val initial_state : state
Initial state of the preprocessor.
update st name lnum line takes as input the state
st of the preprocessor, the file name
name, the number of the next input line
lnum and the next input line
line itself. It returns a tuple of the new state, the new file name, the new line number, and a boolean. The new file name and line number can be used to implement line number directives. The boolean is
true if the line should be part of the input (i.e. it is not a specific preprocessor line) and
false if it should be ignored. The function may raise
Preprocessor_error in case of error.
val check_final : state -> string -> unit
check_final st name check that
st indeed is a correct state of the preprocessor for the end of input of file
name. If it is not the case, then the exception
Preprocessor_error is raised.