (preposition-groups
                                           &optional

-                                          USING-allowed
+                                          using-allowed

                                           initial-phrases)
   (flet ((in-group-p (x group) (car (loop-tmember x group))))
     (do ((token nil)
                                           initial-phrases)
   (flet ((in-group-p (x group) (car (loop-tmember x group))))
     (do ((token nil)

@@ -1597,9 +1638,9 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
         (this-group nil nil)
         (this-prep nil nil)
         (disallowed-prepositions
         (this-group nil nil)
         (this-prep nil nil)
         (disallowed-prepositions

-          (mapcan #'(lambda (x)
-                      (copy-list
-                        (find (car x) preposition-groups :test #'in-group-p)))
+          (mapcan (lambda (x)
+                    (copy-list
+                     (find (car x) preposition-groups :test #'in-group-p)))

                   initial-phrases))
         (used-prepositions (mapcar #'car initial-phrases)))
        ((null *loop-source-code*) (nreverse prepositional-phrases))
                   initial-phrases))
         (used-prepositions (mapcar #'car initial-phrases)))
        ((null *loop-source-code*) (nreverse prepositional-phrases))

@@ -1620,22 +1661,16 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                                         (cons this-group used-prepositions)))
             (loop-pop-source)
             (push (list this-prep (loop-get-form)) prepositional-phrases))
                                         (cons this-group used-prepositions)))
             (loop-pop-source)
             (push (list this-prep (loop-get-form)) prepositional-phrases))

-           ((and USING-allowed (loop-tequal token 'using))
+           ((and using-allowed (loop-tequal token 'using))

             (loop-pop-source)
             (do ((z (loop-pop-source) (loop-pop-source)) (tem)) (nil)
             (loop-pop-source)
             (do ((z (loop-pop-source) (loop-pop-source)) (tem)) (nil)

-              (when (or (atom z)
-                        (atom (cdr z))
-                        (not (null (cddr z)))
-                        (not (symbolp (car z)))
-                        (and (cadr z) (not (symbolp (cadr z)))))
-                (loop-error "~S bad variable pair in path USING phrase" z))

               (when (cadr z)
               (when (cadr z)

-                (if (setq tem (loop-tassoc (car z) *loop-named-variables*))
+                (if (setq tem (loop-tassoc (car z) *loop-named-vars*))

                     (loop-error
                       "The variable substitution for ~S occurs twice in a USING phrase,~@
                        with ~S and ~S."
                       (car z) (cadr z) (cadr tem))
                     (loop-error
                       "The variable substitution for ~S occurs twice in a USING phrase,~@
                        with ~S and ~S."
                       (car z) (cadr z) (cadr tem))

-                    (push (cons (car z) (cadr z)) *loop-named-variables*)))
+                    (push (cons (car z) (cadr z)) *loop-named-vars*)))

               (when (or (null *loop-source-code*)
                         (symbolp (car *loop-source-code*)))
                 (return nil))))
               (when (or (null *loop-source-code*)
                         (symbolp (car *loop-source-code*)))
                 (return nil))))

@@ -1648,7 +1683,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                       sequence-variable sequence-type
                       step-hack default-top
                       prep-phrases)
                       sequence-variable sequence-type
                       step-hack default-top
                       prep-phrases)

-   (let ((endform nil) ; Form (constant or variable) with limit value
+   (let ((endform nil) ; form (constant or variable) with limit value

         (sequencep nil) ; T if sequence arg has been provided
         (testfn nil) ; endtest function
         (test nil) ; endtest form
         (sequencep nil) ; T if sequence arg has been provided
         (testfn nil) ; endtest function
         (test nil) ; endtest form

@@ -1664,20 +1699,20 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
         (limit-constantp nil)
         (limit-value nil)
         )
         (limit-constantp nil)
         (limit-value nil)
         )

-     (when variable (loop-make-iteration-variable variable nil variable-type))
+     (when variable (loop-make-iteration-var variable nil variable-type))

      (do ((l prep-phrases (cdr l)) (prep) (form) (odir)) ((null l))
        (setq prep (caar l) form (cadar l))
        (case prep
         ((:of :in)
          (setq sequencep t)
      (do ((l prep-phrases (cdr l)) (prep) (form) (odir)) ((null l))
        (setq prep (caar l) form (cadar l))
        (case prep
         ((:of :in)
          (setq sequencep t)

-         (loop-make-variable sequence-variable form sequence-type))
+         (loop-make-var sequence-variable form sequence-type))

         ((:from :downfrom :upfrom)
          (setq start-given t)
          (cond ((eq prep :downfrom) (setq dir ':down))
                ((eq prep :upfrom) (setq dir ':up)))
          (multiple-value-setq (form start-constantp start-value)
            (loop-constant-fold-if-possible form indexv-type))
         ((:from :downfrom :upfrom)
          (setq start-given t)
          (cond ((eq prep :downfrom) (setq dir ':down))
                ((eq prep :upfrom) (setq dir ':up)))
          (multiple-value-setq (form start-constantp start-value)
            (loop-constant-fold-if-possible form indexv-type))

-         (loop-make-iteration-variable indexv form indexv-type))
+         (loop-make-iteration-var indexv form indexv-type))

         ((:upto :to :downto :above :below)
          (cond ((loop-tequal prep :upto) (setq inclusive-iteration
                                                (setq dir ':up)))
         ((:upto :to :downto :above :below)
          (cond ((loop-tequal prep :upto) (setq inclusive-iteration
                                                (setq dir ':up)))

@@ -1688,21 +1723,22 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                ((loop-tequal prep :below) (setq dir ':up)))
          (setq limit-given t)
          (multiple-value-setq (form limit-constantp limit-value)
                ((loop-tequal prep :below) (setq dir ':up)))
          (setq limit-given t)
          (multiple-value-setq (form limit-constantp limit-value)

-           (loop-constant-fold-if-possible form indexv-type))
+           (loop-constant-fold-if-possible form `(and ,indexv-type real)))

          (setq endform (if limit-constantp
                            `',limit-value
          (setq endform (if limit-constantp
                            `',limit-value

-                           (loop-make-variable
-                             (gensym "LOOP-LIMIT-") form indexv-type))))
+                           (loop-make-var
+                            (gensym "LOOP-LIMIT-") form
+                             `(and ,indexv-type real)))))

         (:by
         (:by

-          (multiple-value-setq (form stepby-constantp stepby)
-            (loop-constant-fold-if-possible form indexv-type))
-          (unless stepby-constantp
-            (loop-make-variable (setq stepby (gensym "LOOP-STEP-BY-"))
-                                form
-                                indexv-type)))
+         (multiple-value-setq (form stepby-constantp stepby)
+           (loop-constant-fold-if-possible form `(and ,indexv-type (real (0)))))
+         (unless stepby-constantp
+           (loop-make-var (setq stepby (gensym "LOOP-STEP-BY-"))
+                          form
+                          `(and ,indexv-type (real (0))))))

         (t (loop-error
         (t (loop-error

-             "~S invalid preposition in sequencing or sequence path;~@
-              maybe invalid prepositions were specified in iteration path descriptor?"
+            "~S invalid preposition in sequencing or sequence path;~@
+             maybe invalid prepositions were specified in iteration path descriptor?"

              prep)))
        (when (and odir dir (not (eq dir odir)))
         (loop-error "conflicting stepping directions in LOOP sequencing path"))
              prep)))
        (when (and odir dir (not (eq dir odir)))
         (loop-error "conflicting stepping directions in LOOP sequencing path"))

@@ -1710,18 +1746,33 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
      (when (and sequence-variable (not sequencep))
        (loop-error "missing OF or IN phrase in sequence path"))
      ;; Now fill in the defaults.
      (when (and sequence-variable (not sequencep))
        (loop-error "missing OF or IN phrase in sequence path"))
      ;; Now fill in the defaults.

-     (unless start-given
-       (loop-make-iteration-variable
-        indexv
-        (setq start-constantp t
-              start-value (or (loop-typed-init indexv-type) 0))
-        indexv-type))
+     (if start-given
+        (when limit-given
+          ;; if both start and limit are given, they had better both
+          ;; be REAL.  We already enforce the REALness of LIMIT,
+          ;; above; here's the KLUDGE to enforce the type of START.
+          (flet ((type-declaration-of (x)
+                   (and (eq (car x) 'type) (caddr x))))
+            (let ((decl (find indexv *loop-declarations*
+                              :key #'type-declaration-of))
+                  (%decl (find indexv *loop-declarations*
+                               :key #'type-declaration-of
+                               :from-end t)))
+              (sb!int:aver (eq decl %decl))
+              (setf (cadr decl)
+                    `(and real ,(cadr decl))))))
+        ;; default start
+        (loop-make-iteration-var
+         indexv
+         (setq start-constantp t
+               start-value (or (loop-typed-init indexv-type) 0))
+         `(and ,indexv-type real)))

      (cond ((member dir '(nil :up))
            (when (or limit-given default-top)
              (unless limit-given
      (cond ((member dir '(nil :up))
            (when (or limit-given default-top)
              (unless limit-given

-               (loop-make-variable (setq endform
-                                         (gensym "LOOP-SEQ-LIMIT-"))
-                                   nil indexv-type)
+               (loop-make-var (setq endform (gensym "LOOP-SEQ-LIMIT-"))
+                              nil
+                              indexv-type)

                (push `(setq ,endform ,default-top) *loop-prologue*))
              (setq testfn (if inclusive-iteration '> '>=)))
            (setq step (if (eql stepby 1) `(1+ ,indexv) `(+ ,indexv ,stepby))))
                (push `(setq ,endform ,default-top) *loop-prologue*))
              (setq testfn (if inclusive-iteration '> '>=)))
            (setq step (if (eql stepby 1) `(1+ ,indexv) `(+ ,indexv ,stepby))))

@@ -1742,7 +1793,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
        (setq step-hack
             `(,variable ,step-hack)))
      (let ((first-test test) (remaining-tests test))
        (setq step-hack
             `(,variable ,step-hack)))
      (let ((first-test test) (remaining-tests test))

-       (when (and stepby-constantp start-constantp limit-constantp)
+       (when (and stepby-constantp start-constantp limit-constantp
+                 (realp start-value) (realp limit-value))

         (when (setq first-test
                     (funcall (symbol-function testfn)
                              start-value
         (when (setq first-test
                     (funcall (symbol-function testfn)
                              start-value

@@ -1755,7 +1807,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 
 (defun loop-for-arithmetic (var val data-type kwd)
   (loop-sequencer
 
 (defun loop-for-arithmetic (var val data-type kwd)
   (loop-sequencer

-   var (loop-check-data-type data-type 'real)
+   var (loop-check-data-type data-type 'number)

    nil nil nil nil nil nil
    (loop-collect-prepositional-phrases
     '((:from :upfrom :downfrom) (:to :upto :downto :above :below) (:by))
    nil nil nil nil nil nil
    (loop-collect-prepositional-phrases
     '((:from :upfrom :downfrom) (:to :upto :downto :above :below) (:by))

@@ -1767,8 +1819,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                                    size-function
                                    sequence-type
                                    element-type)
                                    size-function
                                    sequence-type
                                    element-type)

-  (multiple-value-bind (indexv) (named-variable 'index)
-    (let ((sequencev (named-variable 'sequence)))
+  (multiple-value-bind (indexv) (loop-named-var 'index)
+    (let ((sequencev (loop-named-var 'sequence)))

       (list* nil nil                           ; dummy bindings and prologue
             (loop-sequencer
              indexv 'fixnum 
       (list* nil nil                           ; dummy bindings and prologue
             (loop-sequencer
              indexv 'fixnum 

@@ -1788,7 +1840,7 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 ||#
 
 (defun loop-hash-table-iteration-path (variable data-type prep-phrases
 ||#
 
 (defun loop-hash-table-iteration-path (variable data-type prep-phrases

-                                      &key (which (required-argument)))
+                                      &key (which (sb!int:missing-arg)))

   (declare (type (member :hash-key :hash-value) which))
   (cond ((or (cdr prep-phrases) (not (member (caar prep-phrases) '(:in :of))))
         (loop-error "too many prepositions!"))
   (declare (type (member :hash-key :hash-value) which))
   (cond ((or (cdr prep-phrases) (not (member (caar prep-phrases) '(:in :of))))
         (loop-error "too many prepositions!"))

@@ -1799,62 +1851,65 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
        (dummy-predicate-var nil)
        (post-steps nil))
     (multiple-value-bind (other-var other-p)
        (dummy-predicate-var nil)
        (post-steps nil))
     (multiple-value-bind (other-var other-p)

-       (named-variable (ecase which
+       (loop-named-var (ecase which

                          (:hash-key 'hash-value)
                          (:hash-value 'hash-key)))
                          (:hash-key 'hash-value)
                          (:hash-value 'hash-key)))

-      ;; @@@@ NAMED-VARIABLE returns a second value of T if the name
+      ;; @@@@ LOOP-NAMED-VAR returns a second value of T if the name

       ;; was actually specified, so clever code can throw away the
       ;; GENSYM'ed-up variable if it isn't really needed. The
       ;; following is for those implementations in which we cannot put
       ;; dummy NILs into MULTIPLE-VALUE-SETQ variable lists.
       (setq other-p t
       ;; was actually specified, so clever code can throw away the
       ;; GENSYM'ed-up variable if it isn't really needed. The
       ;; following is for those implementations in which we cannot put
       ;; dummy NILs into MULTIPLE-VALUE-SETQ variable lists.
       (setq other-p t

-           dummy-predicate-var (loop-when-it-variable))
-      (let ((key-var nil)
-           (val-var nil)
-           (bindings `((,variable nil ,data-type)
-                       (,ht-var ,(cadar prep-phrases))
-                       ,@(and other-p other-var `((,other-var nil))))))
+           dummy-predicate-var (loop-when-it-var))
+      (let* ((key-var nil)
+            (val-var nil)
+            (variable (or variable (gensym "LOOP-HASH-VAR-TEMP-")))
+            (bindings `((,variable nil ,data-type)
+                        (,ht-var ,(cadar prep-phrases))
+                        ,@(and other-p other-var `((,other-var nil))))))

        (ecase which
          (:hash-key (setq key-var variable
                           val-var (and other-p other-var)))
          (:hash-value (setq key-var (and other-p other-var)
                             val-var variable)))
        (push `(with-hash-table-iterator (,next-fn ,ht-var)) *loop-wrappers*)
        (ecase which
          (:hash-key (setq key-var variable
                           val-var (and other-p other-var)))
          (:hash-value (setq key-var (and other-p other-var)
                             val-var variable)))
        (push `(with-hash-table-iterator (,next-fn ,ht-var)) *loop-wrappers*)

-       (when (consp key-var)
-         (setq post-steps
-               `(,key-var ,(setq key-var (gensym "LOOP-HASH-KEY-TEMP-"))
-                          ,@post-steps))
-         (push `(,key-var nil) bindings))
-       (when (consp val-var)
-         (setq post-steps
-               `(,val-var ,(setq val-var (gensym "LOOP-HASH-VAL-TEMP-"))
-                          ,@post-steps))
-         (push `(,val-var nil) bindings))
-       `(,bindings                             ;bindings
-         ()                                    ;prologue
-         ()                                    ;pre-test
-         ()                                    ;parallel steps
+        (when (or (consp key-var) data-type)
+          (setq post-steps
+                `(,key-var ,(setq key-var (gensym "LOOP-HASH-KEY-TEMP-"))
+                           ,@post-steps))
+          (push `(,key-var nil) bindings))
+        (when (or (consp val-var) data-type)
+          (setq post-steps
+                `(,val-var ,(setq val-var (gensym "LOOP-HASH-VAL-TEMP-"))
+                           ,@post-steps))
+          (push `(,val-var nil) bindings))
+       `(,bindings                     ;bindings
+         ()                            ;prologue
+         ()                            ;pre-test
+         ()                            ;parallel steps

          (not (multiple-value-setq (,dummy-predicate-var ,key-var ,val-var)
          (not (multiple-value-setq (,dummy-predicate-var ,key-var ,val-var)

-                (,next-fn)))   ;post-test
+                (,next-fn)))           ;post-test

          ,post-steps)))))
 
 (defun loop-package-symbols-iteration-path (variable data-type prep-phrases
                                            &key symbol-types)
          ,post-steps)))))
 
 (defun loop-package-symbols-iteration-path (variable data-type prep-phrases
                                            &key symbol-types)

-  (cond ((or (cdr prep-phrases) (not (member (caar prep-phrases) '(:in :of))))
+  (cond ((and prep-phrases (cdr prep-phrases))

         (loop-error "Too many prepositions!"))
         (loop-error "Too many prepositions!"))

-       ((null prep-phrases)
-        (loop-error "missing OF or IN in ~S iteration path")))
+        ((and prep-phrases (not (member (caar prep-phrases) '(:in :of))))
+         (sb!int:bug "Unknown preposition ~S." (caar prep-phrases))))

   (unless (symbolp variable)
     (loop-error "Destructuring is not valid for package symbol iteration."))
   (let ((pkg-var (gensym "LOOP-PKGSYM-"))
   (unless (symbolp variable)
     (loop-error "Destructuring is not valid for package symbol iteration."))
   (let ((pkg-var (gensym "LOOP-PKGSYM-"))

-       (next-fn (gensym "LOOP-PKGSYM-NEXT-")))
+       (next-fn (gensym "LOOP-PKGSYM-NEXT-"))
+       (variable (or variable (gensym "LOOP-PKGSYM-VAR-")))
+        (package (or (cadar prep-phrases) '*package*)))

     (push `(with-package-iterator (,next-fn ,pkg-var ,@symbol-types))
          *loop-wrappers*)
     (push `(with-package-iterator (,next-fn ,pkg-var ,@symbol-types))
          *loop-wrappers*)

-    `(((,variable nil ,data-type) (,pkg-var ,(cadar prep-phrases)))
+    `(((,variable nil ,data-type) (,pkg-var ,package))

       ()
       ()
       ()
       ()
       ()
       ()

-      (not (multiple-value-setq (,(loop-when-it-variable)
+      (not (multiple-value-setq (,(loop-when-it-var)

                                 ,variable)
             (,next-fn)))
       ())))
                                 ,variable)
             (,next-fn)))
       ())))

@@ -1895,7 +1950,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                         (when (loop-do-if when nil))   ; Normal, do when
                         (if (loop-do-if if nil))       ; synonymous
                         (unless (loop-do-if unless t)) ; Negate test on when
                         (when (loop-do-if when nil))   ; Normal, do when
                         (if (loop-do-if if nil))       ; synonymous
                         (unless (loop-do-if unless t)) ; Negate test on when

-                        (with (loop-do-with)))
+                        (with (loop-do-with))
+                         (repeat (loop-do-repeat)))

             :for-keywords '((= (loop-ansi-for-equals))
                             (across (loop-for-across))
                             (in (loop-for-in))
             :for-keywords '((= (loop-ansi-for-equals))
                             (across (loop-for-across))
                             (in (loop-for-in))

@@ -1904,12 +1960,14 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                             (downfrom (loop-for-arithmetic :downfrom))
                             (upfrom (loop-for-arithmetic :upfrom))
                             (below (loop-for-arithmetic :below))
                             (downfrom (loop-for-arithmetic :downfrom))
                             (upfrom (loop-for-arithmetic :upfrom))
                             (below (loop-for-arithmetic :below))

+                             (above (loop-for-arithmetic :above))

                             (to (loop-for-arithmetic :to))
                             (upto (loop-for-arithmetic :upto))
                             (to (loop-for-arithmetic :to))
                             (upto (loop-for-arithmetic :upto))

+                            (downto (loop-for-arithmetic :downto))
+                            (by (loop-for-arithmetic :by))

                             (being (loop-for-being)))
             :iteration-keywords '((for (loop-do-for))
                             (being (loop-for-being)))
             :iteration-keywords '((for (loop-do-for))

-                                  (as (loop-do-for))
-                                  (repeat (loop-do-repeat)))
+                                  (as (loop-do-for)))

             :type-symbols '(array atom bignum bit bit-vector character
                             compiled-function complex cons double-float
                             fixnum float function hash-table integer
             :type-symbols '(array atom bignum bit bit-vector character
                             compiled-function complex cons double-float
                             fixnum float function hash-table integer

@@ -1944,7 +2002,8 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
                   'loop-package-symbols-iteration-path w
                   :preposition-groups '((:of :in))
                   :inclusive-permitted nil
                   'loop-package-symbols-iteration-path w
                   :preposition-groups '((:of :in))
                   :inclusive-permitted nil

-                  :user-data '(:symbol-types (:internal)))
+                  :user-data '(:symbol-types (:internal
+                                              :external)))

     w))
 
 (defparameter *loop-ansi-universe*
     w))
 
 (defparameter *loop-ansi-universe*

@@ -1952,9 +2011,9 @@ a LET-like macro, and a SETQ-like macro, which perform LOOP-style destructuring.
 
 (defun loop-standard-expansion (keywords-and-forms environment universe)
   (if (and keywords-and-forms (symbolp (car keywords-and-forms)))
 
 (defun loop-standard-expansion (keywords-and-forms environment universe)
   (if (and keywords-and-forms (symbolp (car keywords-and-forms)))

-    (loop-translate keywords-and-forms environment universe)
-    (let ((tag (gensym)))
-      `(block nil (tagbody ,tag (progn ,@keywords-and-forms) (go ,tag))))))
+      (loop-translate keywords-and-forms environment universe)
+      (let ((tag (gensym)))
+       `(block nil (tagbody ,tag (progn ,@keywords-and-forms) (go ,tag))))))

 
 (sb!int:defmacro-mundanely loop (&environment env &rest keywords-and-forms)
   (loop-standard-expansion keywords-and-forms env *loop-ansi-universe*))
 
 (sb!int:defmacro-mundanely loop (&environment env &rest keywords-and-forms)
   (loop-standard-expansion keywords-and-forms env *loop-ansi-universe*))