Text lines are usually terminated with LF (\n, the POSIX+Unix+Linux+MacOS+default-Cygwin way) or CR LF (\r\n, the CP/M+MS-DOS+Windows way). Others exist, and I've tried to accomodate them, but I think we should remove support for "reversed" LF CR line endings in the spec.
Background: Nobody officially uses LF CR as a line ending, but sometimes people screw up and generate reversed LF CR line-endings. An EOL detector can, after reading an LF, peek to see if the next char is a CR (and if so consume that too), and thus be generous in what it accepts. Sadly this can make interactive use annoying in guile, because of a longstanding bug in guile. In guile, a "peek-char" actually *CONSUMES* an EOF, instead of just reporting it. Yes, that's in violation of the Scheme R5RS, and probably most/all Scheme specs, but there it is. This means that in interactive use, if you press "ENTER control-D" on POSIX system, a routine that peeks for CR will consume the EOF (ugh). Working around that is a pain, you have to pass that EOF info all the way up, and I don't see that it's worth it. An LF CR is just too uncommon, and arguably a bug. I don't mind supporting bare CR as end-of-line; that would generally be data files, not interactive use, and guile works fine with file EOF (guile just keeps regenerating EOF at the end of a real file). Bare CR used to be used by many systems, including the Commodore 64, Apple II, and MacOS up to version 9, so there are still a few files that use it, and I don't see the harm in supporting it. I plan to also support IBM NEL. --- David A. Wheeler ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ Readable-discuss mailing list Readable-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/readable-discuss
