keymap: Do not use vim_isIDc in keymap.c

Note: there are three changes to ascii_isident. Reverting first two (in 
find_special_key and first in get_special_key_code) normally fails the new test 
with empty &isident, but reverting the third does not. Hence adding `>` to 
&isident.

Ref vim/vim#2389.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/nvim/ascii.h b/src/nvim/ascii.h
index adde91f9ec..9ccb70764d 100644
--- a/src/nvim/ascii.h
+++ b/src/nvim/ascii.h
@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 
+#include "nvim/macros.h"
 #include "nvim/func_attr.h"
 #include "nvim/os/os_defs.h"
 
@@ -98,6 +99,10 @@ static inline bool ascii_isxdigit(int)
   REAL_FATTR_CONST
   REAL_FATTR_ALWAYS_INLINE;
 
+static inline bool ascii_isident(int)
+  REAL_FATTR_CONST
+  REAL_FATTR_ALWAYS_INLINE;
+
 static inline bool ascii_isbdigit(int)
   REAL_FATTR_CONST
   REAL_FATTR_ALWAYS_INLINE;
@@ -138,6 +143,14 @@ static inline bool ascii_isxdigit(int c)
          || (c >= 'A' && c <= 'F');
 }
 
+/// Checks if `c` is an “identifier” character
+///
+/// That is, whether it is alphanumeric character or underscore.
+static inline bool ascii_isident(const int c)
+{
+  return ASCII_ISALNUM(c) || c == '_';
+}
+
 /// Checks if `c` is a binary digit, that is, 0-1.
 ///
 /// @see {ascii_isdigit}