Enum Trigger 

pub enum Trigger<'a> {
    PageLoads,
    Appears,
    Disappears,
    RouteChanges,
    Online,
    Offline,
    Selector {
        selector: &'a Expr<'a>,
        event: Symbol,
        key: Option<Symbol>,
    },
    Key {
        key: Symbol,
    },
    FieldChanges {
        store: Option<Symbol>,
        field: Symbol,
    },
    Every {
        seconds: &'a Expr<'a>,
        name: Option<Symbol>,
    },
    After {
        seconds: &'a Expr<'a>,
        name: Option<Symbol>,
    },
    Message {
        topic: &'a Expr<'a>,
        param: (Symbol, &'a TypeExpr<'a>),
    },
    ActionFails {
        param: Symbol,
    },
    FetchFails {
        url: Symbol,
        error: Symbol,
    },
    WindowResizes,
    ScrollsToBottom {
        selector: Option<&'a Expr<'a>>,
    },
    FileDropped {
        selector: &'a Expr<'a>,
        param: (Symbol, &'a TypeExpr<'a>),
    },
}

What an English When …: sentence in Actions: waits for.

Variants

PageLoads

When the page loads:

Appears

When this component appears:

Disappears

When this component disappears:

RouteChanges

When the route changes:

Online

When the app comes back online:

Offline

When the app goes offline:

Selector

When "#add" is submitted: / When "#draft" changes: / When the user types in "#q": / When the user presses Escape in "#draft": (key set) / When "#x" is focused: …

Fields

selector: &'a Expr<'a>

event: Symbol

key: Option<Symbol>

Key

When the user presses Escape: — a key anywhere on the page.

Fields

key: Symbol

FieldChanges

When todos change: / When Session's name changes:

Fields

store: Option<Symbol>

field: Symbol

Every

Every 60 seconds: — repeating. Every 60 seconds as refresh: names it, and a named timer is the only kind Stop the timer … can reach.

Fields

seconds: &'a Expr<'a>

name: Option<Symbol>

After

After 5 seconds: — one-shot, optionally named so it can be cancelled before it fires.

Fields

seconds: &'a Expr<'a>

name: Option<Symbol>

Message

When a message arrives on "topic" (m: T):

Fields

topic: &'a Expr<'a>

param: (Symbol, &'a TypeExpr<'a>)

ActionFails

When an action fails (error: Text):

Fields

param: Symbol

FetchFails

When a fetch fails (url: Text) and (error: Text):

Fields

url: Symbol

error: Symbol

WindowResizes

When the window resizes:

ScrollsToBottom

When the user scrolls to the bottom [of "#list"]:

Fields

selector: Option<&'a Expr<'a>>

FileDropped

When a file is dropped on "#zone" (file: File): or (name: Text) — the declared type decides what binds: File the whole record, Text just the name, same as [Trigger:: Message]’s own (Symbol, &TypeExpr) shape keeps its payload’s declared type.

Fields

selector: &'a Expr<'a>

param: (Symbol, &'a TypeExpr<'a>)

Implementations

impl<'a> Trigger<'a>

pub fn undeliverable(&self) -> Option<(&'static str, &'static str)>

★ THE TRIGGERS NO TIER DELIVERS — one table, read by every tier that has to say so.

Some((sentence, needs)) when nothing anywhere can fire this trigger yet; None when some tier delivers it.

The distinction is not pedantic, and getting it wrong produced a false statement in a compiler message: the browser-tier mount refusal ended “The tree-walker renders it; the bytecode tier cannot yet”, which is true of Every … seconds: and false of When the window resizes: — nothing renders that one. An author would have been told their page works on the tree-walker and sent looking for a tier to run it on.

It lives here because every tier has to agree about which sentences exist at all, and a second copy of a list is how they stop agreeing.

impl<'a> Trigger<'a>

pub fn form(&self) -> &'static str

The English FORM this trigger is written in — the words an author would search their own file for.

★ DELIBERATELY WITHOUT THE VALUES, and that is the difference from Self::shape. shape is a stable debug rendering for snapshot tests, and it prints what the AST holds: a duration comes out as every 60000000000ms, which is true and is not what anybody typed. A refusal is read by the person who wrote the sentence, so it names the FORM (Every … seconds:) and lets them find the line. Two renderings because there are two audiences; kept adjacent so neither can be changed without seeing the other.

pub fn shape(&self, interner: &Interner) -> String

A compact rendering for locks and tooling.

Trait Implementations

impl<'a> Clone for Trigger<'a>

fn clone(&self) -> Trigger<'a>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Debug for Trigger<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.