reference-manual work

svn: r6495

collects/scribble/manual.ss

@@ -34,9 +34,9 @@
       [(_ lang rest ...)
        (with-syntax ([modtag (datum->syntax-object
                               #'here
-                              '(unsyntax (schemefont "#module "))
+                              `(unsyntax (schemefont ,(format "#module ~a" (syntax-e #'lang))))
                               #'lang)])
-         #'(schemeblock modtag lang rest ...))]))
+         #'(schemeblock modtag rest ...))]))
 
   (define (to-element/result s)
     (make-element "schemeresult" (list (to-element/no-color s))))
@@ -137,8 +137,17 @@
 
   ;; ----------------------------------------
 
+  (provide margin-note)
+  
+  (define (margin-note . c)
+    (make-styled-paragraph (list (make-element "refcontent"
+                                               c))
+                           "refpara"))
+
+  ;; ----------------------------------------
+
   (provide defproc defproc* defstruct defthing defform defform* defform/none
-           specsubform specsubform/inline
+           specform specsubform specsubform/inline
            var svar void-const undefined-const)
 
   (define void-const
@@ -190,11 +199,15 @@
   (define-syntax specsubform
     (syntax-rules ()
       [(_ spec desc ...)
-       (*specsubform 'spec (lambda () (schemeblock0 spec)) (lambda () (list desc ...)))]))
+       (*specsubform 'spec #f (lambda () (schemeblock0 spec)) (lambda () (list desc ...)))]))
+  (define-syntax specform
+    (syntax-rules ()
+      [(_ spec desc ...)
+       (*specsubform 'spec #t (lambda () (schemeblock0 spec)) (lambda () (list desc ...)))]))
   (define-syntax specsubform/inline
     (syntax-rules ()
       [(_ spec desc ...)
-       (*specsubform 'spec #f (lambda () (list desc ...)))]))
+       (*specsubform 'spec #f #f (lambda () (list desc ...)))]))
   (define-syntax defthing
     (syntax-rules ()
       [(_ id result desc ...)
@@ -429,9 +442,9 @@
               forms form-procs))
         (content-thunk)))))
 
-  (define (*specsubform form form-thunk content-thunk)
+  (define (*specsubform form has-kw? form-thunk content-thunk)
     (parameterize ([current-variable-list
-                    (append (let loop ([form form])
+                    (append (let loop ([form (if has-kw? (cdr form) form)])
                               (cond
                                [(symbol? form) (if (meta-symbol? form)
                                                    null

collects/scribble/scheme.ss

@@ -1,7 +1,8 @@
 (module scheme mzscheme
   (require "struct.ss"
            "basic.ss"
-           (lib "class.ss"))
+           (lib "class.ss")
+           (lib "for.ss"))
 
   (provide define-code
            to-element
@@ -92,7 +93,8 @@
                 [l (syntax-line c)])
             (let ([new-line? (and l (l . > . line))])
               (when new-line?
-                (out "\n" no-color)
+                (for ([i (in-range (- l line))])
+                  (out "\n" no-color))
                 (set! line l)
                 (set! col-map next-col-map)
                 (set! next-col-map (make-hash-table 'equal))

collects/scribblings/guide/apply.scrbl

@@ -0,0 +1,50 @@
+#reader(lib "docreader.ss" "scribble")
+@require[(lib "manual.ss" "scribble")]
+@require[(lib "eval.ss" "scribble")]
+@require["guide-utils.ss"]
+
+@title[#:tag "guide:application"]{Procedure Applications}
+
+An expression of the form
+
+@specsubform[
+(_proc-expr _arg-expr ...)
+]
+
+is a procedure application when @scheme[_proc-expr] is not an
+identifier that is bound as a transformer. The @scheme[...] in this
+syntactic sketch means ``zero or more repetitions of the preceeding
+element;'' that is, zero or more @scheme[_arg-expr]s.
+
+A procedure application is evaluated by first evaluating the
+@scheme[_proc-expr] and all @scheme[_arg-expr]s in order (left to
+right). Then, if @scheme[_proc-expr] produced a procedure that accepts
+as many arguments as supplied @scheme[_arg-expr]s, the procedure is
+aplied. Otherwise, an exception is raised.
+
+@examples[
+(cons 1 null)
+((lambda (x y z) (+ x y z)) 1 2 3)
+(cons 1 2 3)
+(1 2 3)
+]
+
+Some procedures, such as @scheme[cons], accept a fixed number of
+arguments. Some procedures, such as @scheme[list], accept any number
+of arguments. Some procedures accept a range of argument counts; for
+example @scheme[substring] accepts either two or three arguments.
+
+Some procedures accept @defterm{keyword arguments} in addition to
+by-position arguments. To supply a keyword argument, include a keyword
+followed by the addociated argument value. The order of keyword
+arguments does not matter, nor does their position relative to
+non-keyword arguments (as long as they follow the procedure
+expression); keyword arguments are recognized by an applied procedure
+using only the associated keyword, not the order.
+
+@examples[
+(need-an-example 1 #:arg 2)
+(need-an-example #:arg 2 1)
+]
+
+@refdetails["mz:application"]{procedure applications}

collects/scribblings/guide/binding.scrbl

@@ -0,0 +1,82 @@
+#reader(lib "docreader.ss" "scribble")
+@require[(lib "manual.ss" "scribble")]
+@require[(lib "eval.ss" "scribble")]
+@require["guide-utils.ss"]
+
+@title{Identifiers and Binding}
+
+The context of an expression determines the meaning of identifiers
+that appear in the expression. In particular, starting a module with
+the language @schememodname[big], as in
+
+@schememod[big]
+
+means that, within the module, the identifiers described in this guide
+have the the meaning described here: @scheme[cons] refers to the
+procedure that creates a pair, @scheme[car] refers to the procedure
+that extracts the first element of a pair, and so on.
+
+@margin-note{For information on the syntax of identifiers, see
+@secref["symbols"].}
+
+Forms like @scheme[define], @scheme[lambda], and @scheme[let]
+associate a meaning with one or more identifiers; that is, they
+@defterm{bind} identifier. The part of the program for which the
+binding applies is the @defterm{scope} of the binding. The set of
+bindings in effect for a given expression is the expression's
+@defterm{environment}.
+
+For example, in
+
+@schememod[
+big
+
+(define f
+  (lambda (x)
+    (let ([y 5])
+      (+ x y))))
+
+(f 10)
+]
+
+the @scheme[define] is a binding of @scheme[f], the @scheme[lambda]
+has a binding for @scheme[x], and the @scheme[let] has a binding for
+@scheme[y]. The scope of the binding for @scheme[f] is the entire
+module; the scope of the @scheme[x] binding is @scheme[(let ([y 5]) (+
+x y))]; and the scope of the @scheme[y] binding is just @scheme[(+ x
+y)]. The environment of @scheme[(+ x y)] includes bindings for
+@scheme[y], @scheme[x], and @scheme[f], as well as everything in
+@schememodname[big].
+
+A module-level @scheme[define] can bind only identifiers that are not
+already bound within the module. For example, @scheme[(define cons 1)]
+is a syntax error in a @schememodname[big] module, since @scheme[cons]
+is provided by @schememodname[big]. A local @scheme[define] or other
+binding forms, however, can give a new local binding for an identifier
+that already has a binding; such a binding @defterm{shadows} the
+existing binding.
+
+@defexamples[
+(define f
+  (lambda (append)
+    (define cons (append "ugly" "confusing"))
+    (let ([append 'this-was])
+      (list append cons))))
+(f list)
+]
+
+Even identifiers like @scheme[define] and @scheme[lambda] get their
+meanings from bindings, though they have @defterm{transformer}
+bindings (whcih means that they define syntactic forms) instead of
+value bindings. Since @scheme[define] has a transformer binding, the
+identifier @schemeidfont{define} cannot be used by itself to get a
+value. However, the normal binding for @schemeidfont{define} can be
+shadowed.
+
+@examples[
+define
+(eval:alts (let ([#, @schemeidfont{define} 5]) #, @schemeidfont{define}) (let ([define 5]) define))
+]
+
+Shadowing standard bindings in this way is rarely a good idea, but the
+possibility is an inherent part of Scheme's flexibility.

collects/scribblings/guide/data.scrbl

@@ -5,7 +5,7 @@
 
 @title[#:tag "datatypes" #:style 'toc]{Built-In Datatypes}
 
-The @seclink["to-scheme"]{little Scheme section} introduced some of
+The @seclink["to-scheme"]{previous chapter} introduced some of
 Scheme's built-in datatype: numbers, booleans, strings, lists, and
 procedures. This section provides a more complete coverage of the
 built-in datatypes for simple forms of data.

collects/scribblings/guide/define.scrbl

@@ -0,0 +1,10 @@
+#reader(lib "docreader.ss" "scribble")
+@require[(lib "manual.ss" "scribble")]
+@require[(lib "eval.ss" "scribble")]
+@require["guide-utils.ss"]
+
+@title{Definitions}
+
+A definition can have the form
+
+@specform[(define _id _expr)]

collects/scribblings/guide/for.scrbl

@@ -5,7 +5,7 @@
 
 @interaction-eval[(require (lib "for.ss"))]
 
-@title[#:tag "for"]{Iterations and Comprehensions}
+@title[#:tag "guide:for"]{Iterations and Comprehensions}
 
 The @scheme[for] family of syntactic forms support iteration over
 @defterm{sequences}. Lists, vectors, strings, byte strings, input
@@ -425,3 +425,5 @@ patterns that provide good performance is extensible, just like the
 set of sequence values. The documentation for a sequence constructor
 should indicate the performance impliciations of using it directly in
 a @scheme[for] @scheme[_clause].
+
+@refdetails["mz:for"]{iterations and comprehensions}

collects/scribblings/guide/forms.scrbl

@@ -3,12 +3,18 @@
 @require[(lib "eval.ss" "scribble")]
 @require["guide-utils.ss"]
 
-@title[#:tag "scheme-forms" #:style 'toc]{Programs and Expressions}
+@title[#:tag "scheme-forms" #:style 'toc]{Expressions and Definitions}
+
+The @secref["to-scheme"] chapter introduced some of Scheme's syntactic
+forms: definitions, procedure applications, conditionals, procedures,
+local binding, and some iteration forms. This section provides a more
+complete coverage of the basic Scheme syntactic forms.
 
 @local-table-of-contents[]
 
-@include-section["module-basics.scrbl"]
-
+@include-section["binding.scrbl"]
+@include-section["apply.scrbl"]
+@include-section["lambda.scrbl"]
+@include-section["define.scrbl"]
 @include-section["for.scrbl"]
 
-

collects/scribblings/guide/guide-utils.ss

@@ -22,14 +22,12 @@
     (apply item (bold name) ", " desc))
 
   (define/kw (refdetails tag #:body s)
-    (let ([c (decode-content (append (list "For more on ")
+    (apply margin-note
+           (decode-content (append (list "For more on ")
                                    s
                                    (list ", see "
                                          (refsecref tag)
-                                           ".")))])
-      (make-styled-paragraph (list (make-element "refcontent"
-                                                 c))
-                             "refpara")))
+                                         ".")))))
 
   (define (refsecref s)
     (make-element #f (list (secref s) " in " MzScheme))))

collects/scribblings/guide/guide.scrbl

@@ -28,6 +28,8 @@ precise details to @|MzScheme| and other reference manuals.
 
 @include-section["forms.scrbl"]
 
+@include-section["module-basics.scrbl"]
+
 @; ----------------------------------------------------------------------
 @section[#:tag "contracts"]{Contracts}
 

collects/scribblings/guide/keywords.scrbl

@@ -6,19 +6,27 @@
 @title[#:tag "keywords"]{Keywords}
 
 A @defterm{keyword} is similar to a symbol (see @secref["symbols"]),
-but its printed form is prefixed with @schemefont{#:}. Unlike a
-symbol, it's printed form is also its expression form.
+but its printed form is prefixed with @schemefont{#:}.
 
 @refdetails["mz:parse-keyword"]{the syntax of keywords}
 
 @examples[
 (string->keyword "apple")
-#:apple
-(eq? #:apple (string->keyword "apple"))
+'#:apple
+(eq? '#:apple (string->keyword "apple"))
 ]
 
-Although keywords are values, they are intented for use as special
-markers in argument lists and in certain syntactic forms.
+Although keywords are values, an unquoted keyword is not an
+expression, just as an unquoted identifier does not produce a symbol:
+
+@examples[
+not-a-symbol-expression
+#:not-a-keyword-expression
+]
+
+Despite their similarities, keywords are used differently than
+symbols. Keywords are intented for use (unquoted) as special markers
+in argument lists and in certain syntactic forms.
 
 @italic{Need some examples here, once we have more keyword-based
 procedures and syntax in place...}

collects/scribblings/guide/lambda.scrbl

@@ -0,0 +1,159 @@
+#reader(lib "docreader.ss" "scribble")
+@require[(lib "manual.ss" "scribble")]
+@require[(lib "eval.ss" "scribble")]
+@require["guide-utils.ss"]
+
+@title[#:tag "guide:lambda"]{Procedures}
+
+A @scheme[lambda] expression creates a procedure. In the simplest
+case, a @scheme[lambda] expression has the form
+
+@specform[
+(lambda (arg-id ...)
+  body-expr ...+)
+]
+
+The @scheme[...+] in this syntactic sketch means ``one or more
+repetitions of the preceeding element;'' that is, one or more
+@scheme[_body-expr]s.
+
+A @scheme[lambda] form with @math{n} @scheme[_arg-id]s accepts
+@math{n} arguments:
+
+@interaction[
+((lambda (x) x)
+ 1)
+((lambda (x y) (+ x y)) 
+ 1 2)
+((lambda (x y) (+ x y)) 
+ 1)
+]
+
+A @scheme[lambda] expression can also have the form
+
+@specform[
+(lambda rest-id
+  body-expr ...+)
+]
+
+That is, a @scheme[lambda] expression can have a single
+@scheme[_rest-id] that is not surrounded by parentheses. The resulting
+procedure accepts any number of arguments, and the arguments are put
+into a list bound to @scheme[_rest-id].
+
+@examples[
+((lambda x x) 
+ 1 2 3)
+((lambda x x))
+((lambda x (car x))
+ 1 2 3)
+]
+
+Combining thes two styles, a @scheme[lambda] expression can have the
+form
+
+@specform[
+(lambda (arg-id ...+ . rest-id)
+  body-expr ...+)
+]
+
+The result is a procedure that requires at least as many arguments as
+@scheme[_arg-id]s, and also accepts any number of additional
+arguments.
+
+@examples[
+((lambda (a b . x) (cons (/ a b) x))
+ 1 2 3 4)
+((lambda (a b . x) (cons (/ a b) x))
+ 1 2)
+((lambda (a b . x) (cons (/ a b) x)) 
+ 1)
+]
+
+Support for optional and keyword arguments lead to even more
+possibilities:
+
+@itemize{
+
+ @item{Instead of just an @scheme[_arg-id], an form argument can be
+       @scheme[[_arg-id _default-expr]], which means that the argument
+       is optional. When the argument is not supplied,
+       @scheme[_default-expr] produces the default value. The
+       @scheme[_default-expr] can refer to any preceding
+       @scheme[_arg-id], and every following @scheme[_arg-id] must
+       have a default as well.
+
+       @examples[
+         ((lambda (x [y 5]) (list x y))
+          1 2)
+         ((lambda (x [y 5]) (list x y)) 
+          1)
+         ((lambda (x [y (+ x 1)]) (list x y))
+          1)
+         (lambda ([x 5] y) (list x y))
+       ]}
+
+ @item{Instead of just an @scheme[_arg-id], an form argument can be
+       @scheme[(code:line _keyword _arg-id)], which indicates a
+       by-keyword argument instead of a by-position argument. The
+       position of the keyword--identifier pair in the argument list
+       does not matter for matching with arguments in an application,
+       because it will be matched to an argument value by keyword
+       insteda of by position.
+
+       @examples[
+         ((lambda (x #:second y) (list x y))
+          1 #:second 2)
+         ((lambda (x #:second y) (list x y)) 
+          #:second 2 1)
+         ((lambda (#:second y x) (list x y)) 
+          1 #:second 2)
+         ((lambda (x #:second y) (list x y)) 
+          1 2)
+         ((lambda (x #:second y) (list x y))
+          #:second 2)
+       ]}
+
+ @item{The previous two possibilities can be combined to specify a
+       by-keyword argument with a default value.
+
+       @examples[
+         ((lambda (x #:second [y 5]) (list x y))
+          1 #:second 2)
+         ((lambda (x #:second [y 5]) (list x y))
+          1)
+       ]}
+
+}
+
+The @scheme[case-lambda] form creates a procedure that can have
+completely different behaviors depending on the number of arguments
+that are supplied. A case-lambda expression has the form
+
+@specform[
+(case-lambda
+  [formals body-expr ...+]
+  ...)
+]
+
+where each @scheme[_formals _body-expr ...+] is anlogous to
+@scheme[(lambda _formals _body-expr ...+)]. That is, a
+@scheme[_formals] can be @scheme[(_arg-id ...)], @scheme[_rest-id], or 
+@scheme[(_arg-id ... . _rest-id)].
+
+Applying a procedure produced by @scheme[case-lambda] is like applying
+a @scheme[lambda] for the first case that matches the number of given
+arguments.
+
+@examples[
+((case-lambda [() 10][(x y) (+ x y)])
+ 1 2)
+((case-lambda [() 10][(x y) (+ x y)]))
+((case-lambda [() 10][(x y) (+ x y)])
+ 1)
+]
+
+A @scheme[case-lambda] procedure cannot directly support optional or
+keyword arguments.
+
+@refdetails["mz:lambda"]{procedure expressions}

collects/scribblings/guide/lists.scrbl

@@ -189,7 +189,7 @@ simpler (just a procedure call).
 We have ignored several other variants of the interation
 form---including plain @scheme[for], which is used when the iteration
 body is to be run only for its effect. For more complete information,
-see @secref["for"].
+see @secref["guide:for"].
 
 @;------------------------------------------------------------------------
 @section{List Iteration from Scratch}

collects/scribblings/guide/module-basics.scrbl

@@ -3,4 +3,51 @@
 @require[(lib "eval.ss" "scribble")]
 @require["guide-utils.ss"]
 
-@title{Module Basics}
+@title{Modules}
+
+Scheme definitions and expressions are normally written inside of a
+module. Although a REPL evaluates definitions and expressions outide
+of a module, and although @scheme[load] can evaluate definitions and
+expressions from a file as if they appeared in a REPL interaction,
+code that is meant to last for more than a few seconds belongs in a
+module.
+
+The space of modules is distinct from the space of normal Scheme
+definitions. Since modules typically reside in files, the space of
+module names is explicitly tied to the filesystem at run time. For
+example, if the file @file{/home/molly/cake.ss} contains
+
+@schememod[
+big
+
+(provide print-cake)
+
+(code:comment #, @t{draws a cake with @scheme[n] candles})
+(define (print-cake n)
+  (printf "   ~a  \n" (make-string n #\.))
+  (printf " .-~a-.\n" (make-string n #\|))
+  (printf " | ~a |\n" (make-string n #\space))
+  (printf "---~a---\n" (make-string n #\-)))
+]
+
+then it can be used as the source of a module whose full name is based
+on the path @file{/home/molly/cake.ss}. Instead of using the full
+path, however, the module is likely to be referenced by a releative
+path. For example, a file @file{/home/molly/random-cake.ss} could use
+the module like this:
+
+@schememod[
+big
+
+(require "cake.ss")
+
+(print-cake (random 30))
+]
+
+The relative reference @scheme[(require "cake.ss")] works because the
+@file{cake.ss} module source is in the same directory as the
+@file{random-cake.ss} file.
+
+As you see in the above examples, @scheme[provide] and
+@scheme[require] are module-level declarations that export and import
+bindings between modules.

collects/scribblings/guide/symbols.scrbl

@@ -3,7 +3,7 @@
 @require[(lib "eval.ss" "scribble")]
 @require["guide-utils.ss"]
 
-@title{Symbols}
+@title[#:tag "symbols"]{Symbols}
 
 A @defterm{symbol} is an atomic value that prints like an identifier.
 An expression that starts with @litchar{'} and continues with an

collects/scribblings/guide/to-scheme.scrbl

@@ -12,6 +12,6 @@ skip to @secref["datatypes"].
 @local-table-of-contents[]
 
 @include-section["simple-data.scrbl"]
-@include-section["syntax.scrbl"]
+@include-section["simple-syntax.scrbl"]
 @include-section["lists.scrbl"]
 @include-section["truth.scrbl"]

collects/scribblings/guide/void-and-undef.scrbl

@@ -29,8 +29,8 @@ initialized. Such early references are not possible for bindings that
 corerspond to procedure arguments, @scheme[let] bindings, or
 @scheme[let*] bindings; early reference requires a recursive binding
 context, such as @scheme[letrec] or local @scheme[define]s in a
-procedure body. Also, early references to top-level and module
-top-level bindings raise an exception, instead of producing
+procedure body. Also, early references to top-level and module-level
+bindings raise an exception, instead of producing
 @|undefined-const|. For these reasons, @undefined-const rarely
 appears.
 

collects/scribblings/reference/derived.scrbl

@@ -3,7 +3,9 @@
 
 @title[#:tag "mz:derived-syntax"]{Derived Syntactic Forms}
 
-@section{Iterations and Comprehensions: @scheme[for], @scheme[for/list], ...}
+@section[#:tag "mz:for"]{Iterations and Comprehensions: @scheme[for], @scheme[for/list], ...}
+
+@guideintro["guide:for"]{iterations and comprehensions}
 
 @defform[(for (for-clause ...) . body)]{
 

collects/scribblings/reference/model.scrbl

@@ -137,7 +137,7 @@ each of its sub-expression. In addtion, some procedures (notably
 a certain number of values.
 
 @;------------------------------------------------------------------------
-@section{Top-level and Module Bindings}
+@section{Top-Level and Module-Level Bindings}
 
 Given
 
@@ -187,7 +187,7 @@ right-hand expression must be reduced to a value.
 ]
 
 Most definitions in PLT Scheme are in modules. In terms of evaluation,
-a module is simply a prefix on a defined name, so that different
+a module is essentially a prefix on a defined name, so that different
 modules can define the name.
 
 Using @scheme[set!], a program can change the value associated with an
@@ -476,7 +476,13 @@ location.
 An @defterm{identifier} is source-program entity. Parsing a Scheme
 program reveals that some identifiers correspond to variables, some
 refer to syntactic forms, and some are quoted to produce a symbol or a
-syntax object.
+syntax object. An identifier @scheme[binds] another when the former is
+parsed as a variable and the latter is parsed as a reference to the
+former. An identifier is @scheme[bound] in a sub-expression if it
+binds any uses of the identifier in the sub-expression that are not
+otherwise bound within the sub-expression; conversely, a binding for a
+sub-expression @defterm{shadows} any bindings in its context, so that
+uses of an identifier refer to the shaodowing binding.
 
 Throughout the documentation, identifiers are typeset to suggest the
 way that they are parsed. A black, boldface identifier like

collects/scribblings/reference/mz.ss

@@ -1,7 +1,9 @@
 (module mz mzscheme
   (require (lib "struct.ss" "scribble")
            (lib "manual.ss" "scribble")
-           (lib "eval.ss" "scribble"))
+           (lib "eval.ss" "scribble")
+           (lib "decode.ss" "scribble")
+           (lib "kw.ss"))
 
   (provide (all-from (lib "manual.ss" "scribble"))
            (all-from (lib "eval.ss" "scribble")))
@@ -14,4 +16,19 @@
   (define-syntax Exn
     (syntax-rules ()
       [(_ s) (scheme s)]))
-  (provide exnraise Exn))
+  (provide exnraise Exn)
+
+  (provide Guide guideintro)
+
+  (define Guide
+    (italic (link "../guide/index.html" "A Guide to PLT Scheme")))
+
+  (define/kw (guideintro tag #:body s)
+    (apply margin-note
+           (decode-content (append (list "For an introduction to ")
+                                   s
+                                   (list ", see "
+                                         (secref tag)
+                                         " in "
+                                         Guide
+                                         "."))))))

collects/scribblings/reference/syntax.scrbl

@@ -63,7 +63,7 @@ the reference evaluates to the value in the location associated with
 the binding.
 
 When the expander encounters an @scheme[id] that is not bound by a
-module or local binding, it converts the expression to @scheme[(#,
+module-level or local binding, it converts the expression to @scheme[(#,
 @schemeidfont{#%top} . id)] giving @schemeidfont{#%top} the lexical
 context of the @scheme[id]; typically, that context refers to
 @scheme[#%top].
@@ -87,7 +87,9 @@ references are disallowed anywhere within a @scheme[module] form.
 ]}
 
 @;------------------------------------------------------------------------
-@section{Procedure Applications and @scheme[#%app]}
+@section[#:tag "mz:application"]{Procedure Applications and @scheme[#%app]}
+
+@guideintro["guide:application"]{procedure applications}
 
 @defform/none[(proc-expr arg ...)]{
 
@@ -146,7 +148,9 @@ according to their order in the application form.
 
 
 @;------------------------------------------------------------------------
-@section{Procedure Expressions: @scheme[lambda] and @scheme[case-lambda]}
+@section[#:tag "mz:lambda"]{Procedure Expressions: @scheme[lambda] and @scheme[case-lambda]}
+
+@guideintro["guide:lambda"]{procedure expressions}
 
 @defform[(lambda formals* . body)]{
 
@@ -314,8 +318,9 @@ within @scheme[body] to the procedure itself.}
 
 Similar to @scheme[let], but evaluates the @scheme[val-expr]s one by
 one, creating a location for each @scheme[id] as soon as the value is
-available, and binding @scheme[id] in the remaining @scheme[val-expr]s
-as well as the @scheme[body]. The @scheme[id]s need not be distinct.
+availablek. The @scheme[id]s are bound in the remaining @scheme[val-expr]s
+as well as the @scheme[body], and the @scheme[id]s need not be
+distinct.
 
 @examples[
 (let ([x 1]