Method parse_let_expr

leanr-syntax/src/parser.rs:431–461

Parse let expression

(&mut self)

    /// Parse let expression
    fn parse_let_expr(&mut self) -> crate::Result<Expr> {
        if self.check(&TokenKind::Let) {
            let start = self.advance().span;
            let name = self.parse_ident()?;

            let type_ = if self.check(&TokenKind::Colon) {
                self.advance();
                Some(Box::new(self.parse_expr()?))
            } else {
                None
            };

            self.expect(TokenKind::ColonEq)?;
            let value = Box::new(self.parse_expr()?);

            self.expect(TokenKind::In)?;
            let body = Box::new(self.parse_expr()?);

            let span = start.to(body.span());

            Ok(Expr::Let {
                span,
                name,
                type_,
                value,
                body,
            })
        } else {
            self.parse_match_expr()
        }
    }

    /// Parse match expression
    fn parse_match_expr(&mut self) -> crate::Result<Expr> {