On Tue, Sep 29, 2026 at 08:28:54AM +0300, Eli Zaretskii wrote:
> Btw, where in the Texinfo sources and/or documentation can one find a
> comprehensive information about this quoting, which could then be used
> to implement its support in Emacs? I found only two places in the
> Texinfo manual that talk about this:
>
> • Unfortunately, you cannot reliably use periods, commas, or colons
> within a node name; these can confuse some Info readers.
> ‘texi2any’ quotes problematic node names and labels by default, but
> some Info readers do not recognize this syntax. Node name and
> label quoting causes ‘DEL’ characters (‘CTRL-?’, character number
> 127, often rendered as ‘^?’) to appear around the name. To remove
> node names and labels quoting, you can set the customization
> variable ‘INFO_SPECIAL_CHARS_QUOTE’ to ‘0’ (*note Info and
> Plaintext Customization Variables::).
>
> ‘texi2any’ warns about such problematic usage in node names, menu
> items, and cross-references. If you don't want to see the
> warnings, you can set the customization variable
> ‘INFO_SPECIAL_CHARS_WARNING’ to ‘0’ (*note Info and Plaintext
> Customization Variables::).
> [...]
> If <label> contains a colon character (:), it should be surrounded
> with a pair of <del> characters. Likewise, quoting characters may be
> used for the node name if it contains problematic characters; then a
> terminating comma or period is not needed. As stated earlier, this
> quoting mechanism is not supported in all Info-reading programs.
>
> Is this all that there is to know, or are there other aspects of this?
It is used in the node information line if the node name contains a
comma (possibly for other problematic characters also), and is also used
for pointers to nodes in the node information line if the name of the
referenced node contains a comma.
It's in this text in the manual:
Regular nodes look like this:
<node> =
<separator>
File: <fn>, Node: <id1>, (Next: <id2>, )? (Prev: <id3>, )? Up: <id4>
<general text, until the next ^_ or end-of-file>
At least one space or tab must be present after each colon and comma,
but any number of spaces are ignored. The <id> node identifiers have
following format:
<id> = (<lparen><infofile><rparen>)?<node-spec>?
<node-spec> = <nodename> | <del><nodename><del>
<del> = ^?
...
Node names containing periods, commas, colons or parentheses can
confuse Info readers. If it is necessary to refer to a node whose name
contains any of these, the <nodename> should be surrounded by a pair of
‘DEL’ characters (‘CTRL-?’, character number 127). ‘makeinfo’ adds
these characters when needed in the default case. Note that not all
Info readers recognize this syntax. *Note Info Node Names
Constraints::.
Info node "(texinfo)Info Format Regular Nodes".
Note also that the DEL-quoting mechanism is not used in the Tag Table
section of the Info file.
> Also, where in the stand-alone Info reader is this quoting handled?
> Is read_quoted_string the only place?
It's anywhere that INFO_QUOTE or INFO_QUOTE_STR (defined in scan.h) is
used. It is nearly all in scan.c in the functions read_quoted_string,
scan_reference_label, scan_reference_target and scan_node_contents. It
is also used in one place in indices.c (in format_reference) when
generating a node.
>
> Thanks.
>
