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digitalmars.D.learn - hyperlink regular expression pattern

reply John C <johnch_atms hotmail.com> writes:
I want to split an HTML anchor tag into its constituent parts. I have a regular
expression pattern that works with .NET's Regex class, but not with std.regexp
- it errors out with "*+? not allowed in atom". I think this means something in
the pattern is non-standard.

Here's my code:

if (auto m = std.regexp.search(
  "<a href=\"www.google.com\">Google</a>", 
  r"<a.*?href=[""'](?<url>.*?)[""'].*?>(?<name>.*?)</a>")) {
  string url = m.match(1);
  string name = m.match(2);
}

The problematic parts are "?<url>" and "?<name>" - but not being a whiz with
regular expressions, I don't know what to use instead.

Perhaps someone's got a better pattern they could post?

John.
May 09 2008
parent reply novice2 <sorry noem.ail> writes:
 Perhaps someone's got a better pattern they could post?

this works for me (dmd 1.029) import std.regexp; void main() { if (auto m = std.regexp.search( "<a href=\"www.google.com:8080/dfs?a1=1&a2=2\">This is Google link</a>", "<a[^>]+href=(['\"]?)(.*?)\\1.*?>(.*)</a>")) { for(int i=0; i<10; i++) { printf("%d=\"%.*s\"\n", i, m.match(i)); } } }
May 09 2008
parent reply John C <johnch_atms hotmail.com> writes:
novice2 Wrote:

 Perhaps someone's got a better pattern they could post?

this works for me (dmd 1.029) import std.regexp; void main() { if (auto m = std.regexp.search( "<a href=\"www.google.com:8080/dfs?a1=1&a2=2\">This is Google link</a>", "<a[^>]+href=(['\"]?)(.*?)\\1.*?>(.*)</a>")) { for(int i=0; i<10; i++) { printf("%d=\"%.*s\"\n", i, m.match(i)); } } }

Thanks - that seems to extract the href and text. What about getting other attributes like name and title, as in this link: <a href=\"www.google.com\" name=\"googleLink\" title=\"Click Me\">Google Link</a>
May 09 2008
parent novice2 <sorry noem.ail> writes:
John C Wrote:

 Thanks - that seems to extract the href and text.

what you asked - that you got :) "question is half of answer" :)
What about getting other attributes like name and title, as in this link:
 
 <a href=\"www.google.com\" name=\"googleLink\" title=\"Click Me\">Google
Link</a>

imho, it can't be done by one regexp match. because of random sequense of attributes. imho, you should get whole <a> tag attributes string, then iterate attributes in it. something like this below. but sorry, it can't catch attributes without quotes. may be, std.strings non-regexp will be better when parsing attributes. ////// import std.regexp; import std.stdio; void main() { if (auto m = std.regexp.search("<anothertag><a href=\"www.google.com:8080/dfs?a1=1&a2=2\" name='google Link' color=red title=\"Click Me\"\">This is Google link</a></anothertag>", "<a(\\s.*?)>(.*?)</a>")) { writefln("tag attributes: \"%s\"", m.match(1)); writefln("tag content: \"%s\"", m.match(2)); foreach(s; RegExp("(\\S+?)=(['\"]?)(.*?)\\2").search(m.match(1))) { writefln("found attribute: name=\"%s\", value=\"%s\"", s.match(1), s.match(3)); } } }
May 09 2008