(CODING_SYSTEM_P): If ID is not available, call

Fcoding_system_p.
(CHECK_CODING_SYSTEM): If ID is not available, call
Fcheck_coding_system.
(CHECK_CODING_SYSTEM_GET_SPEC): Try also Fcheck_coding_system.
(CHECK_CODING_SYSTEM_GET_ID): Likewise.

1 files changed, 16 insertions, 3 deletions

diff --git a/src/coding.h b/src/coding.h
index 834724cf340..89ceb7cad3b 100644
--- a/src/coding.h
+++ b/src/coding.h
@@ -212,14 +212,17 @@ enum coding_attr_index
 
 /* Return 1 iff CODING_SYSTEM_SYMBOL is a coding system.  */
 
-#define CODING_SYSTEM_P(coding_system_symbol)   \
-  (! NILP (CODING_SYSTEM_SPEC (coding_system_symbol)))
+#define CODING_SYSTEM_P(coding_system_symbol)           \
+  (CODING_SYSTEM_ID (coding_system_symbol) >= 0         \
+   || (! NILP (coding_system_symbol)                    \
+       && ! NILP (Fcoding_system_p (coding_system_symbol))))
 
 /* Check if X is a coding system or not.  */
 
 #define CHECK_CODING_SYSTEM(x)                          \
   do {                                                  \
-    if (!CODING_SYSTEM_P (x))                           \
+    if (CODING_SYSTEM_ID (x) < 0                        \
+        && NILP (Fcheck_coding_system (x)))             \
       wrong_type_argument (Qcoding_system_p, (x));      \
   } while (0)
 
@@ -231,6 +234,11 @@ enum coding_attr_index
   do {                                                  \
     spec = CODING_SYSTEM_SPEC (x);                      \
     if (NILP (spec))                                    \
+      {                                                 \
+        Fcheck_coding_system (x);                       \
+        spec = CODING_SYSTEM_SPEC (x);                  \
+      }                                                 \
+    if (NILP (spec))                                    \
       x = wrong_type_argument (Qcoding_system_p, (x));  \
   } while (0)
 
@@ -243,6 +251,11 @@ enum coding_attr_index
     {                                                           \
       id = CODING_SYSTEM_ID (x);                                \
       if (id < 0)                                               \
+        {                                                       \
+          Fcheck_coding_system (x);                             \
+          id = CODING_SYSTEM_ID (x);                            \
+        }                                                       \
+      if (id < 0)                                               \
         x = wrong_type_argument (Qcoding_system_p, (x));        \
     } while (0)