Returns language settings obtained from a request map.

Returns an ID (a keyword) of a default language set in config (under the :default key) or a value of the default-fallback-language variable (:en).

Forces different language in a request map by setting :language/id and :language/str.

Reads a language from the given request map by getting a value specified by a sequence of keys, converting the result to a keyword and checking against a set of supported languages.

Returns a value associated with :param key in settings obtained from a request map or a config. If it does not exist or has falsy value, default-lang-param is returned.

Picks the right language using a chain of picking functions identified by a keyword. In its unary variant it obtains language picker chains configuration from a request map (under :language/pickers key) and looks for the picker chain identified by the :default key. When it’s not nil, it is used.

In its binary variant it takes a request map and pickers configuration given as a map OR a request map and an ID of a picker given as a keyword. When a map is given, the picker chain associated with the :default key will be used. When a picker ID is given the chain will be selected from picker chains obtained from the req under the key :language/pickers. Next, the picker chain will be run with a request map as its argument and the result will be then returned.

In its ternary variant the given pickers map will be used to look for a chain under the given picker-id. This chain will be run with a request map as its argument to get the language.

If the value returned by a language picker chain will be nil or false then the default language will be returned (if configured).

The same as pick but returns nil instead of a default language when pickers cannot get one.

Returns configured pickers map obtained from a request.

Prepares a single picker. If it is a map, :compile key should be associated with a function which will return a language-picking function. Symbol may be given and it will be resolved. The compiling function should take a single argument which is a middleware configuration. All keys of the map except :handler and :compile will be passed to it.

If :handler is specified in a map, it should be a function or a symbol which resolves to a function.

If the p is not a map, it should be a function.

A function returned by the compiling function, given as :handler, or simply assigned should take one argument, a request map, and return a language identifier as a keyword.

When a language-picking function is created on a basis of a map (specified by :handler or :compile) then it has the responsibility of transforming its result to a keyword and checking if the chosen language identifier belongs to a supported languages expressed in a configuration as a set under the :supported key. Note that picker compiling function will receive configuration under the config key and should generate a function which takes a single argument (request map) whereas handler should take two arguments, the first being a configuration.

When a language-picking function is not a map but a function (or a symbolic, resolvable identifier of a function) then it will be wrapped in another function and its result will be converted to a keyword and tested against existence in the aforementioned set of supported languages.

Returns a value associated with :supported key in settings obtained from a request map or a config.

Language wrapping middleware.