[PATCH 1/5] Remove parser/location global variable setup

[David Kastrup]

Instead of relying on the global parser/location work horse (or
respective symbols in local scope), now fluids %parser/%location and
getter functions (*parser*)/(*location*) are employed for setting up the
general parsing and providing #{...#} with accurate information.

This patch removes the global setup and internal information flow: there
is still a variable "parser" being set in local parser modules.
---
 lily/parse-scm.cc             | 16 +++++++++++-----
 ly/init.ly                    | 17 ++++++++---------
 scm/lily.scm                  | 15 +++++++++++++++
 scm/parser-ly-from-scheme.scm |  4 ++--
 4 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/lily/parse-scm.cc b/lily/parse-scm.cc
index ec0c157..08c67cc 100644
--- a/lily/parse-scm.cc
+++ b/lily/parse-scm.cc
@@ -146,15 +146,15 @@ protected_ly_parse_scm (Parse_start *ps)
 }
 
 SCM
-protected_ly_eval_scm (Parse_start *ps)
+protected_ly_eval_scm (void *ps)
 {
   /*
     Catch #t : catch all Scheme level errors.
    */
   return scm_internal_catch (SCM_BOOL_T,
                              catch_protected_eval_body,
-                             (void *) ps,
-                             &parse_handler, (void *) ps);
+                             ps,
+                             &parse_handler, ps);
 }
 
 bool parse_protect_global = true;
@@ -178,8 +178,14 @@ ly_eval_scm (SCM form, Input i, bool safe, Lily_parser 
*parser)
 {
   Parse_start ps (form, i, safe, parser);
 
-  SCM ans = parse_protect_global ? protected_ly_eval_scm (&ps)
-            : internal_ly_eval_scm (&ps);
+  SCM ans = scm_c_with_fluids
+    (scm_list_2 (ly_lily_module_constant ("%parser"),
+                 ly_lily_module_constant ("%location")),
+     scm_list_2 (parser->self_scm (),
+                 i.smobbed_copy ()),
+     parse_protect_global ? protected_ly_eval_scm
+     : catch_protected_eval_body, (void *) &ps);
+
   scm_remember_upto_here_1 (form);
   return ans;
 }
diff --git a/ly/init.ly b/ly/init.ly
index d014a40..5075d71 100644
--- a/ly/init.ly
+++ b/ly/init.ly
@@ -17,12 +17,11 @@
    ;; function has not actually started.  A parser clone, in contrast,
    ;; can run and complete synchronously and shares the module with
    ;; the current parser.
-   (ly:parser-parse-string (ly:parser-clone parser)
+   (ly:parser-parse-string (ly:parser-clone (*parser*))
     "\\include \"declarations-init.ly\"")))
 
-#(note-names-language parser default-language)
+#(note-names-language (*parser*) default-language)
 
-#(define location #f)
 #(define toplevel-scores (list))
 #(define toplevel-bookparts (list))
 #(define $defaultheader #f)
@@ -38,7 +37,7 @@
 #(use-modules (ice-9 pretty-print))
 
 $(if (ly:get-option 'include-settings)
-  (ly:parser-include-string parser
+  (ly:parser-include-string (*parser*)
     (format #f "\\include \"~a\"" (ly:get-option 'include-settings))))
 
 \maininput
@@ -69,14 +68,14 @@ $(if (ly:get-option 'include-settings)
                             (ly:book-add-score! book score))
                           (reverse! toplevel-scores)))
             (set! toplevel-scores (list))
-            (book-handler parser book)))
+            (book-handler (*parser*) book)))
          ((or (pair? toplevel-scores) output-empty-score-list)
           (let ((book (apply ly:make-book $defaultpaper
                              $defaultheader toplevel-scores)))
             (set! toplevel-scores (list))
-            (book-handler parser book)))))
+            (book-handler (*parser*) book)))))
 
-#(if (eq? expect-error (ly:parser-has-error? parser))
-  (ly:parser-clear-error parser)
+#(if (eq? expect-error (ly:parser-has-error? (*parser*)))
+  (ly:parser-clear-error (*parser*))
   (if expect-error
-   (ly:parser-error parser (_ "expected error, but none found"))))
+   (ly:parser-error (*parser*) (_ "expected error, but none found"))))
diff --git a/scm/lily.scm b/scm/lily.scm
index 27ba76a..b2283e5 100644
--- a/scm/lily.scm
+++ b/scm/lily.scm
@@ -43,6 +43,21 @@
    (string-downcase
     (car (string-tokenize (utsname:sysname (uname)) char-set:letter)))))
 
+;; We don't use (srfi srfi-39) (parameter objects) here because that
+;; does not give us a name/handle to the underlying fluids themselves.
+
+(define %parser (make-fluid))
+(define %location (make-fluid))
+;; No public setters: should not get overwritten in action
+(define-public (*parser*) (fluid-ref %parser))
+(define-public (*location*) (fluid-ref %location))
+
+;; It would be nice to convert occurences of parser/location to
+;; (*parser*)/(*location*) using the syncase module but it is utterly
+;; broken in GUILE 1 and would require changing a lot of unrelated
+;; innocuous constructs which just happen to fall apart with
+;; inscrutable error messages.
+
 ;;
 ;; Session-handling variables and procedures.
 ;;
diff --git a/scm/parser-ly-from-scheme.scm b/scm/parser-ly-from-scheme.scm
index dd3e698..7322d9b 100644
--- a/scm/parser-ly-from-scheme.scm
+++ b/scm/parser-ly-from-scheme.scm
@@ -74,8 +74,8 @@ from @var{port} and return the corresponding Scheme music 
expression.
             (ly:parser-error parser (_ "error in #{ ... #}")))
         result))
     (list embedded-lilypond
-          'parser lily-string filename line
+          (list *parser*) lily-string filename line
           (cons 'list (reverse! closures))
-          'location)))
+          (list *location*))))
 
 (read-hash-extend #\{ read-lily-expression)
-- 
2.1.4