Struct Envelope 

pub struct Envelope<'a> {
    pub count: usize,
    pub exhausted: bool,
    pub solutions: &'a [RenderedSolution],
    pub program_output: Option<&'a str>,
    pub atoms: Option<&'a [String]>,
}

The fixed engine-output shape — the contract, made a type. Every encoding reads the same fields; only their byte encoding varies.

Fields

count: usize

exhausted: bool

solutions: &'a [RenderedSolution]

program_output: Option<&'a str>

Captured write/1 bytes, when the sink is in capture mode. None when output streamed to stdout (the CLI text path). Encodings that can’t stream require the caller to have run in capture mode so this is Some.

atoms: Option<&'a [String]>

The atom map (id → name, id = array index), when the bson output is self-describing (--atoms). Lets a host decode bson term values (atom- id-keyed TermBuf) from the single document — no external atom source. Emitted post-query, so it covers query-introduced atoms too.

Implementations

impl<'a> Envelope<'a>

pub fn from_machine(m: &'a Machine, exhausted: bool) -> Self

Build from the machine’s solved state. program_output follows the machine’s output sink: None when streaming to stdout, Some(..) when capturing — so one constructor serves both the CLI and the reactor.