Updated documentation for unstable/srcloc; added it for unstable/location.

svn: r18010

collects/unstable/scribblings/srcloc.scrbl

@@ -1,10 +1,27 @@
 #lang scribble/manual
 @(require scribble/eval "utils.ss" (for-label scheme/base unstable/srcloc))
 
-@(define evaluator (make-base-eval))
+@(define unsyntax #f)
-@(evaluator '(require unstable/srcloc))
 
-@title[#:tag "srcloc"]{Source Locations}
+@(define (new-evaluator)
+   (let* ([e (make-base-eval)])
+     (e '(require (for-syntax scheme/base)
+                  unstable/srcloc
+                  unstable/location))
+     e))
+
+@(define evaluator (new-evaluator))
+
+@(define reference-path
+   '(lib "scribblings/reference/reference.scrbl"))
+
+@title{Source Locations}
+
+There are two libraries in this collection for dealing with source locations;
+one for manipulating representations of them, and the other for quoting the
+location of a particular piece of source code.
+
+@section[#:tag "srcloc"]{Representations}
 
 @defmodule[unstable/srcloc]
 
@@ -96,6 +113,62 @@ span sources.  They also convert the result to the desired representation:
 
 }
 
+@defproc[(source-location-known? [loc source-location?]) boolean?]{
+
+This predicate reports whether a given source location contains more information
+than simply @scheme[#f].
+
+@examples[#:eval evaluator
+(source-location-known? #f)
+(source-location-known? (make-srcloc #f #f #f #f #f))
+(source-location-known? (make-srcloc 'source 1 2 3 4))
+(source-location-known? (list #f #f #f #f #f))
+(source-location-known? (vector 'source #f #f #f #f))
+(source-location-known? (datum->syntax #f null #f))
+(source-location-known? (datum->syntax #f null (list 'source #f #f #f #f)))
+]
+
+}
+
+@deftogether[(
+@defproc[(source-location-source [loc source-location?]) any/c]
+@defproc[(source-location-line [loc source-location?])
+         (or/c orexact-positive-integer? #f)]
+@defproc[(source-location-column [loc source-location?])
+         (or/c exact-nonnegative-integer? #f)]
+@defproc[(source-location-position [loc source-location?])
+         (or/c exact-positive-integer? #f)]
+@defproc[(source-location-span [loc source-location?])
+         (or/c exact-nonnegative-integer? #f)]
+)]{
+
+These accessors extract the fields of a source location.
+
+@examples[#:eval evaluator
+(source-location-source #f)
+(source-location-line (make-srcloc 'source 1 2 3 4))
+(source-location-column (list 'source 1 2 3 4))
+(source-location-position (vector 'source 1 2 3 4))
+(source-location-span (datum->syntax #f null (list 'source 1 2 3 4)))
+]
+
+}
+
+@defproc[(source-location-end [loc source-location?])
+         (or/c exact-nonnegative-integer? #f)]{
+
+This accessor produces the end position of a source location (the sum of its
+position and span, if both are numbers) or @scheme[#f].
+
+@examples[#:eval evaluator
+(source-location-end #f)
+(source-location-end (make-srcloc 'source 1 2 3 4))
+(source-location-end (list 'source 1 2 3 #f))
+(source-location-end (vector 'source 1 2 #f 4))
+]
+
+}
+
 @deftogether[(
 @defproc[(source-location->string [loc source-location?]) string?]{}
 @defproc[(source-location->prefix [loc source-location?]) string?]{}
@@ -121,3 +194,143 @@ The first produces a string describing the source location; the second appends
 ]
 
 }
+
+@section[#:tag "location"]{Quoting}
+
+@defmodule[unstable/location]
+
+@unstable[@author+email["Carl Eastlund" "cce@ccs.neu.edu"]]
+
+This module defines macros that evaluate to various aspects of their own source
+location.
+
+@emph{Note:} The examples below illustrate the use of these macros and the
+representation of their output.  However, due to the mechanism by which they are
+generated, each example is considered a single character and thus does not have
+realistic line, column, and character positions.
+
+Furthermore, the examples illustrate the use of source location quoting inside
+macros, and the difference between quoting the source location of the macro
+definition itself and quoting the source location of the macro's arguments.
+
+@defform*[[(quote-srcloc) (quote-srcloc expr)]]{
+
+This form quotes the source location of @scheme[expr] as a @scheme[srcloc]
+structure, using the location of the whole @scheme[(quote-srcloc)] expression if
+no @scheme[expr] is given.
+
+@defexamples[#:eval (new-evaluator)
+(quote-srcloc)
+(define-syntax (not-here stx) #'(quote-srcloc))
+(not-here)
+(not-here)
+(define-syntax (here stx) #`(quote-srcloc #,stx))
+(here)
+(here)
+]
+
+}
+
+@deftogether[(
+@defform*[[(quote-source-file) (quote-source-file expr)]]
+@defform*[[(quote-line-number) (quote-line-number expr)]]
+@defform*[[(quote-column-number) (quote-column-number expr)]]
+@defform*[[(quote-character-position) (quote-character-position expr)]]
+@defform*[[(quote-character-span) (quote-character-span expr)]]
+)]{
+
+These forms quote various fields of the source location of @scheme[expr], or of
+the whole macro application if no @scheme[expr] is given.
+
+@examples[#:eval (new-evaluator)
+(list (quote-source-file)
+      (quote-line-number)
+      (quote-column-number)
+      (quote-character-position)
+      (quote-character-span))
+(define-syntax (not-here stx)
+  #'(list (quote-source-file)
+          (quote-line-number)
+          (quote-column-number)
+          (quote-character-position)
+          (quote-character-span)))
+(not-here)
+(not-here)
+(define-syntax (here stx)
+  #`(list (quote-source-file #,stx)
+          (quote-line-number #,stx)
+          (quote-column-number #,stx)
+          (quote-character-position #,stx)
+          (quote-character-span #,stx)))
+(here)
+(here)
+]
+
+}
+
+@defform[(quote-module-path)]{
+
+This form quotes a module path suitable for use with @scheme[require] which
+refers to the module in which the macro application occurs.  If executed at the
+top level, it may return @scheme['top-level], or it may return a valid module
+path if the current namespace was constructed by @scheme[module->namespace]
+(such as at the DrScheme interactions window).
+
+This macro operates by creating a @tech[#:doc reference-path]{variable
+reference} (see @scheme[#%variable-reference]) at the point of its application.
+It thus automatically describes its final expanded position, rather than the
+module of any macro definition that happens to use it.
+
+@defexamples[#:eval (new-evaluator)
+(quote-module-path)
+(module A scheme
+  (require unstable/location)
+  (define-syntax-rule (here) (quote-module-path))
+  (define a (here))
+  (provide a here))
+(require 'A)
+a
+(module B scheme
+  (require unstable/location)
+  (require 'A)
+  (define b (here))
+  (provide b))
+(require 'B)
+b
+[current-namespace (module->namespace (quote 'A))]
+(quote-module-path)
+]
+
+}
+
+@defform[(quote-module-name)]{
+
+This form quotes the name (@tech[#:doc reference-path]{path} or @tech[#:doc
+reference-path]{symbol}) of the module in which the macro application occurs, or
+@scheme[#f] if it occurs at the top level.  As with @scheme[quote-module-path],
+@scheme[quote-module-name] uses a @tech[#:doc reference-path]{variable
+reference}, so a top level namespace created by @scheme[module->namespace] will
+be treated as a module, and the macro will always produce the module name of its
+final expanded position.
+
+@defexamples[#:eval (new-evaluator)
+(quote-module-name)
+(module A scheme
+  (require unstable/location)
+  (define-syntax-rule (here) (quote-module-name))
+  (define a (here))
+  (provide a here))
+(require 'A)
+a
+(module B scheme
+  (require unstable/location)
+  (require 'A)
+  (define b (here))
+  (provide b))
+(require 'B)
+b
+[current-namespace (module->namespace (quote 'A))]
+(quote-module-name)
+]
+
+}