Enum Control 

pub enum Control {
    If {
        arms: Vec<Branch>,
        otherwise: Option<Vec<Expr>>,
    },
    While {
        test: Vec<Expr>,
        body: Vec<Expr>,
        body_first: bool,
        until: bool,
    },
    For {
        name: Option<String>,
        source: Box<Expr>,
        body: Vec<Expr>,
    },
    Select {
        subject: Box<Expr>,
        cases: Vec<Branch>,
    },
    Try {
        body: Vec<Expr>,
        catch: Vec<Expr>,
    },
    Return,
    Break,
    Branch(Box<Expr>),
    Continue,
}

A control-flow sentence. Every body is a block: a list of sentences whose value is the last one’s.

Variants

If

if. T do. B elseif. T do. B else. B end., and APL’s :If family. The arms are tested in order; otherwise is the else. body.

Fields

arms: Vec<Branch>

otherwise: Option<Vec<Expr>>

While

while. and whilst., APL’s :While and :Repeat. body_first runs the body once before the first test; until inverts the test.

Fields

test: Vec<Expr>

body: Vec<Expr>

body_first: bool

until: bool

For

for. y do. B end. / for_i. / :For i :In y. name binds each item and <name>_index its position.

Fields

name: Option<String>

source: Box<Expr>

body: Vec<Expr>

Select

select. T case. S do. B end. and :Select. A case with no test is the default (case. do., :Else); fall_through is fcase..

Fields

subject: Box<Expr>

cases: Vec<Branch>

Try

try. B catch. B end.. The catch block runs on a language error; a gap in libjay itself is never caught.

Fields

body: Vec<Expr>

catch: Vec<Expr>

Return

return. / :Return: leave the definition with the value in hand.

Break

break. / :Leave: leave the innermost loop.

Branch(Box<Expr>)

APL → e: continue at the line e names. An empty value falls through to the next line; anything that is not a line of this definition — →0 above all — leaves it.

Continue

continue. / :Continue: start the innermost loop’s next iteration.

Trait Implementations

impl Clone for Control

fn clone(&self) -> Control

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Control

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

Formats the value using the given formatter.