Function _group

sqlparse/engine/grouping.py:478–525

Groups together tokens that are joined by a middle token. i.e. x < y

(tlist, cls, match,
           valid_prev=lambda t: True,
           valid_next=lambda t: True,
           post=None,
           extend=True,
           recurse=True,
           depth=0
           )

def _group(tlist, cls, match,
           valid_prev=lambda t: True,
           valid_next=lambda t: True,
           post=None,
           extend=True,
           recurse=True,
           depth=0
           ):
    """Groups together tokens that are joined by a middle token. i.e. x < y"""
    if MAX_GROUPING_DEPTH is not None and depth > MAX_GROUPING_DEPTH:
        raise SQLParseError(
            f"Maximum grouping depth exceeded ({MAX_GROUPING_DEPTH})."
        )

    # Limit the number of tokens to prevent DoS attacks
    if MAX_GROUPING_TOKENS is not None \
       and len(tlist.tokens) > MAX_GROUPING_TOKENS:
        raise SQLParseError(
            f"Maximum number of tokens exceeded ({MAX_GROUPING_TOKENS})."
        )

    tidx_offset = 0
    pidx, prev_ = None, None
    token_list = list(tlist)

    for idx, token in enumerate(token_list):
        tidx = idx - tidx_offset
        if tidx < 0:  # tidx shouldn't get negative
            continue

        if token.is_whitespace:
            continue

        if recurse and token.is_group and not isinstance(token, cls):
            _group(token, cls, match, valid_prev, valid_next,
                   post, extend, True, depth + 1)

        if match(token):
            nidx, next_ = tlist.token_next(tidx)
            if prev_ and valid_prev(prev_) and valid_next(next_):
                from_idx, to_idx = post(tlist, pidx, tidx, nidx)
                grp = tlist.group_tokens(cls, from_idx, to_idx, extend=extend)

                tidx_offset += to_idx - from_idx
                pidx, prev_ = from_idx, grp
                continue

        pidx, prev_ = tidx, token