X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Funpure-pure-container.cc;h=143b2fd47de4c118e4b1818e94a9bc8c4779e01a;hb=97a0169312a260933246ab224e4f8b0969871dd5;hp=d5962bd028d29f9014e0ca612fa28bb5a44f67ab;hpb=958e95822083954cad00e0a598eb9f12ceba67b9;p=lilypond.git

diff --git a/lily/unpure-pure-container.cc b/lily/unpure-pure-container.cc
index d5962bd028..143b2fd47d 100644
--- a/lily/unpure-pure-container.cc
+++ b/lily/unpure-pure-container.cc
@@ -19,19 +19,21 @@
 */
 #include "unpure-pure-container.hh"
 
-// Reroutes a call to the contained function after dropping last two
-// arguments.  Used for applying an "unpure" function in a "pure"
+// Reroutes a call to the contained function after dropping second and
+// third argument.  Used for applying an "unpure" function in a "pure"
 // context.
 class Unpure_pure_call : public Smob1<Unpure_pure_call>
 {
 public:
+  // Smob procedures unfortunately can only take at most 3 SCM
+  // arguments.  Otherwise we could use a "3, 0, 1" call signature and
+  // not require an argument count check of our own.
   LY_DECLARE_SMOB_PROC (&Unpure_pure_call::call, 2, 0, 1)
-  SCM call (SCM arg1, SCM arg2, SCM rest)
+  SCM call (SCM arg1, SCM, SCM rest)
   {
-    return scm_apply_0 (scm1 (),
-                        scm_call_2 (ly_lily_module_constant ("drop-right"),
-                                    scm_cons2 (arg1, arg2, rest),
-                                    scm_from_int (2)));
+    if (!scm_is_pair (rest))
+      scm_wrong_num_args (scm1 ());
+    return scm_apply_1 (scm1 (), arg1, scm_cdr (rest));
   }
 };
 
@@ -43,7 +45,7 @@ Unpure_pure_container::pure_part () const
     : scm2 ();
 }
 
-const char Unpure_pure_container::type_p_name_[] = "ly:unpure-pure-container?";
+const char * const Unpure_pure_container::type_p_name_ = "ly:unpure-pure-container?";
 
 LY_DEFINE (ly_make_unpure_pure_container, "ly:make-unpure-pure-container",
            1, 1, 0, (SCM unpure, SCM pure),
@@ -73,7 +75,7 @@ LY_DEFINE (ly_unpure_pure_container_pure_part, "ly:unpure-pure-container-pure-pa
 }
 
 int
-Unpure_pure_container::print_smob (SCM port, scm_print_state *)
+Unpure_pure_container::print_smob (SCM port, scm_print_state *) const
 {
   scm_puts ("#<unpure-pure-container ", port);
   scm_display (unpure_part (), port);
@@ -85,3 +87,40 @@ Unpure_pure_container::print_smob (SCM port, scm_print_state *)
   scm_puts (" >", port);
   return 1;
 }
+
+LY_DEFINE (ly_pure_call, "ly:pure-call",
+           4, 0, 1, (SCM data, SCM grob, SCM start, SCM end, SCM rest),
+           "Convert property @var{data} (unpure-pure container or procedure)"
+           " to value in a pure context defined by @var{grob},"
+           " @var{start}, @var{end}, and possibly @var{rest} arguments.")
+{
+  if (Unpure_pure_container *upc = unsmob<Unpure_pure_container> (data))
+    {
+      // Avoid gratuitous creation of an Unpure_pure_call
+      if (upc->is_unchanging ())
+        data = upc->unpure_part ();
+      else
+        {
+          data = upc->pure_part ();
+          if (ly_is_procedure (data))
+            return scm_apply_3 (data, grob, start, end, rest);
+          return data;
+        }
+    }
+  if (ly_is_procedure (data))
+    return scm_apply_1 (data, grob, rest);
+  return data;
+}
+
+LY_DEFINE (ly_unpure_call, "ly:unpure-call",
+           2, 0, 1, (SCM data, SCM grob, SCM rest),
+           "Convert property @var{data} (unpure-pure container or procedure)"
+           " to value in an unpure context defined by @var{grob}"
+           " and possibly @var{rest} arguments.")
+{
+  if (Unpure_pure_container *upc = unsmob<Unpure_pure_container> (data))
+    data = upc->unpure_part ();
+  if (ly_is_procedure (data))
+    return scm_apply_1 (data, grob, rest);
+  return data;
+}