[format.formattable]

# 28 Text processing library [[text]](./#text)

## 28.5 Formatting [[format]](format#formattable)

### 28.5.6 Formatter [[format.formatter]](format.formatter#format.formattable)

#### 28.5.6.3 Concept formattable [format.formattable]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/text.tex#L7097)

Let *fmt-iter-for*<charT> be an unspecified type
that models[output_iterator](iterator.concept.output#concept:output_iterator "24.3.4.10 Concept output_­iterator [iterator.concept.output]")<const charT&> ([[iterator.concept.output]](iterator.concept.output "24.3.4.10 Concept output_­iterator"))[.](#1.sentence-1)

template<class T, class Context, class Formatter = typename Context::template formatter_type<remove_const_t<T>>>concept [*formattable-with*](#concept:formattable-with "28.5.6.3 Concept formattable [format.formattable]") = // *exposition only*[semiregular](concepts.object#concept:semiregular "18.6 Object concepts [concepts.object]")<Formatter> &&requires(Formatter& f, const Formatter& cf, T&& t, Context fc,
 basic_format_parse_context<typename Context::char_type> pc){{ f.parse(pc) } -> [same_as](concept.same#concept:same_as "18.4.2 Concept same_­as [concept.same]")<typename decltype(pc)::iterator>; { cf.format(t, fc) } -> [same_as](concept.same#concept:same_as "18.4.2 Concept same_­as [concept.same]")<typename Context::iterator>; };

template<class T, class charT>concept [formattable](#concept:formattable "28.5.6.3 Concept formattable [format.formattable]") =[*formattable-with*](#concept:formattable-with "28.5.6.3 Concept formattable [format.formattable]")<remove_reference_t<T>, basic_format_context<*fmt-iter-for*<charT>, charT>>;

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/text.tex#L7119)

A type T and a character type charT model [formattable](#concept:formattable "28.5.6.3 Concept formattable [format.formattable]") if formatter<remove_cvref_t<T>, charT> meets
the *BasicFormatter* requirements ([[formatter.requirements]](formatter.requirements "28.5.6.1 Formatter requirements"))
and, if remove_reference_t<T> is const-qualified,
the *Formatter* requirements[.](#2.sentence-1)