Effects

Effect builders let a generator-based or asynchronous workflow stop as soon as an Option is absent or a Result is an error. Prefer ordinary map and bind for short workflows; see Use effect builders for an example.

A collection of computational expression effects.

async_option

alias of AsyncOptionBuilder

async_result

alias of AsyncResultBuilder

async_try

alias of AsyncTryBuilder

option

alias of OptionBuilder

result

alias of ResultBuilder

seq

alias of SeqBuilder

try_

alias of TryBuilder

class Builder

Effect builder.

bind(xs: _M, fn: Callable[[_T], _M]) → _M

combine(xs: _M, ys: _M) → _M

Used for combining multiple statements in the effect.

delay(fn: Callable[[], _M]) → _M

Delay the computation.

Default implementation is to return the result of the function.

return_(x: _T) → _M

return_from(xs: _M) → _M

run(computation: _M) → _M

Run a computation.

Default implementation is to return the computation as is.

zero() → _M

Zero effect.

Called if the effect raises StopIteration without a value, i.e returns None.

class BuilderState

Encapsulates the state of a builder computation.