On Mon, Oct 15, 2018 at 9:33 AM Michael Van Canneyt <mich...@freepascal.org> wrote: > > > On Sun, Oct 14, 2018 at 8:19 PM Michael Van Canneyt > > <mich...@freepascal.org> wrote: > >> > >> > >> > >> On Mon, 15 Oct 2018, Sven Barth via fpc-pascal wrote: > >> > >> > Marcos Douglas B. Santos <m...@delfire.net> schrieb am So., 14. Okt. > >> 2018, > >> > 16:15: > >> > > >> >> Do you know any Pascal lib to parse strings to convert in date/time > >> values? > >> >> The user is supposed to type human-friendly values like: > >> >> - "day" => trunc(now) > >> >> - "day-2" => trunc(now-2) > >> >> - "week" => trunc(now-7) > >> >> - "yesterday" => trunc(now-1) > >> >> - etc... > >> >> But they could type even their computer date format or ISO as well. > >> >> > >> >> A lib in C, but very complex: > >> >> - https://github.com/gagern/gnulib/blob/master/lib/parse-datetime.y > >> >> > >> >> I would like to start with something simpler, if possible. Thank you. > >> >> > >> > > >> > I don't know a specific library that fulfills your needs, but maybe > >> you can > >> > build something atop of FpExprPars: > >> > http://wiki.lazarus.freepascal.org/How_To_Use_TFPExpressionParser > >> > At least according to the source it also supports datetime handling. > > > > Thanks, Sven. > > > >> > >> It does, it's used (amongst other things) in the reporting engine; > > > > Michael, > > But does it work using just date values - accordingly with date format > > in OS - or also with "day", "tomorrow", etc? > > If not, can I extend those classes without change the original ones? > > All depends on the exact format you want to use. > day -1 > can be easily implemented by registering a function day, which returns teh > same Date()
So I can register those identifiers as functions, cool! > double quotes are supported as delimiters for identifiers, so "Day" should > work, but a date literal is going to be tricky. Maybe I can test the value first if it is a valid date format, before try to use FpExprPars on it... It looks like a good start, though. Thanks. regards, Marcos Douglas _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
