in src/composer/composer.py [0:0]
def when(test, consequent, alternate):
return composer.let(
{ 'params': None },
set_params,
composer.ensure(
set_params,
composer.when_nosave(
composer.mask(test),
composer.ensure(get_params, composer.mask(consequent)),
composer.ensure(get_params, composer.mask(alternate)))))