instead of a closed set of languages. I also removed the offsets:
I simply use the current region to determine whether the
preprocessing directie starts at the beginning of a line. I also
removed scanning line indicators, to make the lexer simpler.
like the absence of an input filename. (This simplifies all the
clients codes.) Fixed the dune file for the preprocessor. Fixed
the build of PreprocMain.exe and PreprocMain.byte. Restricted
preprocessing errors [Preproc.Newline_in_string] and
[Preproc.Open_string] to the argument of the #include
directive (instead of general strings: this is for the LIGO lexer
to report the error). I removed the error [Preproc.Open_comment]
as this is for the LIGO lexer to report. The preprocessor scanner
[Preproc.lex] does not take a parameter [is_file:bool] now: the
source file (if any) is determined from the lexing
buffer. Accordingly, the field [is_file] of the state of the
preprocessing lexer has been removed: the lexing buffer becomes
now the reference for the input source (bug fix and interface
improvement). Fixed the comments of the test contract
pledge.religo. I removed the data constructor [Lexer.Stdin], as
redundant with [Lexer.Channel].
