Method push_alternate

regex/regex-syntax/src/ast/parse.rs:656–665

Parse and push a single alternation on to the parser's internal stack. If the top of the stack already has an alternation, then add to that instead of pushing a new one. The concatenation given corresponds to a single alternation branch. The concatenation returned starts the next branch and is empty. This assumes the parser is currently positioned at `|` and will advance the parser to the charac

(&self, mut concat: ast::Concat)

    /// This assumes the parser is currently positioned at `|` and will advance
    /// the parser to the character following `|`.
    fn push_alternate(&self, mut concat: ast::Concat) -> Result<ast::Concat> {
        assert_eq!(self.char(), '|');
        concat.span.end = self.pos();
        self.push_or_add_alternation(concat);
        self.bump();
        Ok(ast::Concat {
            span: self.span(),
            asts: vec![],
        })
    }

    /// Pushes or adds the given branch of an alternation to the parser's
    /// internal stack of state.