Enum Expr 

pub enum Expr {
    Const(Array, Span),
    Param(usize, Span),
    Name(String, Span),
    Assign {
        name: String,
        value: Box<Expr>,
        scope: Scope,
        span: Span,
    },
    AmendIndex {
        name: String,
        slots: Vec<Option<Expr>>,
        value: Box<Expr>,
        origin: i64,
        scope: Scope,
        span: Span,
    },
    Control(Box<Control>, Span),
    Monad {
        verb: Verb,
        y: Box<Expr>,
        span: Span,
    },
    Dyad {
        verb: Verb,
        x: Box<Expr>,
        y: Box<Expr>,
        span: Span,
    },
    PrintPass {
        value: Box<Expr>,
        span: Span,
    },
    Fused {
        kernel: FusedKernel,
        inputs: Vec<Expr>,
        orig: Box<Expr>,
        span: Span,
    },
    Elided {
        orig: Vec<Expr>,
        span: Span,
    },
    VerbDef {
        name: String,
        verb: Verb,
        span: Span,
    },
}

Variants

Const(Array, Span)

Param(usize, Span)

A bound parameter, by position in Program::params.

Name(String, Span)

A name assigned earlier in the same program.

Assign

Yields the assigned value in expression position; a whole sentence that is an assignment displays nothing at the top level.

Fields

name: String

value: Box<Expr>

scope: Scope

span: Span

AmendIndex

APL A[i;j]←v: the named value with the part the brackets select replaced. The name is read, a copy is written, and the copy takes the name’s place. An elided slot selects its whole axis.

Fields

name: String

slots: Vec<Option<Expr>>

value: Box<Expr>

origin: i64

scope: Scope

span: Span

Control(Box<Control>, Span)

A control-flow sentence (J’s control words, APL’s :If family). Its value is the value of the last sentence the branch it chose executed. Only an explicit definition’s body holds one: neither language allows a control word outside a definition.

Monad

Fields

verb: Verb

y: Box<Expr>

span: Span

Dyad

Fields

verb: Verb

x: Box<Expr>

y: Box<Expr>

span: Span

PrintPass

APL ⎕← expr: print, pass the value through.

Fields

value: Box<Expr>

span: Span

Fused

A chain of elementwise verbs evaluated in one blockwise pass (see crate::fuse). inputs are the subtrees the chain reads; orig is the chain itself, which runs whenever the kernel declines.

Fields

kernel: FusedKernel

inputs: Vec<Expr>

orig: Box<Expr>

span: Span

Elided

A marker the fusion pass leaves when it has rewritten the program across sentence boundaries: it does nothing and yields nothing, and carries the sentences the program was compiled from so that crate::fuse::unfused can rebuild them.

Fields

orig: Vec<Expr>

span: Span

VerbDef

A sentence that named a verb (J mean =. +/ % #). The frontend has already substituted the verb into the later sentences that use the name, so nothing runs here; the node is kept so that the sentence still yields no value, and so that Program::explain can show it.

Fields

name: String

verb: Verb

span: Span

Implementations

impl Expr

pub fn span(&self) -> Span

pub fn set_span(&mut self, to: Span)

Widen (or move) the source this node points at. A parenthesised expression uses it to take in its own brackets, so that a caret under it underlines something balanced.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.