state_wrapper< TagT, StateT, DataT > Struct Template Reference

A decorator for the accumulator of a reduction. More...

#include <atria/xform/state_wrapper.hpp>

Public Types
using	tag = TagT
using	base_t = std::tuple< StateT, DataT >

Public Member Functions
	state_wrapper (const state_wrapper &)=default
	state_wrapper (state_wrapper &&)=default
state_wrapper &	operator= (const state_wrapper &)=default
state_wrapper &	operator= (state_wrapper &&)=default
template<typename T , typename U >
	state_wrapper (T &&st, U &&data)

Detailed Description

template<typename TagT = no_tag, typename StateT = void, typename DataT = void>
struct atria::xform::state_wrapper< TagT, StateT, DataT >

A decorator for the accumulator of a reduction.

A transducer must not make any assumptions about the accumulator of the process it is helping to reduce. However, a stateful transducer may use a state_wrapper to attach extra data to the accumulator such that the reducing function object itself can be state-less.

A state wrapper has the following template arguments:

Template Parameters

TagT	is as tag type used to identify the transducer that is attaching the state. This can useful to specialize the state_traits for a concrete state wrapper.
StateT	is the accumulator that is to be wrapped and of which we shall make no assumptions.
DataT	is the additional data that the transducer wants to attach to represent its own state.

For an example of a stateful reducing function,

See also

take

wrap_state

state_traits

Definition at line 69 of file state_wrapper.hpp.

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The documentation for this struct was generated from the following file:

• src/atria/xform/state_wrapper.hpp