Method parse_params

leanr-syntax/src/parser.rs:275–314

Parse function parameters

(&mut self)

    /// Parse function parameters
    fn parse_params(&mut self) -> crate::Result<Vec<Param>> {
        let mut params = Vec::new();

        while self.check(&TokenKind::LParen) || self.check(&TokenKind::LBrace) {
            let implicit = self.check(&TokenKind::LBrace);
            let start = self.current().span;
            self.advance();

            let mut names = vec![self.parse_ident()?];

            // Multiple names: (x y z : T)
            while !self.check(&TokenKind::Colon) && !self.is_eof() {
                names.push(self.parse_ident()?);
            }

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

            let end_token = if implicit {
                TokenKind::RBrace
            } else {
                TokenKind::RParen
            };

            let end = self.expect(end_token)?.span;

            params.push(Param {
                span: start.to(end),
                names,
                type_,
                implicit,
            });
        }

        Ok(params)
    }

    /// Parse an expression
    pub fn parse_expr(&mut self) -> crate::Result<Expr> {