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Diffstat (limited to 'doc/context/sources/general/manuals/luatex/luatex-modifications.tex')
| -rw-r--r-- | doc/context/sources/general/manuals/luatex/luatex-modifications.tex | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/doc/context/sources/general/manuals/luatex/luatex-modifications.tex b/doc/context/sources/general/manuals/luatex/luatex-modifications.tex index 10b4fd7a4..af2c69363 100644 --- a/doc/context/sources/general/manuals/luatex/luatex-modifications.tex +++ b/doc/context/sources/general/manuals/luatex/luatex-modifications.tex @@ -1255,6 +1255,28 @@ previous code (that mostly used \type {getc} calls), it can be quite a bit faste \stopsubsection +\startsubsection[title=Tabs and spaces] + +We conform to the way other \TEX\ engines handle trailing tabs and spaces. For +decades trailing tabs and spaces (before a newline) were removed from the input +but this behaviour was changed in September 2017 to only handle spaces. We are +aware that this can introduce compatibility issues in existing workflows but +because we don't want too many differences with upstream \TEXLIVE\ we just follow +up on that patch (which is a functional one and not really a fix). It is up to +macro packages maintainers to deal with possible compatibility issues and in +\LUATEX\ they can do so via the callbacks that deal with reading from files. + +The previous behaviour was a known side effect and (as that kind of input +normally comes from generated sources) it was normally dealt with by adding a +comment token to the line in case the spaces and|/|or tabs were intentional and +to be kept. We are aware of the fact that this contradicts some of our other +choices but consistency with other engines and the fact that in \KPSE\ mode a +common file \IO\ layer is used can have a side effect of breaking compatibility. +We still stick to our view that at the log level we can (and might be) more +incompatible. + +\stopsubsection + \stopsection \stopchapter |