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digitalmars.D.learn - forcing tabs in regex

reply dark777 <jeanzonta777 yahoo.com.br> writes:
Regex validates years bisexto and not bisextos in format:
const std::regex 
pattern(R"(^(?:(?:(0?[1-9]|1\d|2[0-8])([-/.])(0?[1-9]|1[0-2]|[Jj](?:an|u[nl])|[Mm]a[ry]|[Aa](?:pr|ug)|[Ss]ep|[Oo]ct|[Nn]ov|[Dd]ec|[Ff]eb)|(29|30)([-/.])(0?[13-9]|1[0-2]|[Jj](?:an|u[nl])|[Mm]a[ry]|[Aa](?:pr|ug)|[Ss]ep|[Oo]ct|[Nn]ov|[Dd]ec)|(31)([-/.])(0?[13578]|1[02]|[Jj]an|[Mm]a[ry]|[Jj]ul|[Aa]ug|[Oo]ct|[Dd]ec))(?:\2|\5|\8)(0{2,3}[1-9]|0{1,2}[1-9]\d|0?[1-9]\d{2}|[1-9]\d{3})|(29)([-/.])(0?2|[Ff]eb)\12(\d{1,2}(?:0[48]|[2468][048]|[13579][26])|(?:0?[48]|[13579][26]|[2468][048])00))$)");

this regex above validates the formats through backreferences.

dd-mm-yyyy ou dd-str-yyyy ou dd-Str-yyyy
dd/mm/yyyy ou dd/str/yyyy ou dd/Str/yyyy
dd.mm.yyyy ou dd.str.yyyy ou dd.Str.yyyy



Regex validates years bisexto and not bisextos in format:
const std::regex 
pattern(R"(^(?:\d{4}([-/.])(?:(?:(?:(?:0?[13578]|1[02]|[Jj](?:an|ul)|[Mm]a[ry]|[Aa]ug|[Oo]ct|[Dd]ec)([-/.])(?:0?[1-9]|[1-2][0-9]|3[01]))|(?:(?:0?[469]|11|[Aa]pr|[Jj]un|[Ss]ep|[Nn]ov)([-/.])(?:0?[1-9]|[1-2][0-9]|30))|(?:(0?2|[Ff]eb)([-/.])(?:0?[1-9]|1[0-9]|2[0-8]))))|(?:(?:\d{2}(?:0[48]|[2468][048]|[13579][26]))|(?:(?:[02468][048])|[13579][26])00)([-/.])(0?2|[Ff]eb)([-/.])29)$)");

this regex above had to validate the formats through 
backreferences.

but it is validating in the following formats
yyyy-mm/dd ou yyyy-str/dd ou yyyy-Str/dd
yyyy/mm.dd ou yyyy/str.dd ou yyyy/Str.dd
yyyy.mm-dd ou yyyy.str-dd ou yyyy.Str-dd


when it had to validate only in the following formats
yyyy-mm-dd ou yyyy-str-dd ou yyyy-Str-dd
yyyy/mm/dd ou yyyy/str/dd ou yyyy/Str/dd
yyyy.mm.dd ou yyyy.str.dd ou yyyy.Str.dd

how do I do it validate only with some of the tabs?
Feb 27 2018
parent reply psychoticRabbit <meagain meagain.com> writes:
On Wednesday, 28 February 2018 at 01:06:30 UTC, dark777 wrote:

 Regex validates years bisexto and not bisextos in format:
 const std::regex 
 pattern(R"(^(?:(?:(0?[1-9]|1\d|2[0-8])([-/.])(0?[1-9]|1[0-2]|[Jj](?:an|u[nl])|[Mm]a[ry]|[Aa](?:pr|ug)|[Ss]ep|[Oo]ct|[Nn]ov|[Dd]ec|[Ff]eb)|(29|30)([-/.])(0?[13-9]|1[0-2]|[Jj](?:an|u[nl])|[Mm]a[ry]|[Aa](?:pr|ug)|[Ss]ep|[Oo]ct|[Nn]ov|[Dd]ec)|(31)([-/.])(0?[13578]|1[02]|[Jj]an|[Mm]a[ry]|[Jj]ul|[Aa]ug|[Oo]ct|[Dd]ec))(?:\2|\5|\8)(0{2,3}[1-9]|0{1,2}[1-9]\d|0?[1-9]\d{2}|[1-9]\d{3})|(29)([-/.])(0?2|[Ff]eb)\12(\d{1,2}(?:0[48]|[2468][048]|[13579][26])|(?:0?[48]|[13579][26]|[2468][048])00))$)");

 this regex above validates the formats through backreferences.


what is this evil dark magic?
Feb 27 2018
parent Dmitry Olshansky <dmitry.olsh gmail.com> writes:
On Wednesday, 28 February 2018 at 05:09:03 UTC, psychoticRabbit 
wrote:

 On Wednesday, 28 February 2018 at 01:06:30 UTC, dark777 wrote:

 Regex validates years bisexto and not bisextos in format:
 const std::regex 
 pattern(R"(^(?:(?:(0?[1-9]|1\d|2[0-8])([-/.])(0?[1-9]|1[0-2]|[Jj](?:an|u[nl])|[Mm]a[ry]|[Aa](?:pr|ug)|[Ss]ep|[Oo]ct|[Nn]ov|[Dd]ec|[Ff]eb)|(29|30)([-/.])(0?[13-9]|1[0-2]|[Jj](?:an|u[nl])|[Mm]a[ry]|[Aa](?:pr|ug)|[Ss]ep|[Oo]ct|[Nn]ov|[Dd]ec)|(31)([-/.])(0?[13578]|1[02]|[Jj]an|[Mm]a[ry]|[Jj]ul|[Aa]ug|[Oo]ct|[Dd]ec))(?:\2|\5|\8)(0{2,3}[1-9]|0{1,2}[1-9]\d|0?[1-9]\d{2}|[1-9]\d{3})|(29)([-/.])(0?2|[Ff]eb)\12(\d{1,2}(?:0[48]|[2468][048]|[13579][26])|(?:0?[48]|[13579][26]|[2468][048])00))$)");

 this regex above validates the formats through backreferences.


 what is this evil dark magic?


Something that is horribly slow and might be incorrect, there are 
very few reasons to write large regexes like that and they 
usually boil down to “it only accepts regex” otherwise parser 
combinators are much better fit.
Feb 27 2018