Struct egg::RecExpr

pub struct RecExpr<L> { /* fields omitted */ }

A recursive expression from a user-defined Language.

This is type is essentially an ENode whose children are RecExprs. This is resource counted with Rc, so it's cheap to clone.

If the serde-1 feature is enabled, this implements serde::Serialize by pretty-printing with self.pretty(80).

Methods

impl<L: Language + Display> RecExpr<L>

pub fn pretty(&self, width: usize) -> String

Pretty print with a maximum line length.

This gives you a nice, indented, pretty-printed s-expression.

Example

define_language! {
    enum FooLanguage {
        Num(i32),
        Add = "+",
        Mul = "*",
        Symbol(String),
    }
}

let e: RecExpr<FooLanguage> = "(* (+ 2 2) (+ x y))".parse().unwrap();
assert_eq!(e.pretty(10), "
(*
  (+ 2 2)
  (+ x y))
".trim());

Trait Implementations

impl<L> AsRef<ENode<L, RecExpr<L>>> for RecExpr<L>

fn as_ref(&self) -> &ENode<L, RecExpr<L>>

Performs the conversion.

impl<L> Borrow<ENode<L, RecExpr<L>>> for RecExpr<L>

fn borrow(&self) -> &ENode<L, RecExpr<L>>

Immutably borrows from an owned value.

impl<L: Clone> Clone for RecExpr<L>

fn clone(&self) -> RecExpr<L>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<L: Debug> Debug for RecExpr<L>

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

Formats the value using the given formatter.

impl<L: Eq> Eq for RecExpr<L>

impl<L> From<ENode<L, RecExpr<L>>> for RecExpr<L>

fn from(inner: ENode<L, RecExpr<L>>) -> Self

Performs the conversion.

impl<L: Language> From<RecExpr<L>> for Pattern<L>

fn from(e: RecExpr<L>) -> Self

Performs the conversion.

impl<L: Language + FromStr> FromStr for RecExpr<L>

type Err = ParseError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, ParseError>

Parses a string s to return a value of this type.

impl<L: Hash> Hash for RecExpr<L>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl<L: PartialEq> PartialEq<RecExpr<L>> for RecExpr<L>

fn eq(&self, other: &RecExpr<L>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &RecExpr<L>) -> bool

This method tests for !=.

impl<L> StructuralEq for RecExpr<L>

impl<L> StructuralPartialEq for RecExpr<L>

impl<L: Language> TryFrom<Pattern<L>> for RecExpr<L>

type Error = String

The type returned in the event of a conversion error.

fn try_from(pat: Pattern<L>) -> Result<RecExpr<L>, String>

Performs the conversion.