text_parser 0.0.1

A Dart package for parsing text flexibly according to preset or custom regular expression patterns.

text_parser

A Dart package for parsing text flexibly according to preset or custom regular expression patterns.

Usage

Using preset matchers (URL / email address / phone number)

If matchers is omitted in TextParser, the three preset matchers (UrlMatcher, EmailMatcher and TelMatcher) are used automatically.

The default regular expression pattern of each of them is not very strict. If it is unsuitable for your use case, overwrite the pattern by yourself, referring to the description in a later section of this document.

import 'package:text_parser/text_parser.dart';

Future<void> main() async {
  final parser = TextParser();
  final elements = await parser.parse(
    'abc https://example.com/sample.jpg. def\n'
    '[e-mail] [phone]',
  );
  elements.forEach(print);
}

Output:

matcherType: TextMatcher, text: abc , groups: []
matcherType: UrlMatcher, text: https://example.com/sample.jpg, groups: []
matcherType: TextMatcher, text: . def\n, groups: []
matcherType: EmailMatcher, text: [e-mail], groups: []
matcherType: TextMatcher, text:  , groups: []
matcherType: TelMatcher, text: [phone], groups: []

Overwriting the pattern of a preset matcher

If you want to parse only URLs and phone numbers, but treat only a sequence of eleven numbers after tel: as a phone number:

final parser = TextParser(
  matchers: const [
    UrlMatcher(),
    TelMatcher(r'(?<=tel:)\d{11}'),
  ],
);

If the match patterns of multiple matchers have matched the same string at the same position in text, the first matcher is used for parsing the element.

Using a custom matcher

You can create a custom matcher easily by extending TextMatcher. The following is a matcher for links of the Markdown format like [text](link_such_as_url_or_path).

class MdLinkMatcher extends TextMatcher {
  const MdLinkMatcher() : super(r'\[(.+?)\]\((.+?)\)');
}

...

final parser = TextParser(
  matchers: const [MdLinkMatcher()],
);
final elements = await parser.parse('abcde[foo](bar)fghij');
elements.forEach(print);

Output:

matcherType: TextMatcher, text: abcde, groups: []
matcherType: MdLinkMatcher, text: [foo](bar), groups: [foo, bar]
matcherType: TextMatcher, text: fghij, groups: []

Groups

Each TextElement in a parse result has the property of groups. It is an array of strings that have matched the smaller pattern inside each set of parentheses ( ).

To give the above code as an example, there are two sets of parentheses in the above example; (.+?) in \[(.+?)\] and \((.+?)\). They match foo and bar respectively, so they are added to the array in that order.

Tip:

If you want certain parentheses to be not captured as a group, add ?: after the starting parenthesis, like (?:pattern).

Limitations

• Parsing is not executed in an isolate but in the main thread on the web, which dart:isolate does not support.
• It may take seconds to parse a very long string with complicated matchers as this package uses RegExp.