0.9.0.38:

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

diff --git a/src/code/loop.lisp b/src/code/loop.lisp
index 1f86e9f..3d9a363 100644 (file)
--- a/src/code/loop.lisp
+++ b/src/code/loop.lisp
@@ -426,10 +426,11 @@ code to be loaded.
 ;;; See LOOP-NAMED-VAR.
 (defvar *loop-named-vars*)
 
 ;;; 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 current group of bindings.

 (defvar *loop-vars*)
 
 (defvar *loop-vars*)
 

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

@@ -438,22 +439,18 @@ code to be loaded.
 
 ;;; list of wrapping forms, innermost first, which go immediately
 ;;; inside the current set of parallel bindings being accumulated in
 
 ;;; list of wrapping forms, innermost first, which go immediately
 ;;; inside the current set of parallel bindings being accumulated in

-;;; *LOOP-VARS*. The wrappers are appended onto a body. E.g.,
-;;; this list could conceivably have as its value
+;;; *LOOP-VARS*. The wrappers are appended onto a body. E.g., this
+;;; list could conceivably have as its value

 ;;;   ((WITH-OPEN-FILE (G0001 G0002 ...))),
 ;;;   ((WITH-OPEN-FILE (G0001 G0002 ...))),

-;;; with G0002 being one of the bindings in *LOOP-VARS* (This is
-;;; why the wrappers go inside of the variable bindings).
+;;; with G0002 being one of the bindings in *LOOP-VARS* (This is why
+;;; the wrappers go inside of the variable bindings).

 (defvar *loop-wrappers*)
 
 (defvar *loop-wrappers*)
 

-;;; This accumulates lists of previous values of *LOOP-VARS* and
-;;; the other lists above, for each new nesting of bindings. See
+;;; 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*)
 
 ;;; LOOP-BIND-BLOCK.
 (defvar *loop-bind-stack*)
 

-;;; This is simply a list of LOOP iteration variables, used for
-;;; checking for duplications.
-(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*)
 

@@ -479,8 +476,8 @@ code to be loaded.
 (defvar *loop-after-epilogue*)
 
 ;;; the "culprit" responsible for supplying a final value from the
 (defvar *loop-after-epilogue*)
 
 ;;; the "culprit" responsible for supplying a final value from the

-;;; loop. This is so LOOP-EMIT-FINAL-VALUE can moan about multiple
-;;; return values being supplied.
+;;; loop. This is so LOOP-DISALLOW-AGGREGATE-BOOLEANS can moan about
+;;; disallowed anonymous collections.

 (defvar *loop-final-value-culprit*)
 
 ;;; If this is true, we are in some branch of a conditional. Some
 (defvar *loop-final-value-culprit*)
 
 ;;; If this is true, we are in some branch of a conditional. Some

@@ -511,7 +508,8 @@ code to be loaded.
       (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)))

@@ -534,6 +532,11 @@ code to be loaded.
        ;; 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))))

@@ -787,7 +790,6 @@ code to be loaded.
                       *loop-universe*)
   (let ((*loop-original-source-code* *loop-source-code*)
        (*loop-source-context* nil)
                       *loop-universe*)
   (let ((*loop-original-source-code* *loop-source-code*)
        (*loop-source-context* nil)

-       (*loop-iteration-vars* nil)

        (*loop-vars* nil)
        (*loop-named-vars* nil)
        (*loop-declarations* nil)
        (*loop-vars* nil)
        (*loop-named-vars* nil)
        (*loop-declarations* nil)

@@ -837,7 +839,8 @@ code to be loaded.
       answer)))
 
 (defun loop-iteration-driver ()
       answer)))
 
 (defun loop-iteration-driver ()

-  (do () ((null *loop-source-code*))
+  (do () 
+      ((null *loop-source-code*))

     (let ((keyword (car *loop-source-code*)) (tem nil))
       (cond ((not (symbolp keyword))
             (loop-error "~S found where LOOP keyword expected" keyword))
     (let ((keyword (car *loop-source-code*)) (tem nil))
       (cond ((not (symbolp keyword))
             (loop-error "~S found where LOOP keyword expected" keyword))

@@ -902,10 +905,6 @@ code to be loaded.
 (defun loop-emit-final-value (&optional (form nil form-supplied-p))
   (when form-supplied-p
     (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*
-    (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)
   (setq *loop-final-value-culprit* (car *loop-source-context*)))
 
 (defun loop-disallow-conditional (&optional kwd)

@@ -922,12 +921,12 @@ code to be loaded.
 \f
 ;;;; loop types
 
 \f
 ;;;; loop types
 

-(defun loop-typed-init (data-type)
+(defun loop-typed-init (data-type &optional step-var-p)

   (when (and data-type (sb!xc:subtypep data-type 'number))
     (if (or (sb!xc:subtypep data-type 'float)
            (sb!xc:subtypep data-type '(complex float)))
   (when (and data-type (sb!xc:subtypep data-type 'number))
     (if (or (sb!xc:subtypep data-type 'float)
            (sb!xc:subtypep data-type '(complex float)))

-       (coerce 0 data-type)
-       0)))
+       (coerce (if step-var-p 1 0) data-type)
+       (if step-var-p 1 0))))

 
 (defun loop-optional-type (&optional variable)
   ;; No variable specified implies that no destructuring is permissible.
 
 (defun loop-optional-type (&optional variable)
   ;; No variable specified implies that no destructuring is permissible.

@@ -1018,27 +1017,23 @@ code to be loaded.
       ((null entry) (return nil))
       ((assoc name (caar entry) :test #'eq) (return t)))))
 
       ((null entry) (return nil))
       ((assoc name (caar entry) :test #'eq) (return t)))))
 

-(defun loop-make-var (name initialization dtype &optional iteration-var-p)
+(defun loop-make-var (name initialization dtype &optional step-var-p)

   (cond ((null name)
   (cond ((null name)

-        (cond ((not (null initialization))
-               (push (list (setq name (gensym "LOOP-IGNORE-"))
-                           initialization)
-                     *loop-vars*)
-               (push `(ignore ,name) *loop-declarations*))))
+        (setq name (gensym "LOOP-IGNORE-"))
+        (push (list name initialization) *loop-vars*)
+        (if (null initialization)
+            (push `(ignore ,name) *loop-declarations*)
+            (loop-declare-var name dtype)))

        ((atom name)
        ((atom name)

-        (cond (iteration-var-p
-               (if (member name *loop-iteration-vars*)
-                   (loop-error "duplicated LOOP iteration variable ~S" name)
-                   (push name *loop-iteration-vars*)))
-              ((assoc name *loop-vars*)
-               (loop-error "duplicated variable ~S in LOOP parallel binding"
-                           name)))
+         (when (or (assoc name *loop-vars*)
+                   (loop-var-p name))
+           (loop-error "duplicated variable ~S in a LOOP binding" name))

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

-        (loop-declare-var name dtype)
+        (loop-declare-var name dtype step-var-p)

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

               *loop-vars*))
        (initialization
         (let ((newvar (gensym "LOOP-DESTRUCTURE-")))
               *loop-vars*))
        (initialization
         (let ((newvar (gensym "LOOP-DESTRUCTURE-")))

@@ -1050,18 +1045,15 @@ code to be loaded.
        (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-var (car name) nil tcar iteration-var-p)
-            (loop-make-var (cdr name) nil tcdr iteration-var-p))))
+            (loop-make-var (car name) nil tcar)
+            (loop-make-var (cdr name) nil tcdr))))

   name)
 
   name)
 

-(defun loop-make-iteration-var (name initialization dtype)
-  (loop-make-var name initialization dtype t))
-
-(defun loop-declare-var (name dtype)
+(defun loop-declare-var (name dtype &optional step-var-p)

   (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)

-          (let ((dtype (let ((init (loop-typed-init dtype)))
+          (let ((dtype (let ((init (loop-typed-init dtype step-var-p)))

                          (if (sb!xc:typep init dtype)
                              dtype
                              `(or (member ,init) ,dtype)))))
                          (if (sb!xc:typep init dtype)
                              dtype
                              `(or (member ,init) ,dtype)))))

@@ -1150,7 +1142,7 @@ code to be loaded.
     (setq *loop-names* (list name))))
 
 (defun loop-do-return ()
     (setq *loop-names* (list name))))
 
 (defun loop-do-return ()

-  (loop-pseudo-body (loop-construct-return (loop-get-form))))
+  (loop-emit-body (loop-construct-return (loop-get-form))))

 \f
 ;;;; value accumulation: LIST
 
 \f
 ;;;; value accumulation: LIST
 

@@ -1188,12 +1180,12 @@ code to be loaded.
            (t (unless (eq (loop-collector-class cruft) class)
                 (loop-error
                   "incompatible kinds of LOOP value accumulation specified for collecting~@
            (t (unless (eq (loop-collector-class cruft) class)
                 (loop-error
                   "incompatible kinds of LOOP value accumulation specified for collecting~@

-                   ~:[as the value of the LOOP~;~:*INTO ~S~]: ~S and ~S"
+                    ~:[as the value of the LOOP~;~:*INTO ~S~]: ~S and ~S"

                   name (car (loop-collector-history cruft)) collector))
               (unless (equal dtype (loop-collector-dtype cruft))
                 (loop-warn
                   "unequal datatypes specified in different LOOP value accumulations~@
                   name (car (loop-collector-history cruft)) collector))
               (unless (equal dtype (loop-collector-dtype cruft))
                 (loop-warn
                   "unequal datatypes specified in different LOOP value accumulations~@

-                  into ~S: ~S and ~S"
+                   into ~S: ~S and ~S"

                   name dtype (loop-collector-dtype cruft))
                 (when (eq (loop-collector-dtype cruft) t)
                   (setf (loop-collector-dtype cruft) dtype)))
                   name dtype (loop-collector-dtype cruft))
                 (when (eq (loop-collector-dtype cruft) t)
                   (setf (loop-collector-dtype cruft) dtype)))

@@ -1309,7 +1301,8 @@ code to be loaded.
 
 (defun loop-do-with ()
   (loop-disallow-conditional :with)
 
 (defun loop-do-with ()
   (loop-disallow-conditional :with)

-  (do ((var) (val) (dtype)) (nil)
+  (do ((var) (val) (dtype)) 
+      (nil)

     (setq var (loop-pop-source)
          dtype (loop-optional-type var)
          val (cond ((loop-tequal (car *loop-source-code*) :=)
     (setq var (loop-pop-source)
          dtype (loop-optional-type var)
          val (cond ((loop-tequal (car *loop-source-code*) :=)

@@ -1423,7 +1416,7 @@ code to be loaded.
 ;;; 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-var var nil data-type)
+  (loop-make-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)

@@ -1433,7 +1426,7 @@ code to be loaded.
         `(() (,var ,val) () ()))))
 
 (defun loop-for-across (var val data-type)
         `(() (,var ,val) () ()))))
 
 (defun loop-for-across (var val data-type)

-  (loop-make-iteration-var var nil data-type)
+  (loop-make-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)
   (let ((vector-var (gensym "LOOP-ACROSS-VECTOR-"))
        (index-var (gensym "LOOP-ACROSS-INDEX-")))
     (multiple-value-bind (vector-form constantp vector-value)

@@ -1492,9 +1485,10 @@ code to be loaded.
       (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-var var list data-type))
-           (t (loop-make-var (setq listvar (gensym)) list 'list)
-              (loop-make-iteration-var var nil data-type)))
+            (loop-make-var var list data-type))
+           (t 
+             (loop-make-var (setq listvar (gensym)) list 't)
+             (loop-make-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:

@@ -1519,7 +1513,7 @@ code to be loaded.
   (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-var var nil data-type)
+      (loop-make-var var nil data-type)

       (loop-make-var listvar list 'list)
       (let ((list-step (loop-list-step listvar)))
        (let* ((first-endtest `(endp ,listvar))
       (loop-make-var listvar list 'list)
       (let ((list-step (loop-list-step listvar)))
        (let* ((first-endtest `(endp ,listvar))

@@ -1610,8 +1604,8 @@ code to be loaded.
                  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-var x nil nil)
-         (loop-make-iteration-var (car x) (cadr x) (caddr x))))
+         (loop-make-var x nil nil)
+         (loop-make-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

@@ -1662,7 +1656,7 @@ code to be loaded.
                 (if (setq tem (loop-tassoc (car z) *loop-named-vars*))
                     (loop-error
                       "The variable substitution for ~S occurs twice in a USING phrase,~@
                 (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."
+                        with ~S and ~S."

                       (car z) (cadr z) (cadr tem))
                     (push (cons (car z) (cadr z)) *loop-named-vars*)))
               (when (or (null *loop-source-code*)
                       (car z) (cadr z) (cadr tem))
                     (push (cons (car z) (cadr z)) *loop-named-vars*)))
               (when (or (null *loop-source-code*)

@@ -1693,98 +1687,129 @@ code to be loaded.
         (limit-constantp nil)
         (limit-value nil)
         )
         (limit-constantp nil)
         (limit-value nil)
         )

-     (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)
-         (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))
-         (loop-make-iteration-var indexv form indexv-type))
-        ((:upto :to :downto :above :below)
-         (cond ((loop-tequal prep :upto) (setq inclusive-iteration
-                                               (setq dir ':up)))
-               ((loop-tequal prep :to) (setq inclusive-iteration t))
-               ((loop-tequal prep :downto) (setq inclusive-iteration
-                                                 (setq dir ':down)))
-               ((loop-tequal prep :above) (setq dir ':down))
-               ((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))
-         (setq endform (if limit-constantp
-                           `',limit-value
-                           (loop-make-var
-                             (gensym "LOOP-LIMIT-") form indexv-type))))
-        (:by
-          (multiple-value-setq (form stepby-constantp stepby)
-            (loop-constant-fold-if-possible form indexv-type))
-          (unless stepby-constantp
-            (loop-make-var (setq stepby (gensym "LOOP-STEP-BY-"))
-                           form
-                           indexv-type)))
-        (t (loop-error
-             "~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"))
-       (setq odir dir))
-     (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-var
-        indexv
-        (setq start-constantp t
-              start-value (or (loop-typed-init indexv-type) 0))
-        indexv-type))
-     (cond ((member dir '(nil :up))
-           (when (or limit-given default-top)
-             (unless limit-given
-               (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))))
-          (t (unless start-given
-               (unless default-top
-                 (loop-error "don't know where to start stepping"))
-               (push `(setq ,indexv (1- ,default-top)) *loop-prologue*))
-             (when (and default-top (not endform))
-               (setq endform (loop-typed-init indexv-type)
-                     inclusive-iteration t))
-             (when endform (setq testfn (if inclusive-iteration  '< '<=)))
-             (setq step
-                   (if (eql stepby 1) `(1- ,indexv) `(- ,indexv ,stepby)))))
-     (when testfn
-       (setq test
-            `(,testfn ,indexv ,endform)))
-     (when step-hack
-       (setq step-hack
-            `(,variable ,step-hack)))
-     (let ((first-test test) (remaining-tests test))
-       (when (and stepby-constantp start-constantp limit-constantp)
-        (when (setq first-test
-                    (funcall (symbol-function testfn)
-                             start-value
-                             limit-value))
-          (setq remaining-tests t)))
-       `(() (,indexv ,step)
-        ,remaining-tests ,step-hack () () ,first-test ,step-hack))))
+     (flet ((assert-index-for-arithmetic (index)
+             (unless (atom index)
+               (loop-error "Arithmetic index must be an atom."))))
+       (when variable (loop-make-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)
+           (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))
+           (assert-index-for-arithmetic indexv)
+           ;; KLUDGE: loop-make-var generates a temporary symbol for
+           ;; indexv if it is NIL. We have to use it to have the index
+           ;; actually count
+           (setq indexv (loop-make-var indexv form indexv-type)))
+          ((:upto :to :downto :above :below)
+           (cond ((loop-tequal prep :upto) (setq inclusive-iteration
+                                                 (setq dir ':up)))
+                 ((loop-tequal prep :to) (setq inclusive-iteration t))
+                 ((loop-tequal prep :downto) (setq inclusive-iteration
+                                                   (setq dir ':down)))
+                 ((loop-tequal prep :above) (setq dir ':down))
+                 ((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 `(and ,indexv-type real)))
+           (setq endform (if limit-constantp
+                             `',limit-value
+                             (loop-make-var
+                                (gensym "LOOP-LIMIT-") form
+                                `(and ,indexv-type real)))))
+          (:by
+           (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)))
+          (t (loop-error
+                "~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"))
+        (setq odir dir))
+       (when (and sequence-variable (not sequencep))
+        (loop-error "missing OF or IN phrase in sequence path"))
+       ;; Now fill in the defaults.
+       (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
+          ;; DUPLICATE KLUDGE: loop-make-var generates a temporary
+          ;; symbol for indexv if it is NIL. See also the comment in
+          ;; the (:from :downfrom :upfrom) case
+          (progn
+            (assert-index-for-arithmetic indexv)
+            (setq indexv
+                  (loop-make-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
+                 (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))))
+            (t (unless start-given
+                 (unless default-top
+                   (loop-error "don't know where to start stepping"))
+                 (push `(setq ,indexv (1- ,default-top)) *loop-prologue*))
+               (when (and default-top (not endform))
+                 (setq endform (loop-typed-init indexv-type)
+                       inclusive-iteration t))
+               (when endform (setq testfn (if inclusive-iteration  '< '<=)))
+               (setq step
+                     (if (eql stepby 1) `(1- ,indexv) `(- ,indexv ,stepby)))))
+       (when testfn
+        (setq test
+              `(,testfn ,indexv ,endform)))
+       (when step-hack
+        (setq step-hack
+              `(,variable ,step-hack)))
+       (let ((first-test test) (remaining-tests test))
+        (when (and stepby-constantp start-constantp limit-constantp
+                   (realp start-value) (realp limit-value))
+          (when (setq first-test
+                      (funcall (symbol-function testfn)
+                               start-value
+                               limit-value))
+            (setq remaining-tests t)))
+        `(() (,indexv ,step)
+          ,remaining-tests ,step-hack () () ,first-test ,step-hack)))))

 \f
 ;;;; interfaces to the master sequencer
 
 (defun loop-for-arithmetic (var val data-type kwd)
   (loop-sequencer
 \f
 ;;;; interfaces to the master 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))