Replace C++ (in)equality checks with proper SCM syntax

This commit replaces the most straightforward situations
where two SCM objects are compared.  Here are the basic
replacements used:

x == y                  ------->            scm_is_eq (x,y)
x == SCM_BOOL_T         ------->            to_boolean (x)
x == SCM_BOOL_F         ------->            scm_is_false (x)
x != SCM_BOOL_T         ------->            scm_is_true (x)
x == SCM_UNDEFINED      ------->            SCM_UNBNDP (x)
x == SCM_EOL            ------->            scm_is_null (x)
(scm_exact_p (x) == SCM_BOOL_T)  ------->   ly_is_rational (x)
(scm_integer_p (x) == SCM_BOOL_T) ------->  scm_is_integer (x)
(scm_list_p (x) == SCM_BOOL_T)  ------->    ly_is_list (x)
(scm_port_p (x) == SCM_BOOL_T)  ------->    ly_is_port (x)
(scm_equal_p (x, y) == SCM_BOOL_T) -------> ly_is_equal (x,y)

Finally, I replaced (!cached) with (!SCM_UNPACK (cached)) in
lily-guile-macros.hh, as has been suggested once by David.

Please note that this commit does not handle some situations
I’m less comfortable with (namely those involving scm_c_memq,
scm_assq or scm_hashq_get_handle), and some scm_*_p checks
for which there isn’t a ly_is_* replacement yet (to wit,
scm_hash_table_p, scm_promise_p, and scm_variable_bound_p).
Those should be dealt with later (another patch is in the works).

1 files changed, 7 insertions, 6 deletions

diff --git a/lily/dynamic-engraver.cc b/lily/dynamic-engraver.cc
index 8be008f8fb..0bbe69f075 100644
--- a/lily/dynamic-engraver.cc
+++ b/lily/dynamic-engraver.cc
@@ -107,7 +107,7 @@ Dynamic_engraver::get_property_setting (Stream_event *evt,
                                         char const *ctxprop)
 {
   SCM spanner_type = evt->get_property (evprop);
-  if (spanner_type == SCM_EOL)
+  if (scm_is_null (spanner_type))
     spanner_type = get_property (ctxprop);
   return spanner_type;
 }
@@ -141,7 +141,7 @@ Dynamic_engraver::process_music ()
       SCM cresc_type = get_property_setting (current_span_event_, "span-type",
                                              (start_type + "Spanner").c_str ());
 
-      if (cresc_type == ly_symbol2scm ("text"))
+      if (scm_is_eq (cresc_type, ly_symbol2scm ("text")))
         {
           current_spanner_
             = make_spanner ("DynamicTextSpanner",
@@ -156,12 +156,13 @@ Dynamic_engraver::process_music ()
             early: this allows dynamics to be spaced individually instead of
             being linked together.
           */
-          if (current_spanner_->get_property ("style") == ly_symbol2scm ("none"))
+          if (scm_is_eq (current_spanner_->get_property ("style"),
+                         ly_symbol2scm ("none")))
             current_spanner_->set_property ("spanner-broken", SCM_BOOL_T);
         }
       else
         {
-          if (cresc_type != ly_symbol2scm ("hairpin"))
+          if (!scm_is_eq (cresc_type, ly_symbol2scm ("hairpin")))
             {
               string as_string = ly_scm_write_string (cresc_type);
               current_span_event_
@@ -244,9 +245,9 @@ Dynamic_engraver::get_spanner_type (Stream_event *ev)
   string type;
   SCM start_sym = scm_car (ev->get_property ("class"));
 
-  if (start_sym == ly_symbol2scm ("decrescendo-event"))
+  if (scm_is_eq (start_sym, ly_symbol2scm ("decrescendo-event")))
     type = "decrescendo";
-  else if (start_sym == ly_symbol2scm ("crescendo-event"))
+  else if (scm_is_eq (start_sym, ly_symbol2scm ("crescendo-event")))
     type = "crescendo";
   else
     programming_error ("unknown dynamic spanner type");