boost::urls::grammar::not_empty_rule :: Boost Libraries Documentation

# boost::urls::grammar::not_empty_rule

Match another rule, if the result is not empty

## Synopsis

Declared in `<boost/url/grammar/not_empty_rule.hpp>`

    template<Rule R>
    constexpr
    /* implementation-defined */
    not_empty_rule(R const& r);

## Description

This adapts another rule such that when an empty string is successfully parsed, the result is an error.

## Value Type

    using value_type = typename Rule::value_type;

## Example

Rules are used with the function `parse`.

    system::result< decode_view > rv = parse( "Program%20Files",
        not_empty_rule( pct_encoded_rule( unreserved_chars ) ) );

## Return Value

The adapted rule

## Parameters

Name | Description
--- | ---
r | The rule to match

## See Also

`parse`, `pct_encoded_rule`, `unreserved_chars`.

Created with MrDocs