deferred_command.bend

bendvy-ecs-core@0.1.0.3 · 16 lines · 4 definitions

1import Base
2import bendvy-ecs-core@0.1.0.3/trace_facts.bend as Facts
3
4# Each staged command owns its payload once. Trusted raw callbacks stay opaque.
5type Command<W:Type> is Type:
6  Raw{apply:W -> W}
7  Observed{apply:Facts.State -> W -> W & Facts.State}
8def run(~W:Type,command:Command<W>,world:W,trace:Facts.State) -> W & Facts.State:
9  match command:
10    case Raw{apply}:(apply(world),trace)
11    case Observed{apply}:apply(trace,world)
12def world_only(~W:Type,result:W & Facts.State) -> W:
13  match result:
14    case (world,_):world
15def run_disabled(~W:Type,command:Command<W>,world:W) -> W:
16  world_only(~W,run(~W,command,world,Facts.Off{}))