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grammar::lut_chars::lut_chars (3 of 3 overloads)

Constructor.

Synopsis
template<
    class Pred>
constexpr
lut_chars(
    Pred const& pred);
Description

This function constructs a character set which has as members, every value of char ch for which the expression pred(ch) returns true.

Example
struct is_digit
{
    constexpr bool
    operator()(char c ) const noexcept
    {
        return c >= '0' && c <= '9';
    }
};

constexpr lut_chars digits( is_digit{} );
Complexity

Linear in pred, or constant if pred(ch) is a constant expression.

Exception Safety

Throws nothing.

Parameters

Name

Description

pred

The function object to use for determining membership in the character set.


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