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	Updated documentation about stringifying UDTs
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		| @@ -1,7 +1,7 @@ | ||||
| # String conversions | ||||
|  | ||||
| Catch needs to be able to convert types you use in assertions and logging expressions into strings (for logging and reporting purposes). | ||||
| Most built-in or std types are supported out of the box but there are three ways that you can tell Catch how to convert your own types (or other, third-party types) into strings. | ||||
| Most built-in or std types are supported out of the box but there are two ways that you can tell Catch how to convert your own types (or other, third-party types) into strings. | ||||
|  | ||||
| ## operator << overload for std::ostream | ||||
|  | ||||
| @@ -16,42 +16,19 @@ std::ostream& operator << ( std::ostream& os, T const& value ) { | ||||
|  | ||||
| (where ```T``` is your type and ```convertMyTypeToString``` is where you'll write whatever code is necessary to make your type printable - it doesn't have to be in another function). | ||||
|  | ||||
| You should put this function in the same namespace as your type. | ||||
|  | ||||
| Alternatively you may prefer to write it as a member function: | ||||
|  | ||||
| ``` | ||||
| std::ostream& T::operator << ( std::ostream& os ) const { | ||||
| 	os << convertMyTypeToString( *this ); | ||||
| 	return os; | ||||
| } | ||||
| ``` | ||||
|  | ||||
| ## Catch::toString overload | ||||
|  | ||||
| If you don't want to provide an ```operator <<``` overload, or you want to convert your type differently for testing purposes, you can provide an overload for ```Catch::toString()``` for your type. | ||||
|  | ||||
| ``` | ||||
| namespace Catch { | ||||
| 	std::string toString( T const& value ) { | ||||
| 		return convertMyTypeToString( value ); | ||||
| 	} | ||||
| } | ||||
| ``` | ||||
|  | ||||
| Again ```T``` is your type and ```convertMyTypeToString``` is where you'll write whatever code is necessary to make your type printable. Note that the function must be in the Catch namespace, which itself must be in the global namespace. | ||||
| You should put this function in the same namespace as your type and have it declared before including Catch's header. | ||||
|  | ||||
| ## Catch::StringMaker<T> specialisation | ||||
|  | ||||
| There are some cases where overloading toString does not work as expected. Specialising StringMaker<T> gives you more precise, and reliable, control - but at the cost of slightly more code and complexity: | ||||
| If you don't want to provide an ```operator <<``` overload, or you want to convert your type differently for testing purposes, you can provide a specialization for `Catch::StringMaker<T>`: | ||||
|  | ||||
| ``` | ||||
| namespace Catch { | ||||
| 	template<> struct StringMaker<T> { | ||||
|     	static std::string convert( T const& value ) { | ||||
|         	return convertMyTypeToString( value );  | ||||
|         }  | ||||
|     };  | ||||
| 	template<> | ||||
|     struct StringMaker<T> { | ||||
|     	std::string operator()( T const& value ) { | ||||
|         	return convertMyTypeToString( value ); | ||||
|         } | ||||
|     }; | ||||
| } | ||||
| ``` | ||||
|  | ||||
|   | ||||
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	 Martin Hořeňovský
					Martin Hořeňovský