Merge branch 'master' into textbook-dyn-scope

dyn-scope-is-bad/semantics.rkt

@@ -10,13 +10,15 @@
                      lambda λ
                      letrec
                      let
+                     let*
                      set!
                      #%top
                      #%app])
 (provide defvar deffun)
 (provide [rename-out (dyn-λ λ)
                      (dyn-λ lambda)
                      (dyn-let let)
+                     (dyn-let let*)
                      (dyn-let letrec)
                      (dyn-app #%app)
                      (dyn-set! set!)])
@@ -66,6 +68,14 @@
     ([_ ([var:id val:expr] ...) body:expr ...+]
      #'(dyn-app (dyn-λ (var ...) body ...) val ...))))
 
+(define-syntax dyn-let*
+  (syntax-rules ()
+    [(dyn-let* () body ...)
+     (dyn-let () body ...)]
+    [(dyn-let* (fst rest ...) body ...)
+     (dyn-let (fst)
+       (dyn-let* (rest ...) body ...))]))
+
 (define-syntax (dyn-set! stx)
   (syntax-parse stx
     ([_ var:id val:expr]

dyn-scope-is-bad/tests/all.rkt

@@ -64,3 +64,12 @@
           (f)))
       y))
  "")
+
+; -----
+
+(test
+ (let* ([x 1]
+        [f (lambda () x)]
+        [x 2])
+   (f))
+ 2)

fun/semantics.rkt

@@ -14,7 +14,7 @@
          let let*
 	 if and or not true false eq? equal?
 	 begin
-         ivec vlen vref
+         ivec vlen vec-ref
          pair left right pair?
 	 + - * /
 	 zero?
@@ -78,16 +78,16 @@
 
 (define ivec vector-immutable)
 (define vlen vector-length)
-(define vref vector-ref)
+(define vec-ref vector-ref)
 
 (define (pair a b)
   (ivec a b))
 (define (left p)
   (unless (= (vlen p) 2)
     (error 'left "argument must be a pair: ~a" p))
-  (vref p 0))
+  (vec-ref p 0))
 (define (right p)
   (unless (= (vlen p) 2)
     (error 'right "argument must be a pair: ~a" p))
-  (vref p 1))
+  (vec-ref p 1))
 (define (pair? v) (and (vector? v) (= (vlen v) 2)))

hof/tests/all.rkt

@@ -30,3 +30,10 @@
                       (* n (fact (- n 1)))))])
         (fact 5))
       120)
+
+(test
+ (let* ([x 1]
+        [f (lambda () x)]
+        [x 2])
+   (f))
+ 1)

scribblings/smol.scrbl

@@ -55,11 +55,11 @@ exotic quoted forms. (If you don't know what these are, ignore them.)
 @deftogether[(
 @defproc[(ivec (elem Any) ...) Vec]
 @defproc[(vlen (expr Vec)) Number]
-@defproc[(vref (vec-expr Vec) (idx-expr Number)) Any]
+@defproc[(vec-ref (vec-expr Vec) (idx-expr Number)) Any]
 )]{
 The @code{ivec} operation builds an @emph{immutable} vector of the
 elements in @code{elem}. Vector elements need not be of the same
-type. @code{vlen} computes its length, while @code{vref} indexes
+type. @code{vlen} computes its length, while @code{vec-ref} indexes
 into it (starting from @code{0}).
 }
 
@@ -160,10 +160,10 @@ operations.
 
 @deftogether[(
 @defproc[(mvec (elem Any) ...) Vec]
-@defproc[(vset! (vec Vec) (idx Num) (val Any)) Void]
+@defproc[(vec-set! (vec Vec) (idx Num) (val Any)) Void]
 )]{
-@code{mvec} creates @emph{mutable} vectors, and @code{vset!} modifies
-them. @code{vset!} cannot modify an immutable vector.
+@code{mvec} creates @emph{mutable} vectors, and @code{vec-set!} modifies
+them. @code{vec-set!} cannot modify an immutable vector.
 }
 
 @deftogether[(

state/semantics.rkt

@@ -8,13 +8,13 @@
   [except-out [all-from-out smol/fun/semantics] checked-#%app]
   [rename-out [checked-#%app #%app]])
 
-(provide mvec vset!)
+(provide mvec vec-set!)
 (provide mpair set-left! set-right!)
 
 (provide set!)
 
 (define mvec vector)
-(define vset! vector-set!)
+(define vec-set! vector-set!)
 
 (define (mpair a b)
   (mvec a b))

state/tests/all.rkt

@@ -29,7 +29,7 @@
 (test z (pair 1 2))
 
 (defvar w (mvec 1 2 3))
-(vset! w 2 4)
+(vec-set! w 2 4)
 (test w #(1 2 4))
 
 (deffun (nested-i x)