Merge branch 'stable-2.0'
[bpt/guile.git] / module / language / tree-il / peval.scm
index bd92edc..8a60d7b 100644 (file)
@@ -79,9 +79,6 @@
     (tree-il-fold (lambda (exp res)
                     (let ((res (proc exp)))
                       (if res (k res) #f)))
-                  (lambda (exp res)
-                    (let ((res (proc exp)))
-                      (if res (k res) #f)))
                   (lambda (exp res) #f)
                   #f exp)))
 
     (($ <primitive-ref>) #t)
     (($ <module-ref>) #t)
     (($ <toplevel-ref>) #t)
-    (($ <application> _
-        ($ <primitive-ref> _ (? singly-valued-primitive?))) #t)
-    (($ <application> _ ($ <primitive-ref> _ 'values) (val)) #t)
+    (($ <primcall> _ (? singly-valued-primitive?)) #t)
+    (($ <primcall> _ 'values (val)) #t)
     (($ <lambda>) #t)
+    (($ <conditional> _ test consequent alternate)
+     (and (singly-valued-expression? consequent)
+          (singly-valued-expression? alternate)))
     (else #f)))
 
 (define (truncate-values x)
   "Discard all but the first value of X."
   (if (singly-valued-expression? x)
       x
-      (make-application (tree-il-src x)
-                        (make-primitive-ref #f 'values)
-                        (list x))))
+      (make-primcall (tree-il-src x) 'values (list x))))
 
 ;; Peval will do a one-pass analysis on the source program to determine
 ;; the set of assigned lexicals, and to identify unreferenced and
         (let ((var (cdr (vhash-assq gensym res))))
           (set-var-refcount! var (1+ (var-refcount var)))
           res))
-       (_ res)))
-   (lambda (exp res)
-     (match exp
        (($ <lambda-case> src req opt rest kw init gensyms body alt)
         (fold (lambda (name sym res)
                 (vhash-consq sym (make-var name sym 0 #f) res))
   (%set-operand-residual-value!
    op
    (match val
-    (($ <application> src ($ <primitive-ref> _ 'values) (first))
+    (($ <primcall> src 'values (first))
      ;; The continuation of a residualized binding does not need the
      ;; introduced `values' node, so undo the effects of truncation.
      first)
@@ -393,18 +387,15 @@ top-level bindings from ENV and return the resulting expression."
 
   (define local-toplevel-env
     ;; The top-level environment of the module being compiled.
-    (match exp
-      (($ <toplevel-define> _ name)
-       (vhash-consq name #t env))
-      (($ <sequence> _ exps)
-       (fold (lambda (x r)
-               (match x
-                 (($ <toplevel-define> _ name)
-                  (vhash-consq name #t r))
-                 (_ r)))
-             env
-             exps))
-      (_ env)))
+    (let ()
+      (define (env-folder x env)
+        (match x
+          (($ <toplevel-define> _ name)
+           (vhash-consq name #t env))
+          (($ <seq> _ head tail)
+           (env-folder tail (env-folder head env)))
+          (_ env)))
+      (env-folder exp vlist-null)))
 
   (define (local-toplevel? name)
     (vhash-assq name local-toplevel-env))
@@ -442,6 +433,47 @@ top-level bindings from ENV and return the resulting expression."
   (define (lexical-refcount sym)
     (var-refcount (lookup-var sym)))
 
+  (define (with-temporaries src exps refcount can-copy? k)
+    (let* ((pairs (map (match-lambda
+                        ((and exp (? can-copy?))
+                         (cons #f exp))
+                        (exp
+                         (let ((sym (gensym "tmp ")))
+                           (record-new-temporary! 'tmp sym refcount)
+                           (cons sym exp))))
+                       exps))
+           (tmps (filter car pairs)))
+      (match tmps
+        (() (k exps))
+        (tmps
+         (make-let src
+                   (make-list (length tmps) 'tmp)
+                   (map car tmps)
+                   (map cdr tmps)
+                   (k (map (match-lambda
+                            ((#f . val) val)
+                            ((sym . _)
+                             (make-lexical-ref #f 'tmp sym)))
+                           pairs)))))))
+
+  (define (make-begin0 src first second)
+    (make-let-values
+     src
+     first
+     (let ((vals (gensym "vals ")))
+       (record-new-temporary! 'vals vals 1)
+       (make-lambda-case
+        #f
+        '() #f 'vals #f '() (list vals)
+        (make-seq
+         src
+         second
+         (make-primcall #f 'apply
+                        (list
+                         (make-primitive-ref #f 'values)
+                         (make-lexical-ref #f 'vals vals))))
+        #f))))
+
   ;; ORIG has been alpha-renamed to NEW.  Analyze NEW and record a link
   ;; from it to ORIG.
   ;;
@@ -484,15 +516,13 @@ top-level bindings from ENV and return the resulting expression."
               (values #t results))))
         (lambda _
           (values #f '()))))
-
     (define (make-values src values)
       (match values
         ((single) single)               ; 1 value
         ((_ ...)                        ; 0, or 2 or more values
-         (make-application src (make-primitive-ref src 'values)
-                           values))))
+         (make-primcall src 'values values))))
     (define (residualize-call)
-      (make-application src (make-primitive-ref #f name) args))
+      (make-primcall src name args))
     (cond
      ((every const? args)
       (let-values (((success? values)
@@ -526,27 +556,25 @@ top-level bindings from ENV and return the resulting expression."
              ($ <toplevel-ref>)
              ($ <module-ref>)
              ($ <primitive-ref>)
-             ($ <dynref>)
              ($ <lexical-set>)          ; FIXME: these set! expressions
              ($ <toplevel-set>)         ; could return zero values in
              ($ <toplevel-define>)      ; the future
              ($ <module-set>)           ;
-             ($ <dynset>)               ;
-             ($ <application> src
-                ($ <primitive-ref> _ (? singly-valued-primitive?))))
+             ($ <primcall> src (? singly-valued-primitive?)))
          (and (<= nmin 1) (or (not nmax) (>= nmax 1))
-              (make-application src (make-lambda #f '() consumer) (list exp))))
+              (make-call src (make-lambda #f '() consumer) (list exp))))
 
         ;; Statically-known number of values.
-        (($ <application> src ($ <primitive-ref> _ 'values) vals)
+        (($ <primcall> src 'values vals)
          (and (<= nmin (length vals)) (or (not nmax) (>= nmax (length vals)))
-              (make-application src (make-lambda #f '() consumer) vals)))
+              (make-call src (make-lambda #f '() consumer) vals)))
 
         ;; Not going to copy code into both branches.
         (($ <conditional>) #f)
 
         ;; Bail on other applications.
-        (($ <application>) #f)
+        (($ <call>) #f)
+        (($ <primcall>) #f)
 
         ;; Bail on prompt and abort.
         (($ <prompt>) #f)
@@ -572,20 +600,9 @@ top-level bindings from ENV and return the resulting expression."
                 (make-let-values src exp
                                  (make-lambda-case src2 req opt rest kw
                                                    inits gensyms body #f)))))
-        (($ <dynwind> src winder body unwinder)
-         (let ((body (loop body)))
-           (and body
-                (make-dynwind src winder body unwinder))))
-        (($ <dynlet> src fluids vals body)
-         (let ((body (loop body)))
-           (and body
-                (make-dynlet src fluids vals body))))
-        (($ <sequence> src exps)
-         (match exps
-           ((head ... tail)
-            (let ((tail (loop tail)))
-              (and tail
-                   (make-sequence src (append head (list tail)))))))))))
+        (($ <seq> src head tail)
+         (let ((tail (loop tail)))
+           (and tail (make-seq src head tail)))))))
 
   (define compute-effects
     (make-effects-analyzer assigned-lexical?))
@@ -632,7 +649,7 @@ top-level bindings from ENV and return the resulting expression."
                (if (null? effects)
                    body
                    (let ((effect-vals (map operand-residual-value effects)))
-                     (make-sequence #f (reverse (cons body effect-vals)))))))
+                     (list->seq #f (reverse (cons body effect-vals)))))))
           (if (null? values)
               body
               (let ((values (reverse values)))
@@ -677,8 +694,6 @@ top-level bindings from ENV and return the resulting expression."
   (define (small-expression? x limit)
     (let/ec k
       (tree-il-fold
-       (lambda (x res)                  ; leaf
-         (1+ res))
        (lambda (x res)                  ; down
          (1+ res))
        (lambda (x res)                  ; up
@@ -869,16 +884,15 @@ top-level bindings from ENV and return the resulting expression."
              (let ((exp (for-effect exp)))
                (if (void? exp)
                    exp
-                   (make-sequence src (list exp (make-void #f)))))
+                   (make-seq src exp (make-void #f))))
              (begin
                (record-operand-use op)
                (make-lexical-set src name (operand-sym op) (for-value exp))))))
       (($ <let> src
           (names ... rest)
           (gensyms ... rest-sym)
-          (vals ... ($ <application> _ ($ <primitive-ref> _ 'list) rest-args))
-          ($ <application> asrc
-             ($ <primitive-ref> _ (or 'apply '@apply))
+          (vals ... ($ <primcall> _ 'list rest-args))
+          ($ <primcall> asrc 'apply
              (proc args ...
                    ($ <lexical-ref> _
                       (? (cut eq? <> rest))
@@ -892,7 +906,7 @@ top-level bindings from ENV and return the resulting expression."
                     (append names tmps)
                     (append gensyms tmp-syms)
                     (append vals rest-args)
-                    (make-application
+                    (make-call
                      asrc
                      proc
                      (append args
@@ -934,14 +948,14 @@ top-level bindings from ENV and return the resulting expression."
               (body (loop body env counter ctx)))
          (cond
           ((const? body)
-           (for-tail (make-sequence src (append vals (list body)))))
+           (for-tail (list->seq src (append vals (list body)))))
           ((and (lexical-ref? body)
                 (memq (lexical-ref-gensym body) new))
            (let ((sym (lexical-ref-gensym body))
                  (pairs (map cons new vals)))
              ;; (let ((x foo) (y bar) ...) x) => (begin bar ... foo)
              (for-tail
-              (make-sequence
+              (list->seq
                src
                (append (map cdr (alist-delete sym pairs eq?))
                        (list (assq-ref pairs sym)))))))
@@ -993,6 +1007,23 @@ top-level bindings from ENV and return the resulting expression."
        ;; reconstruct the let-values, pevaling the consumer.
        (let ((producer (for-values producer)))
          (or (match consumer
+               (($ <lambda-case> src (req-name) #f #f #f () (req-sym) body #f)
+                (for-tail
+                 (make-let src (list req-name) (list req-sym) (list producer)
+                           body)))
+               ((and ($ <lambda-case> src () #f rest #f () (rest-sym) body #f)
+                     (? (lambda _ (singly-valued-expression? producer))))
+                (let ((tmp (gensym "tmp ")))
+                  (record-new-temporary! 'tmp tmp 1)
+                  (for-tail
+                   (make-let
+                    src (list 'tmp) (list tmp) (list producer)
+                    (make-let
+                     src (list rest) (list rest-sym)
+                     (list
+                      (make-primcall #f 'list
+                                     (list (make-lexical-ref #f 'tmp tmp))))
+                     body)))))
                (($ <lambda-case> src req opt rest #f inits gensyms body #f)
                 (let* ((nmin (length req))
                        (nmax (and (not rest) (+ nmin (if opt (length opt) 0)))))
@@ -1002,54 +1033,8 @@ top-level bindings from ENV and return the resulting expression."
                    (else #f))))
                (_ #f))
              (make-let-values lv-src producer (for-tail consumer)))))
-      (($ <dynwind> src winder body unwinder)
-       (let ((pre (for-value winder))
-             (body (for-tail body))
-             (post (for-value unwinder)))
-         (cond
-          ((not (constant-expression? pre))
-           (cond
-            ((not (constant-expression? post))
-             (let ((pre-sym (gensym "pre-")) (post-sym (gensym "post-")))
-               (record-new-temporary! 'pre pre-sym 1)
-               (record-new-temporary! 'post post-sym 1)
-               (make-let src '(pre post) (list pre-sym post-sym) (list pre post)
-                         (make-dynwind src
-                                       (make-lexical-ref #f 'pre pre-sym)
-                                       body
-                                       (make-lexical-ref #f 'post post-sym)))))
-            (else
-             (let ((pre-sym (gensym "pre-")))
-               (record-new-temporary! 'pre pre-sym 1)
-               (make-let src '(pre) (list pre-sym) (list pre)
-                         (make-dynwind src
-                                       (make-lexical-ref #f 'pre pre-sym)
-                                       body
-                                       post))))))
-          ((not (constant-expression? post))
-           (let ((post-sym (gensym "post-")))
-             (record-new-temporary! 'post post-sym 1)
-             (make-let src '(post) (list post-sym) (list post)
-                       (make-dynwind src
-                                     pre
-                                     body
-                                     (make-lexical-ref #f 'post post-sym)))))
-          (else
-           (make-dynwind src pre body post)))))
-      (($ <dynlet> src fluids vals body)
-       (make-dynlet src (map for-value fluids) (map for-value vals)
-                    (for-tail body)))
-      (($ <dynref> src fluid)
-       (make-dynref src (for-value fluid)))
-      (($ <dynset> src fluid exp)
-       (make-dynset src (for-value fluid) (for-value exp)))
       (($ <toplevel-ref> src (? effect-free-primitive? name))
-       (if (local-toplevel? name)
-           exp
-           (let ((exp (resolve-primitives! exp cenv)))
-             (if (primitive-ref? exp)
-                 (for-tail exp)
-                 exp))))
+       exp)
       (($ <toplevel-ref>)
        ;; todo: open private local bindings.
        exp)
@@ -1078,7 +1063,8 @@ top-level bindings from ENV and return the resulting expression."
       (($ <conditional> src condition subsequent alternate)
        (define (call-with-failure-thunk exp proc)
          (match exp
-           (($ <application> _ _ ()) (proc exp))
+           (($ <call> _ _ ()) (proc exp))
+           (($ <primcall> _ _ ()) (proc exp))
            (($ <const>) (proc exp))
            (($ <void>) (proc exp))
            (($ <lexical-ref>) (proc exp))
@@ -1091,13 +1077,12 @@ top-level bindings from ENV and return the resulting expression."
                 (make-lambda
                  #f '()
                  (make-lambda-case #f '() #f #f #f '() '() exp #f)))
-               (proc (make-application #f (make-lexical-ref #f 'failure t)
-                                       '())))))))
+               (proc (make-call #f (make-lexical-ref #f 'failure t)
+                                '())))))))
        (define (simplify-conditional c)
          (match c
            ;; Swap the arms of (if (not FOO) A B), to simplify.
-           (($ <conditional> src
-               ($ <application> _ ($ <primitive-ref> _ 'not) (pred))
+           (($ <conditional> src ($ <primcall> _ 'not (pred))
                subsequent alternate)
             (simplify-conditional
              (make-conditional src pred alternate subsequent)))
@@ -1149,17 +1134,58 @@ top-level bindings from ENV and return the resulting expression."
           (simplify-conditional
            (make-conditional src c (for-tail subsequent)
                              (for-tail alternate))))))
-      (($ <application> src
-          ($ <primitive-ref> _ '@call-with-values)
+      (($ <primcall> src 'call-with-values
           (producer
            ($ <lambda> _ _
               (and consumer
                    ;; No optional or kwargs.
                    ($ <lambda-case>
                       _ req #f rest #f () gensyms body #f)))))
-       (for-tail (make-let-values src (make-application src producer '())
+       (for-tail (make-let-values src (make-call src producer '())
                                   consumer)))
-      (($ <application> src ($ <primitive-ref> _ 'values) exps)
+      (($ <primcall> src 'dynamic-wind (w thunk u))
+       (for-tail
+        (with-temporaries
+         src (list w u) 2 constant-expression?
+         (match-lambda
+          ((w u)
+           (make-seq
+            src
+            (make-seq
+             src
+             (make-conditional
+              src
+              ;; fixme: introduce logic to fold thunk?
+              (make-primcall src 'thunk? (list u))
+              (make-call src w '())
+              (make-primcall
+               src 'scm-error
+               (list
+                (make-const #f 'wrong-type-arg)
+                (make-const #f "dynamic-wind")
+                (make-const #f "Wrong type (expecting thunk): ~S")
+                (make-primcall #f 'list (list u))
+                (make-primcall #f 'list (list u)))))
+             (make-primcall src 'wind (list w u)))
+            (make-begin0 src
+                         (make-call src thunk '())
+                         (make-seq src
+                                   (make-primcall src 'unwind '())
+                                   (make-call src u '())))))))))
+
+      (($ <primcall> src 'with-fluid* (f v thunk))
+       (for-tail
+        (with-temporaries
+         src (list f v thunk) 1 constant-expression?
+         (match-lambda
+          ((f v thunk)
+           (make-seq src
+                     (make-primcall src 'push-fluid (list f v))
+                     (make-begin0 src
+                                  (make-call src thunk '())
+                                  (make-primcall src 'pop-fluid '()))))))))
+
+      (($ <primcall> src 'values exps)
        (cond
         ((null? exps)
          (if (eq? ctx 'effect)
@@ -1171,10 +1197,10 @@ top-level bindings from ENV and return the resulting expression."
                       ((value test effect) #t)
                       (else (null? (cdr vals))))
                     (every singly-valued-expression? vals))
-               (for-tail (make-sequence src (append (cdr vals) (list (car vals)))))
-               (make-application src (make-primitive-ref #f 'values) vals))))))
-      (($ <application> src (and apply ($ <primitive-ref> _ (or 'apply '@apply)))
-          (proc args ... tail))
+               (for-tail (list->seq src (append (cdr vals) (list (car vals)))))
+               (make-primcall src 'values vals))))))
+
+      (($ <primcall> src 'apply (proc args ... tail))
        (let lp ((tail* (find-definition tail 1)) (speculative? #t))
          (define (copyable? x)
            ;; Inlining a result from find-definition effectively copies it,
@@ -1184,159 +1210,191 @@ top-level bindings from ENV and return the resulting expression."
          (match tail*
            (($ <const> _ (args* ...))
             (let ((args* (map (cut make-const #f <>) args*)))
-              (for-tail (make-application src proc (append args args*)))))
-           (($ <application> _ ($ <primitive-ref> _ 'cons)
+              (for-tail (make-call src proc (append args args*)))))
+           (($ <primcall> _ 'cons
                ((and head (? copyable?)) (and tail (? copyable?))))
-            (for-tail (make-application src apply
-                                        (cons proc
-                                              (append args (list head tail))))))
-           (($ <application> _ ($ <primitive-ref> _ 'list)
+            (for-tail (make-primcall src 'apply
+                                     (cons proc
+                                           (append args (list head tail))))))
+           (($ <primcall> _ 'list
                (and args* ((? copyable?) ...)))
-            (for-tail (make-application src proc (append args args*))))
+            (for-tail (make-call src proc (append args args*))))
            (tail*
             (if speculative?
                 (lp (for-value tail) #f)
                 (let ((args (append (map for-value args) (list tail*))))
-                  (make-application src apply
-                                    (cons (for-value proc) args))))))))
-      (($ <application> src orig-proc orig-args)
+                  (make-primcall src 'apply
+                                 (cons (for-value proc) args))))))))
+
+      (($ <primcall> src (? constructor-primitive? name) args)
+       (cond
+        ((and (memq ctx '(effect test))
+              (match (cons name args)
+                ((or ('cons _ _)
+                     ('list . _)
+                     ('vector . _)
+                     ('make-prompt-tag)
+                     ('make-prompt-tag ($ <const> _ (? string?))))
+                 #t)
+                (_ #f)))
+         ;; Some expressions can be folded without visiting the
+         ;; arguments for value.
+         (let ((res (if (eq? ctx 'effect)
+                        (make-void #f)
+                        (make-const #f #t))))
+           (for-tail (list->seq src (append args (list res))))))
+        (else
+         (match (cons name (map for-value args))
+           (('cons x ($ <const> _ (? (cut eq? <> '()))))
+            (make-primcall src 'list (list x)))
+           (('cons x ($ <primcall> _ 'list elts))
+            (make-primcall src 'list (cons x elts)))
+           ((name . args)
+            (make-primcall src name args))))))
+
+      (($ <primcall> src 'thunk? (proc))
+       (case ctx
+         ((effect)
+          (for-tail (make-seq src proc (make-void src))))
+         (else
+          (match (for-value proc)
+            (($ <lambda> _ _ ($ <lambda-case> _ req))
+             (for-tail (make-const src (null? req))))
+            (proc
+             (match (find-definition proc 2)
+               (($ <lambda> _ _ ($ <lambda-case> _ req))
+                (for-tail (make-const src (null? req))))
+               (_
+                (make-primcall src 'thunk? (list proc)))))))))
+
+      (($ <primcall> src name args)
+       (match (cons name (map for-value args))
+         ;; FIXME: these for-tail recursions could take place outside
+         ;; an effort counter.
+         (('car ($ <primcall> src 'cons (head tail)))
+          (for-tail (make-seq src tail head)))
+         (('cdr ($ <primcall> src 'cons (head tail)))
+          (for-tail (make-seq src head tail)))
+         (('car ($ <primcall> src 'list (head . tail)))
+          (for-tail (list->seq src (append tail (list head)))))
+         (('cdr ($ <primcall> src 'list (head . tail)))
+          (for-tail (make-seq src head (make-primcall #f 'list tail))))
+                  
+         (('car ($ <const> src (head . tail)))
+          (for-tail (make-const src head)))
+         (('cdr ($ <const> src (head . tail)))
+          (for-tail (make-const src tail)))
+         (((or 'memq 'memv) k ($ <const> _ (elts ...)))
+          ;; FIXME: factor 
+          (case ctx
+            ((effect)
+             (for-tail
+              (make-seq src k (make-void #f))))
+            ((test)
+             (cond
+              ((const? k)
+               ;; A shortcut.  The `else' case would handle it, but
+               ;; this way is faster.
+               (let ((member (case name ((memq) memq) ((memv) memv))))
+                 (make-const #f (and (member (const-exp k) elts) #t))))
+              ((null? elts)
+               (for-tail
+                (make-seq src k (make-const #f #f))))
+              (else
+               (let ((t (gensym "t "))
+                     (eq (if (eq? name 'memq) 'eq? 'eqv?)))
+                 (record-new-temporary! 't t (length elts))
+                 (for-tail
+                  (make-let
+                   src (list 't) (list t) (list k)
+                   (let lp ((elts elts))
+                     (define test
+                       (make-primcall #f eq
+                                      (list (make-lexical-ref #f 't t)
+                                            (make-const #f (car elts)))))
+                     (if (null? (cdr elts))
+                         test
+                         (make-conditional src test
+                                           (make-const #f #t)
+                                           (lp (cdr elts)))))))))))
+            (else
+             (cond
+              ((const? k)
+               (let ((member (case name ((memq) memq) ((memv) memv))))
+                 (make-const #f (member (const-exp k) elts))))
+              ((null? elts)
+               (for-tail (make-seq src k (make-const #f #f))))
+              (else
+               (make-primcall src name (list k (make-const #f elts))))))))
+         (((? equality-primitive?)
+           ($ <lexical-ref> _ _ sym) ($ <lexical-ref> _ _ sym))
+          (for-tail (make-const #f #t)))
+
+         (((? effect-free-primitive?) . args)
+          (fold-constants src name args ctx))
+
+         ((name . args)
+          (make-primcall src name args))))
+
+      (($ <call> src orig-proc orig-args)
        ;; todo: augment the global env with specialized functions
        (let revisit-proc ((proc (visit orig-proc 'operator)))
          (match proc
-           (($ <primitive-ref> _ (? constructor-primitive? name))
-            (cond
-             ((and (memq ctx '(effect test))
-                   (match (cons name orig-args)
-                     ((or ('cons _ _)
-                          ('list . _)
-                          ('vector . _)
-                          ('make-prompt-tag)
-                          ('make-prompt-tag ($ <const> _ (? string?))))
-                      #t)
-                     (_ #f)))
-              ;; Some expressions can be folded without visiting the
-              ;; arguments for value.
-              (let ((res (if (eq? ctx 'effect)
-                             (make-void #f)
-                             (make-const #f #t))))
-                (for-tail (make-sequence src (append orig-args (list res))))))
-             (else
-              (match (cons name (map for-value orig-args))
-                (('cons head tail)
-                 (match tail
-                   (($ <const> src (? (cut eq? <> '())))
-                    (make-application src (make-primitive-ref #f 'list)
-                                      (list head)))
-                   (($ <application> src ($ <primitive-ref> _ 'list) elts)
-                    (make-application src (make-primitive-ref #f 'list)
-                                      (cons head elts)))
-                   (_ (make-application src proc (list head tail)))))
-                ((_ . args)
-                 (make-application src proc args))))))
-           (($ <primitive-ref> _ (? accessor-primitive? name))
-            (match (cons name (map for-value orig-args))
-              ;; FIXME: these for-tail recursions could take place outside
-              ;; an effort counter.
-              (('car ($ <application> src ($ <primitive-ref> _ 'cons) (head tail)))
-               (for-tail (make-sequence src (list tail head))))
-              (('cdr ($ <application> src ($ <primitive-ref> _ 'cons) (head tail)))
-               (for-tail (make-sequence src (list head tail))))
-              (('car ($ <application> src ($ <primitive-ref> _ 'list) (head . tail)))
-               (for-tail (make-sequence src (append tail (list head)))))
-              (('cdr ($ <application> src ($ <primitive-ref> _ 'list) (head . tail)))
-               (for-tail (make-sequence
-                          src
-                          (list head
-                                (make-application
-                                 src (make-primitive-ref #f 'list) tail)))))
-                  
-              (('car ($ <const> src (head . tail)))
-               (for-tail (make-const src head)))
-              (('cdr ($ <const> src (head . tail)))
-               (for-tail (make-const src tail)))
-              (((or 'memq 'memv) k ($ <const> _ (elts ...)))
-               ;; FIXME: factor 
-               (case ctx
-                 ((effect)
-                  (for-tail
-                   (make-sequence src (list k (make-void #f)))))
-                 ((test)
-                  (cond
-                   ((const? k)
-                    ;; A shortcut.  The `else' case would handle it, but
-                    ;; this way is faster.
-                    (let ((member (case name ((memq) memq) ((memv) memv))))
-                      (make-const #f (and (member (const-exp k) elts) #t))))
-                   ((null? elts)
-                    (for-tail
-                     (make-sequence src (list k (make-const #f #f)))))
-                   (else
-                    (let ((t (gensym "t-"))
-                          (eq (if (eq? name 'memq) 'eq? 'eqv?)))
-                      (record-new-temporary! 't t (length elts))
-                      (for-tail
-                       (make-let
-                        src (list 't) (list t) (list k)
-                        (let lp ((elts elts))
-                          (define test
-                            (make-application
-                             #f (make-primitive-ref #f eq)
-                             (list (make-lexical-ref #f 't t)
-                                   (make-const #f (car elts)))))
-                          (if (null? (cdr elts))
-                              test
-                              (make-conditional src test
-                                                (make-const #f #t)
-                                                (lp (cdr elts)))))))))))
-                 (else
-                  (cond
-                   ((const? k)
-                    (let ((member (case name ((memq) memq) ((memv) memv))))
-                      (make-const #f (member (const-exp k) elts))))
-                   ((null? elts)
-                    (for-tail (make-sequence src (list k (make-const #f #f)))))
-                   (else
-                    (make-application src proc (list k (make-const #f elts))))))))
-              ((_ . args)
-               (or (fold-constants src name args ctx)
-                   (make-application src proc args)))))
-           (($ <primitive-ref> _ (? effect-free-primitive? name))
-            (let ((args (map for-value orig-args)))
-              (or (fold-constants src name args ctx)
-                  (make-application src proc args))))
+           (($ <primitive-ref> _ name)
+            (for-tail (make-primcall src name orig-args)))
            (($ <lambda> _ _
                ($ <lambda-case> _ req opt rest #f inits gensyms body #f))
             ;; Simple case: no keyword arguments.
             ;; todo: handle the more complex cases
             (let* ((nargs (length orig-args))
                    (nreq (length req))
-                   (nopt (if opt (length opt) 0))
+                   (opt (or opt '()))
+                   (rest (if rest (list rest) '()))
+                   (nopt (length opt))
                    (key (source-expression proc)))
-              (define (inlined-application)
-                (make-let src
-                          (append req
-                                  (or opt '())
-                                  (if rest (list rest) '()))
-                          gensyms
-                          (if (> nargs (+ nreq nopt))
-                              (append (list-head orig-args (+ nreq nopt))
-                                      (list
-                                       (make-application
-                                        #f
-                                        (make-primitive-ref #f 'list)
-                                        (drop orig-args (+ nreq nopt)))))
-                              (append orig-args
-                                      (drop inits (- nargs nreq))
-                                      (if rest
-                                          (list (make-const #f '()))
-                                          '())))
-                          body))
+              (define (inlined-call)
+                (let ((req-vals (list-head orig-args nreq))
+                      (opt-vals (let lp ((args (drop orig-args nreq))
+                                         (inits inits)
+                                         (out '()))
+                                  (match inits
+                                    (() (reverse out))
+                                    ((init . inits)
+                                     (match args
+                                       (()
+                                        (lp '() inits (cons init out)))
+                                       ((arg . args)
+                                        (lp args inits (cons arg out))))))))
+                      (rest-vals (cond
+                                  ((> nargs (+ nreq nopt))
+                                   (list (make-primcall
+                                          #f 'list
+                                          (drop orig-args (+ nreq nopt)))))
+                                  (rest (list (make-const #f '())))
+                                  (else '()))))
+                  (if (>= nargs (+ nreq nopt))
+                      (make-let src
+                                (append req opt rest)
+                                gensyms
+                                (append req-vals opt-vals rest-vals)
+                                body)
+                      ;; The required argument values are in the scope
+                      ;; of the optional argument initializers.
+                      (make-let src
+                                (append req rest)
+                                (append (list-head gensyms nreq)
+                                        (last-pair gensyms))
+                                (append req-vals rest-vals)
+                                (make-let src
+                                          opt
+                                          (list-head (drop gensyms nreq) nopt)
+                                          opt-vals
+                                          body)))))
 
               (cond
                ((or (< nargs nreq) (and (not rest) (> nargs (+ nreq nopt))))
                 ;; An error, or effecting arguments.
-                (make-application src (for-call orig-proc)
-                                  (map for-value orig-args)))
+                (make-call src (for-call orig-proc) (map for-value orig-args)))
                ((or (and=> (find-counter key counter) counter-recursive?)
                     (lambda? orig-proc))
                 ;; A recursive call, or a lambda in the operator
@@ -1358,7 +1416,7 @@ top-level bindings from ENV and return the resulting expression."
                               (lp (counter-prev counter)))))))
 
                 (log 'inline-recurse key)
-                (loop (inlined-application) env counter ctx))
+                (loop (inlined-call) env counter ctx))
                (else
                 ;; An integration at the top-level, the first
                 ;; recursion of a recursive procedure, or a nested
@@ -1368,8 +1426,8 @@ top-level bindings from ENV and return the resulting expression."
                 (let/ec k
                   (define (abort)
                     (log 'inline-abort exp)
-                    (k (make-application src (for-call orig-proc)
-                                         (map for-value orig-args))))
+                    (k (make-call src (for-call orig-proc)
+                                  (map for-value orig-args))))
                   (define new-counter
                     (cond
                      ;; These first two cases will transfer effort
@@ -1389,7 +1447,7 @@ top-level bindings from ENV and return the resulting expression."
                       (make-top-counter effort-limit operand-size-limit
                                         abort key))))
                   (define result
-                    (loop (inlined-application) env new-counter ctx))
+                    (loop (inlined-call) env new-counter ctx))
                       
                   (if counter
                       ;; The nested inlining attempt succeeded.
@@ -1414,7 +1472,7 @@ top-level bindings from ENV and return the resulting expression."
                    (log 'inline-let orig-proc)
                    (for-tail
                     (make-let lsrc names syms vals
-                              (make-application src body orig-args))))
+                              (make-call src body orig-args))))
                   ;; It's possible for a `let' to go away after the
                   ;; visit due to the fact that visiting a procedure in
                   ;; value context will prune unused bindings, whereas
@@ -1422,11 +1480,10 @@ top-level bindings from ENV and return the resulting expression."
                   ;; traverse through lambdas.  In that case re-visit
                   ;; the procedure.
                   (proc (revisit-proc proc)))
-                (make-application src (for-call orig-proc)
-                                  (map for-value orig-args))))
+                (make-call src (for-call orig-proc)
+                           (map for-value orig-args))))
            (_
-            (make-application src (for-call orig-proc)
-                              (map for-value orig-args))))))
+            (make-call src (for-call orig-proc) (map for-value orig-args))))))
       (($ <lambda> src meta body)
        (case ctx
          ((effect) (make-void #f))
@@ -1439,8 +1496,7 @@ top-level bindings from ENV and return the resulting expression."
        (define (lift-applied-lambda body gensyms)
          (and (not opt) rest (not kw)
               (match body
-                (($ <application> _
-                    ($ <primitive-ref> _ '@apply)
+                (($ <primcall> _ 'apply
                     (($ <lambda> _ _ (and lcase ($ <lambda-case>)))
                      ($ <lexical-ref> _ _ sym)
                      ...))
@@ -1467,34 +1523,26 @@ top-level bindings from ENV and return the resulting expression."
                             new
                             body
                             (and alt (for-tail alt))))))
-      (($ <sequence> src exps)
-       (let lp ((exps exps) (effects '()))
-         (match exps
-           ((last)
-            (if (null? effects)
-                (for-tail last)
-                (make-sequence
-                 src
-                 (reverse (cons (for-tail last) effects)))))
-           ((head . rest)
-            (let ((head (for-effect head)))
-              (cond
-               ((sequence? head)
-                (lp (append (sequence-exps head) rest) effects))
-               ((void? head)
-                (lp rest effects))
-               (else
-                (lp rest (cons head effects)))))))))
-      (($ <prompt> src tag body handler)
+      (($ <seq> src head tail)
+       (let ((head (for-effect head))
+             (tail (for-tail tail)))
+         (if (void? head)
+             tail
+             (make-seq src
+                       (if (and (seq? head)
+                                (void? (seq-tail head)))
+                           (seq-head head)
+                           head)
+                       tail))))
+      (($ <prompt> src escape-only? tag body handler)
        (define (make-prompt-tag? x)
          (match x
-           (($ <application> _ ($ <primitive-ref> _ 'make-prompt-tag)
-               (or () ((? constant-expression?))))
+           (($ <primcall> _ 'make-prompt-tag (or () ((? constant-expression?))))
             #t)
            (_ #f)))
 
        (let ((tag (for-value tag))
-             (body (for-tail body)))
+             (body (if escape-only? (for-tail body) (for-value body))))
          (cond
           ((find-definition tag 1)
            (lambda (val op)
@@ -1504,31 +1552,26 @@ top-level bindings from ENV and return the resulting expression."
                 ;; for this <prompt>, so we can elide the <prompt>
                 ;; entirely.
                 (unrecord-operand-uses op 1)
-                body))
-          ((find-definition tag 2)
-           (lambda (val op)
-             (and (make-prompt-tag? val)
-                  (abort? body)
-                  (tree-il=? (abort-tag body) tag)))
-           => (lambda (val op)
-                ;; (let ((t (make-prompt-tag)))
-                ;;   (call-with-prompt t
-                ;;     (lambda () (abort-to-prompt t val ...))
-                ;;     (lambda (k arg ...) e ...)))
-                ;; => (let-values (((k arg ...) (values values val ...)))
-                ;;      e ...)
-                (unrecord-operand-uses op 2)
-                (for-tail
-                 (make-let-values
-                  src
-                  (make-application #f (make-primitive-ref #f 'apply)
-                                    `(,(make-primitive-ref #f 'values)
-                                      ,(make-primitive-ref #f 'values)
-                                      ,@(abort-args body)
-                                      ,(abort-tail body)))
-                  (for-value handler)))))
+                (for-tail (if escape-only? body (make-call src body '())))))
           (else
-           (make-prompt src tag body (for-value handler))))))
+           (let ((handler (for-value handler)))
+             (define (escape-only-handler? handler)
+               (match handler
+                 (($ <lambda> _ _
+                     ($ <lambda-case> _ (_ . _) _ _ _ _ (k . _) body #f))
+                  (not (tree-il-any
+                        (match-lambda
+                         (($ <lexical-ref> _ _ (? (cut eq? <> k))) #t)
+                         (_ #f))
+                        body)))
+                 (else #f)))
+             (if (and (not escape-only?) (escape-only-handler? handler))
+                 ;; Prompt transitioning to escape-only; transition body
+                 ;; to be an expression.
+                 (for-tail
+                  (make-prompt src #t tag (make-call #f body '()) handler))
+                 (make-prompt src escape-only? tag body handler)))))))
+
       (($ <abort> src tag args tail)
        (make-abort src (for-value tag) (map for-value args)
                    (for-value tail))))))