BB.MCP.ParameterValue (bb_mcp v0.3.2)

Translate parameter values across the MCP boundary.

Most parameter types are JSON scalars already, but a {:unit, _} parameter holds a Localize.Unit struct, which JSON.encode!/1 cannot encode. Unit values travel as a tagged object carrying the magnitude and the CLDR unit name:

%{"value" => -12.5, "unit" => "degree"}

The tag makes the value self-describing, so a client can write back exactly what it read from list_parameters, get_parameter or the parameters resource without having to interpret the declared type. Writes also accept a bare number for a unit-typed parameter, which is given the unit declared in the robot's parameter schema.

Summary

Functions

deserialise(robot, path, magnitude)

Rebuild a parameter value from the JSON a client sent, ready for BB.Parameter.set/3.

serialise(value)

Render a parameter value as a term JSON.encode!/1 can carry.

Functions

deserialise(robot, path, magnitude)

@spec deserialise(module(), [atom()], term()) :: {:ok, term()} | {:error, String.t()}

Rebuild a parameter value from the JSON a client sent, ready for BB.Parameter.set/3.

Returns {:error, message} when a tagged object names a unit which cannot be parsed.

serialise(value)

@spec serialise(term()) :: term()

Render a parameter value as a term JSON.encode!/1 can carry.