[tex-live] Format file in quotes not parsed by pdflatex

Zdenek Wagner zdenek.wagner at gmail.com
Sun May 19 00:02:17 CEST 2013

2013/5/18 Philip Taylor <P.Taylor at rhul.ac.uk>:
> Zdenek Wagner wrote:
>> In other words, in Knuth's TeX it is impossible to use a space in the
>> file name.
> Yes, I understand that Zdeněk :  I was thinking specifically of
> "extended" TeX's
> (e-TeX, PdfTeX, XeTeX, LuaTeX, etc.), where a greater degree of
> flexibility is
> permissble.  Presumably these engines (XeTeX, at least) can handle filenames
> with arbitrary Unicode characters, so also permitting a space would be of
> great benefit to those using an operating system that encourages the use
> of spaces in filenames and paths.
Yes, but care is needed. Suppose you write

\input some-file

Unless you change catcodes, \endlinechar etc, TeX mouth will create
control sequence "input" followed by some (with catcode 11), hyphen
(catcode 12), file (catcode 11), and a space token because this is how
the end of line is handled. TeX stomach will see the control sequence
followed by the above mentioned material. It now cannot distinguish
the space token emerging from the end of line from the space token
entered directly from the keyboard or as ^^20. Imagine that you do not
leave a blank line after \input, eg you wite something as:

\input macros
This is the beginning of my document...

If spaces in the file names were allowed without explicite escaping,
the whole paragraph would turn into a file name and the backward
compatibility would be lost. Quotes provide good solution because old
filesystems did not allow quotes in the file names. Thus an old
document using quotes inside the file name cannot exist.

> ** Phil.

Zdeněk Wagner

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