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use crate::ast;
use crate::{Parse, Peek, Peeker, Spanned, ToTokens};
/// An if statement: `if cond { true } else { false }`
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ExprIf>("if 0 { }");
/// testing::roundtrip::<ast::ExprIf>("if 0 { } else { }");
/// testing::roundtrip::<ast::ExprIf>("if 0 { } else if 0 { } else { }");
/// testing::roundtrip::<ast::ExprIf>("if let v = v { }");
/// testing::roundtrip::<ast::ExprIf>("#[attr] if 1 {} else {}");
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Parse, ToTokens, Spanned)]
#[rune(parse = "meta_only")]
pub struct ExprIf {
/// The `attributes` of the if statement
#[rune(iter, meta)]
pub attributes: Vec<ast::Attribute>,
/// The `if` token.
pub if_: T![if],
/// The condition to the if statement.
pub condition: ast::Condition,
/// The body of the if statement.
pub block: Box<ast::Block>,
/// Else if branches.
#[rune(iter)]
pub expr_else_ifs: Vec<ExprElseIf>,
/// The else part of the if expression.
#[rune(iter)]
pub expr_else: Option<ExprElse>,
}
expr_parse!(If, ExprIf, "if expression");
/// An else branch of an if expression.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Parse, Spanned)]
pub struct ExprElseIf {
/// The `else` token.
pub else_: T![else],
/// The `if` token.
pub if_: T![if],
/// The condition for the branch.
pub condition: ast::Condition,
/// The body of the else statement.
pub block: Box<ast::Block>,
}
impl Peek for ExprElseIf {
fn peek(p: &mut Peeker<'_>) -> bool {
matches!((p.nth(0), p.nth(1)), (K![else], K![if]))
}
}
/// An else branch of an if expression.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Parse, Spanned)]
pub struct ExprElse {
/// The `else` token.
pub else_: T![else],
/// The body of the else statement.
pub block: Box<ast::Block>,
}
impl Peek for ExprElse {
fn peek(p: &mut Peeker<'_>) -> bool {
matches!(p.nth(0), K![else])
}
}