Struct Variable 

pub struct Variable {
    pub id: VarId,
    pub subject: String,
    pub key: String,
    pub kind: VarKind,
    pub verb: String,
    pub span: Span,
    pub set: Option<String>,
    pub shows: Vec<(Option<String>, String)>,
}

A state of the system: “the kettle is off | heating | dry”.

Fields

id: VarId

subject: String

As declared, e.g. “the kettle”.

key: String

Normalised for matching, e.g. “kettle”.

kind: VarKind

verb: String

The verb it was declared with, which steps about it read with: “is”, “are”, “has” (“the drawing has 0..100 shapes”) or “have”.

span: Span

set: Option<String>

How docs tell the reader to change it, with {value} for the value (“open the dial to {value}”). Without it: “set the dial to 80 %”.

shows: Vec<(Option<String>, String)>

What the reader sees, from Shows: lines: for one value (“dry”, “the display says DRY”, or “at least 99 %” for a number), or for any value with {value} in it (None, “the button reads UPLOAD {value}”).

Implementations

impl Variable

pub fn shown_shift(&self, shift: Shift) -> Option<String>

What the reader sees when it’s exactly one value, if a Shows: line says. What the reader sees when it changes by shift, if a Shows: line says: one keyed “goes up by 1”, “goes down by 10 m” or “stays the same”, as relative Thens write them.

pub fn shown(&self, c: &Constraint) -> Option<String>

pub fn full(&self) -> Constraint

The constraint that allows every value.

pub fn value_index(&self, name: &str) -> Option<usize>

pub fn witness(&self, c: &Constraint) -> Option<Value>

A concrete value inside c to drive the system with: the first allowed name, or the middle of a numeric range.

pub fn admits(&self, c: &Constraint, v: &Value) -> bool

Does the observed value satisfy c? Numbers get a tolerance of a millionth of the state’s range, so a value that went through an f32 still reads as what it was set to.

pub fn describe(&self, c: &Constraint) -> String

“the kettle is heating”, “the dial is above 55 %”.

pub fn predicate(&self, c: &Constraint) -> String

“is heating”, “is not dry”, “is between 20 and 40 %” (“are …” for a plural subject).

Trait Implementations

impl Clone for Variable

fn clone(&self) -> Variable

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Variable

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

Formats the value using the given formatter.