One compiled <invoke> element (spec 6.4) - the interned counterpart to Statifier.Document.Invoke, reachable only through its owning state as elem(machine.states, i).invoke, in document order.

index is this invocation's position within its own state's invoke list - what {:invoke, state_index, invoke_index} and {:finalize, state_index, invoke_index} name, Statifier.Compiler.Expressions.owner_ref/0's and Statifier.Machine.Content.owner/0's own new arms.

type and src each fold their own static/expr attribute pair into a single Machine.expr() | nil, mirroring Statifier.Machine.Donedata.expr: {:static, v} from type/src, {:compiled, ...} from typeexpr/srcexpr, nil when neither was written (an already-validated document never writes both - 6.4.1's "Must not occur with" pair).

id is the author's literal id attribute, used verbatim (ADR-0008 as amended - "document-authored IDs are always respected"). idlocation stays a raw, uncompiled location path string, never a compiled expression - the same reason Statifier.Machine.Content.Assign's moduledoc gives for its own location field: a location path cannot be resolved any earlier than execute time, even in principle.

namelist and params are kept as two separate lists of Statifier.Machine.Param.t(), every namelist entry compiled with kind: :location, even though 6.4's data-sharing rule treats the two channels identically at the invoked service - they stay apart here only so the validator can enforce 6.4.1's "namelist Must not occur with the <param> element" and so a later empty-<finalize> auto-assign can find its write targets by name. A namelist entry that fails to compile as a location expression does not fail Statifier.Compiler.compile/1: it carries {:invalid, error} on the entry's expr (5.9.4 deferral, see Statifier.Machine.Param) and aborts the invocation at execute time - Interpreter.resolve_params/2 - rather than at load time.

content folds <content>'s markup into a single Machine.expr(), exactly as Machine.Donedata.expr does - nil when <invoke> has no <content> child.

finalize is nil when <invoke> has no <finalize> child at all, and a Statifier.Machine.Block.t() (possibly with an empty content list) when it does - the same absent-versus-empty distinction Statifier.Document.Invoke's moduledoc describes, carried through compilation structurally. Unlike every other field here, its c_indexes come from the same dense, whole-machine counter every <onentry>/<onexit> block uses - <finalize> is executable content, the other fields are not.

attribute_locations is Statifier.Document.Invoke's own map, carried through unchanged rather than distilled into individual *_location fields the way most other compiled nodes are: an <invoke> has eight source attributes and this struct has no per-field diagnostic use for most of them, so the one shared map stands in for all of them at once.