armarx::skills::client::result_handling_policies Namespace Reference

Result handling policies. More...

Classes
class	Continue
	Ignore any skill outcome and just continue. More...
class	Escalate
	Escalate any failures by throwing an exception. More...
class	WarnOnFailureAndContinue
	Print a warning on failure but continue in any case. More...

Detailed Description

Result handling policies.

These policies are meant to be used to handle common use-cases in handling outputs of skill executions to avoid boilerplate. Since the skill outputs should be std::expected and expected is defined as [[nodiscard]], unhandled outputs will result in compiler warnings. Thus, to get rid of the warnings, the output must be stored in a local variable and handled as such:

auto result = skill({.params = …});
if (result != Success)
{
    <handling the error or ignoring the error or printing it or ...>
}

The purpose of these policies is to allow skill business object authors to define operators to handle common use-cases in a one liner. Specifically, by overwriting operator||() and the given policy as parameter as follows:

void operator||(std::expected<Skill:Output, Skill::ErrorOutput> const& skillResult,
                armarx::skills::client::result_handling_policies::Continue const& policy)
{
    // Silently ignore any outcome.
}

a fluent skill execution can be written that handles the outcome as follows:

using namespace armarx::skills::client::result_handling_policies; // Pull the policies into
the current scope.
 
skill({.params = …}) or Continue();  // This will handle the outcome and supress the warning.

The currently supported policies are defined in this namespace. The skill business object author is responsible for supplying these overloads if they want to support this feature.