update docs to use `define-type'

document `define-predicate'

svn: r18498

original commit: 24b9078560d936d046fe14b3198432a3f64cbd1c

collects/typed-scheme/scribblings/begin.scrbl

@@ -70,7 +70,7 @@ represent these using @italic{union types}, written @scheme[(U t1 t2 ...)].
 
 @schememod[
 typed/scheme
-(define-type-alias Tree (U leaf node))
+(define-type Tree (U leaf node))
 (define-struct: leaf ([val : Number]))
 (define-struct: node ([left : Tree] [right : Tree]))
 
@@ -88,7 +88,7 @@ typed/scheme
 ]
 
 In this module, we have defined two new datatypes: @scheme[leaf] and
-@scheme[node].  We've also defined the type alias @scheme[Tree] to be
+@scheme[node].  We've also defined the type name @scheme[Tree] to be
 @scheme[(U node leaf)], which represents a binary tree of numbers.  In
 essence, we are saying that the @scheme[tree-height] function accepts
 a @scheme[Tree], which is either a @scheme[node] or a @scheme[leaf],

collects/typed-scheme/scribblings/more.scrbl

@@ -152,9 +152,9 @@ variable has type @scheme[(Integer (Listof Integer) -> Integer)].
 
 @section{New Type Names}
 
-Any type can be given a name with @scheme[define-type-alias].  
+Any type can be given a name with @scheme[define-type].  
 
-@schemeblock[(define-type-alias NN (Number -> Number))]
+@schemeblock[(define-type NN (Number -> Number))]
 
 Anywhere the name @scheme[NN] is used, it is expanded to
-@scheme[(Number -> Number)].   Type aliases may not be recursive.
+@scheme[(Number -> Number)].   Type names may not be recursive.

collects/typed-scheme/scribblings/ts-guide.scrbl

@@ -141,7 +141,7 @@ represent these using @italic{union types}, written @scheme[(U t1 t2 ...)].
 
 @schememod[
 typed-scheme
-(define-type-alias Tree (U leaf node))
+(define-type Tree (U leaf node))
 (define-struct: leaf ([val : Number]))
 (define-struct: node ([left : Tree] [right : Tree]))
 
@@ -159,7 +159,7 @@ typed-scheme
 ]
 
 In this module, we have defined two new datatypes: @scheme[leaf] and
-@scheme[node].  We've also defined the type alias @scheme[Tree] to be
+@scheme[node].  We've also defined the type name @scheme[Tree] to be
 @scheme[(U node leaf)], which represents a binary tree of numbers.  In
 essence, we are saying that the @scheme[tree-height] function accepts
 a @scheme[Tree], which is either a @scheme[node] or a @scheme[leaf],
@@ -217,7 +217,7 @@ typed-scheme
 (define-struct: Nothing ())
 (define-struct: (a) Just ([v : a]))
 
-(define-type-alias (Maybe a) (U Nothing (Just a)))
+(define-type (Maybe a) (U Nothing (Just a)))
 
 (: find (Number (Listof Number) -> (Maybe Number)))
 (define (find v l)
@@ -241,11 +241,11 @@ one element, whose type is that of the type argument to
 this case) are written before the type name, and can be referred to in
 the types of the fields.
 
-The type alias definiton
+The type definiton
 @schemeblock[
-  (define-type-alias (Maybe a) (U Nothing (Just a)))
+  (define-type (Maybe a) (U Nothing (Just a)))
 ]
-creates a parameterized alias --- @scheme[Maybe] is a potential
+creates a parameterized type --- @scheme[Maybe] is a potential
 container for whatever type is supplied.
 
 The @scheme[find] function takes a number @scheme[v] and list, and

collects/typed-scheme/scribblings/ts-reference.scrbl

@@ -206,14 +206,20 @@ structure is a substructure of @scheme[parent].  When
  Like @scheme[define-struct:], but defines an procedural structure.  
  The procdure @scheme[e] is used as the value for @scheme[prop:procedure], and must have type @scheme[proc-t].}
 
-@subsection{Type Aliases}
-@defform*[[(define-type-alias name t)
-	   (define-type-alias (name v ...) t)]]{
+@subsection{Names for Types}
+@defform*[[(define-type name t)
+	   (define-type (name v ...) t)]]{
 The first form defines @scheme[name] as type, with the same meaning as
 @scheme[t].  The second form is equivalent to
-@scheme[(define-type-alias name (All (v ...) t))].  Type aliases may
-refer to other type aliases or types defined in the same module, but
-cycles among type aliases are prohibited.}
+@scheme[(define-type name (All (v ...) t))].  Type names may
+refer to other types defined in the same module, but
+cycles among them are prohibited.}
+
+@subsection{Generating Predicates Automatically}
+@defform[(define-predicate name t)]{
+Defines @scheme[name] as a predicate for the type @scheme[t].
+@scheme[name] has the type @scheme[(Any -> Boolean : t)]. 
+@scheme[t] may not contain function types.}
 
 
 @subsection{Type Annotation and Instantiation}

collects/typed-scheme/scribblings/types.scrbl

@@ -175,7 +175,7 @@ typed/scheme
 (define-struct: None ())
 (define-struct: (a) Some ([v : a]))
 
-(define-type-alias (Opt a) (U None (Some a)))
+(define-type (Opt a) (U None (Some a)))
 
 (: find (Number (Listof Number) -> (Opt Number)))
 (define (find v l)
@@ -199,11 +199,11 @@ one element, whose type is that of the type argument to
 this case) are written before the type name, and can be referred to in
 the types of the fields.
 
-The type alias definiton
+The type definiton
 @schemeblock[
-  (define-type-alias (Opt a) (U None (Some a)))
+  (define-type (Opt a) (U None (Some a)))
 ]
-creates a parameterized alias --- @scheme[Opt] is a potential
+creates a parameterized type --- @scheme[Opt] is a potential
 container for whatever type is supplied.
 
 The @scheme[find] function takes a number @scheme[v] and list, and