From 5884bb1a494854431cb7f083f30c97b3336fa65b Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Thu, 20 Aug 2015 07:17:50 -0700
Subject: [PATCH] small clarifications; add `here-key-path`

---
 doclang-raw.rkt         |  2 +-
 reader-base.rkt         | 16 +++++++++-------
 scribblings/world.scrbl |  4 +++-
 template.rkt            |  2 +-
 world.rkt               |  4 +++-
 5 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/doclang-raw.rkt b/doclang-raw.rkt
index 97ec97a..b4f203b 100755
--- a/doclang-raw.rkt
+++ b/doclang-raw.rkt
@@ -11,7 +11,7 @@
 (define-syntax (*module-begin stx)
   (syntax-case stx ()
     [(_ . body)
-     (with-syntax ([id #'doc-raw]
+     (with-syntax ([id #'doc-raw] ; name of the main export from doclang-raw
                    [post-process #'(λ(x) x)]
                    [exprs #'()])
        #'(#%module-begin
diff --git a/reader-base.rkt b/reader-base.rkt
index 846ff6c..acd3fad 100644
--- a/reader-base.rkt
+++ b/reader-base.rkt
@@ -9,7 +9,8 @@
 
 
 (define (split-metas tree)
-  (define (meta-matcher x) (and (pair? x) (eq? (car x) (world:current-define-meta-name))))
+  (define (meta-matcher x) ; meta has form (define-meta key value)
+    (and (list? x) (>= (length x) 3) (eq? (first x) (world:current-define-meta-name))))
   (define matches empty)
   (define rest
     (let loop ([x tree])
@@ -22,7 +23,8 @@
          (set! matches (append new-matches matches))
          (map loop rest)]
         [else x])))
-  (values matches rest))
+  (let ([meta-key second][meta-value third])
+    (values (map meta-key matches) (map meta-value matches) rest)))
 
 
 (define (make-custom-read-syntax reader-mode)
@@ -36,7 +38,7 @@
                         #:syntax? #t 
                         #:inside? #t))
     (define source-stx (read-inner path-string p))
-    (define-values (meta-matches meta-free-file-data) (split-metas (syntax->datum source-stx)))
+    (define-values (meta-keys meta-values meta-free-file-data) (split-metas (syntax->datum source-stx)))
     (define reader-here-path (cond
                                [(symbol? path-string) (symbol->string path-string)]
                                [(equal? path-string "unsaved editor") path-string]
@@ -51,10 +53,10 @@
                                                          [else world:mode-preproc])])
                               auto-computed-mode)
                             reader-mode))
-    (define meta-keys (cons 'here-path (map second meta-matches)))
-    (define meta-values (cons reader-here-path (map third meta-matches)))
-    (with-syntax ([(KEY ...) (datum->syntax source-stx meta-keys)]
-                  [(VALUE ...) (datum->syntax source-stx meta-values)])
+    (define meta-keys-plus-here (cons (world:current-here-path-key) meta-keys)) ; here-path at front so it can be overridden
+    (define meta-values-plus-here (cons reader-here-path meta-values))
+    (with-syntax ([(KEY ...) (datum->syntax source-stx meta-keys-plus-here)]
+                  [(VALUE ...) (datum->syntax source-stx meta-values-plus-here)])
       (syntax-property
        (replace-context source-stx
                         #`(module runtime-wrapper racket/base
diff --git a/scribblings/world.scrbl b/scribblings/world.scrbl
index b800d35..4e7e543 100644
--- a/scribblings/world.scrbl
+++ b/scribblings/world.scrbl
@@ -131,4 +131,6 @@ Default separators used in decoding. The first two are initialized to @racket["\
 
 @defoverridable[compile-cache-max-size exact-positive-integer?]{Maximum size of the compile cache. Default is 10 megabytes.}
 
-@defoverridable[unpublished-path? (path? . -> . boolean?)]{Predicate that determines whether a path is omitted from @secref{raco_pollen_publish} operations. If the predicate is @racket[#t], then the path is omitted. The default, therefore, is @racket[#f].}
\ No newline at end of file
+@defoverridable[unpublished-path? (path? . -> . boolean?)]{Predicate that determines whether a path is omitted from @secref{raco_pollen_publish} operations. If the predicate is @racket[#t], then the path is omitted. The default, therefore, is @racket[#f].}
+
+@defoverridable[here-path-key symbol?]{Key used to store the absolute path of the current source file in its @racket[metas] hashtable. Default is @racket['here-path].}
\ No newline at end of file
diff --git a/template.rkt b/template.rkt
index ef04dcd..d75f8d4 100644
--- a/template.rkt
+++ b/template.rkt
@@ -8,7 +8,7 @@
 
 (define/contract+provide (metas->here metas)
   (hash? . -> . pagenode?)
-  (path->pagenode (or (select-from-metas 'here-path metas) 'unknown)))
+  (path->pagenode (or (select-from-metas (world:current-here-path-key) metas) 'unknown)))
 
 
 (define (pagenode->path pagenode)
diff --git a/world.rkt b/world.rkt
index 72ec08f..d310476 100644
--- a/world.rkt
+++ b/world.rkt
@@ -89,4 +89,6 @@
 (define-settable compile-cache-active #t)
 (define-settable compile-cache-max-size (* 10 1024 1024)) ; = 10 megabytes
 
-(define-settable unpublished-path? (λ(path) #f))
\ No newline at end of file
+(define-settable unpublished-path? (λ(path) #f))
+
+(define-settable here-path-key 'here-path)
\ No newline at end of file