Struct OpDef 

pub struct OpDef {
    pub readings: [Result<Verb, String>; 4],
}

An operator dfn’s body, parsed once for each reading of its operands.

Whether ⍺⍺ names a function or an array decides how the body PARSES, not merely what it computes: ⍺⍺+⍵ is a train under the first reading and a sum under the second. The body is therefore parsed both ways — four ways when it takes a right operand as well — when the dfn is defined, and the operands choose the reading when they arrive.

Fields

readings: [Result<Verb, String>; 4]

Indexed by (⍺⍺ is an array) + 2 × (⍵⍵ is an array). Err holds what the body said when it would not parse that way, so choosing that reading reports the body’s own complaint.

Implementations

impl OpDef

pub fn uniform(v: Verb) -> OpDef

The one reading with a body under every combination of operands: what a dfn that mentions neither ⍺⍺ nor ⍵⍵ would need, and the shape a frontend uses before it has parsed the alternatives.

pub fn pick(&self, alpha: &Operand, omega: Option<&Operand>) -> Result<&Verb>

The body as it parses for these operands.

Trait Implementations

impl Debug for OpDef

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

Formats the value using the given formatter.