+There is one special input method file "global.mim" that declares
+common variables and commands. The input method driver always loads
+this file and other input methods can inherit the variables and the
+commands.
+
+@c VARIABLE-DECLARATION declares a variable used in this input method.
+If a variable must be initialized to the default value, or is to be
+customized by a user, it must be declared here. The declaration can
+be used in two ways. One is to introduce a new variable. In that
+case, @c VALUE must not be omitted. Another is to inherit the variable
+from what declared in "global.mim", and to give the different default
+value and/or to make the variable customizable specially for the
+current input method. In the latter case, @c VALUE can be omitted.
+
+@c COMMAND-DECLARATION declares a command used in this input method.
+If a command must be bound to the default key sequence, or is to be
+customized by a user, it must be declared here. Like @c
+VARIABLE-DECLARATION, the declaration can be used in two ways. One is
+to introduce a new command. In that case, @c KEYSEQ must not be omitted.
+Another is to inherit the command from what declared in "global.mim",
+and to give the different key binding and/or to make the command
+customizable specially for the current input method. In the latter
+case, @c KEYSEQ can be omitted.