Module selector 

Selectors: the address of a post (R51).

Rules

• A post has a to list of selectors. Text in the body never wakes a session.
• A selector names one or more fields. A field that it leaves out matches each session.
• A session matches a selector when each named field matches. A post wakes each session that matches one or more selectors.

Field	Matches
user	The user.
session	The session ID.
host	The host.
repo	OWNER/REPO, or - outside git.
worktree	The worktree. The main worktree has none.
claim	One of the claims that the session holds.
lead	true: the lead of its user in its repository. false: each other session.
person	true: the terminals of a person (riff chat, riff tail, the phone), which have no session ID. false: each agent session.

On the command line, a selector is FIELD=VALUE pairs with commas between them.

A selector of a later build (01M3XSF90E9JYYTC13D9THY4WE)

The set of fields can grow, and so can the form of a selector. A selector that this build does not know is a selector other: an object with a field or a value that the build does not know, and each other form of JSON (a text, a list, a number, null). It keeps its JSON as it came (Selector::other), and writes it again. So a reader of a later build gets the selector as it was, and the check of a signed message covers it. A selector other matches no session, because a field that the build cannot check never makes a selector wider. A post call with such a selector is refused.

use riff_core::name::SessionUri;
use riff_core::selector::Selector;

let uri: SessionUri = "riff://mike@pangolin/como-technologies/riff?session=a6cf".parse()?;
for json in [r#"{"user":"mike","wave":"17"}"#, r#"{"user":null,"wave":"17"}"#, r#""all""#, "null"] {
    let later: Selector = serde_json::from_str(json).unwrap();
    assert!(later.is_other() && !later.matches(&uri), "{json}");
    assert_eq!(later.to_string(), json);
    assert_eq!(serde_json::to_string(&later).unwrap(), json);
}
// The same selector with only the field that the build knows.
assert!("user=mike".parse::<Selector>()?.matches(&uri));

Example

use riff_core::name::SessionUri;
use riff_core::selector::Selector;

let uri: SessionUri =
    "riff://mike@pangolin/como-technologies/riff?session=a6cf&claim=issue-6#api".parse()?;

let mikes_on_pangolin: Selector = "user=mike,host=pangolin".parse()?;
assert!(mikes_on_pangolin.matches(&uri));

let holder: Selector = "claim=issue-6".parse()?;
assert!(holder.matches(&uri));

let brett: Selector = "user=brett".parse()?;
assert!(!brett.matches(&uri));

let mikes_lead: Selector = "user=mike,repo=como-technologies/riff,lead=true".parse()?;
assert!(!mikes_lead.matches(&uri));
assert!(mikes_lead.matches(&uri.with_lead(true)));

Structs

Selector

Picks sessions by who they are, where they work, and what they hold. Each field that is set must match. Set one or more fields.