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use crate::ast;
use crate::{
Parse, ParseError, Parser, Peek, Peeker, Resolve, ResolveError, ResolveOwned, Spanned, Storage,
ToTokens,
};
use runestick::Source;
use std::borrow::Cow;
/// Parse an object expression.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ExprObject>("Foo {\"foo\": 42}");
/// testing::roundtrip::<ast::ExprObject>("#{\"foo\": 42}");
/// testing::roundtrip::<ast::ExprObject>("#{\"foo\": 42,}");
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Parse, ToTokens, Spanned)]
pub struct ExprObject {
/// Attributes associated with object.
#[rune(iter, meta)]
pub attributes: Vec<ast::Attribute>,
/// An object identifier.
#[rune(meta)]
pub ident: ObjectIdent,
/// Assignments in the object.
pub assignments: ast::Braced<FieldAssign, T![,]>,
}
impl Peek for ExprObject {
fn peek(p: &mut Peeker<'_>) -> bool {
match (p.nth(0), p.nth(1)) {
(K![ident], K!['{']) => true,
(K![#], K!['{']) => true,
_ => false,
}
}
}
/// A literal object identifier.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Spanned)]
pub enum ObjectIdent {
/// An anonymous object.
Anonymous(T![#]),
/// A named object.
Named(ast::Path),
}
impl Parse for ObjectIdent {
fn parse(p: &mut Parser) -> Result<Self, ParseError> {
Ok(match p.nth(0)? {
K![#] => Self::Anonymous(p.parse()?),
_ => Self::Named(p.parse()?),
})
}
}
/// A literal object field.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Spanned)]
pub struct FieldAssign {
/// The key of the field.
pub key: ObjectKey,
/// The assigned expression of the field.
#[rune(iter)]
pub assign: Option<(T![:], ast::Expr)>,
}
/// Parse an object literal.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::FieldAssign>("\"foo\": 42");
/// testing::roundtrip::<ast::FieldAssign>("\"foo\": 42");
/// testing::roundtrip::<ast::FieldAssign>("\"foo\": 42");
/// ```
impl Parse for FieldAssign {
fn parse(p: &mut Parser) -> Result<Self, ParseError> {
let key = p.parse()?;
let assign = if p.peek::<T![:]>()? {
let colon = p.parse()?;
let expr = p.parse::<ast::Expr>()?;
Some((colon, expr))
} else {
None
};
Ok(Self { key, assign })
}
}
/// Possible literal object keys.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Spanned)]
pub enum ObjectKey {
/// A literal string (with escapes).
LitStr(ast::LitStr),
/// A path, usually an identifier.
Path(ast::Path),
}
/// Parse an object literal.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ObjectKey>("foo");
/// testing::roundtrip::<ast::ObjectKey>("\"foo \\n bar\"");
/// ```
impl Parse for ObjectKey {
fn parse(p: &mut Parser) -> Result<Self, ParseError> {
Ok(match p.nth(0)? {
K![str] => Self::LitStr(p.parse()?),
K![ident] => Self::Path(p.parse()?),
_ => {
return Err(ParseError::expected(&p.tok_at(0)?, "literal object key"));
}
})
}
}
/// A tag object to help peeking for anonymous object case to help
/// differentiate anonymous objects and attributes when parsing block
/// expressions.
pub struct AnonExprObject;
impl Peek for AnonExprObject {
fn peek(p: &mut Peeker<'_>) -> bool {
matches!((p.nth(0), p.nth(1)), (K![#], K!['{']))
}
}
impl<'a> Resolve<'a> for ObjectKey {
type Output = Cow<'a, str>;
fn resolve(&self, storage: &Storage, source: &'a Source) -> Result<Self::Output, ResolveError> {
Ok(match self {
Self::LitStr(lit_str) => lit_str.resolve(storage, source)?,
Self::Path(path) => {
let ident = match path.try_as_ident() {
Some(ident) => ident,
None => {
return Err(ResolveError::expected(path, "object key"));
}
};
ident.resolve(storage, source)?
}
})
}
}
impl ResolveOwned for ObjectKey {
type Owned = String;
fn resolve_owned(
&self,
storage: &Storage,
source: &Source,
) -> Result<Self::Owned, ResolveError> {
Ok(self.resolve(storage, source)?.into_owned())
}
}