Halting

How an execution frame ends (Yellow Paper §9.4.2). A frame either halts normally — one of HaltKind: STOP, RETURN, REVERT, or SELFDESTRUCT — or enters the exceptional halting state, one of ExceptionKind. An exceptional halt consumes all remaining gas and reverts the frame's state changes. REVERT (EIP-140) is the sole failure mode that instead refunds the remaining gas while still rolling state back.

FrameStatus is the running/halted/exceptional tag. RETURN and REVERT carry the frame output directly; interpret returns that value.

type HaltKind

Ordinary frame stops. Only RETURN and REVERT produce output bytes.

union HaltKind = {
  /* STOP: success, empty return data */
  HaltStop : unit,
  /* RETURN: success with output data */
  HaltReturn : OutputSlice,
  /* REVERT: state unwound, output kept (EIP-140) */
  HaltRevert : OutputSlice,
  /* SELFDESTRUCT: success, empty return data */
  HaltSelfDestruct : unit
}

type FrameStatus

Per-frame execution status: running, halted normally, or exceptionally halted.

union FrameStatus = {
  /* mid-execution */
  Running : unit,
  /* halted normally (YP §9.4.4) */
  Halted : HaltKind,
  /* halted exceptionally: all frame gas consumed, effects void */
  Exceptional : ExceptionKind
}