A Question About futurelet
Here is something I don't understand about futurelet, in this case, into macro xfl. I can successfully do the archetypal test of
ifxxfl x...
to test whether the next token is an x. When true, this would indicate that xfl replaces to an x. And yet, if I do a
detokenizeexpandafter{xfl}
I do not get an x as I would expect, but only an unexpandable xfl.
Why is that? Are there other tests I can perform than ifx on a futureletted token? Can't I truly capture (and save) that token?
documentclass{article}
usepackage[T1]{fontenc}
deffltest{futureletxflpdecide}
defpdecide{%
ifxxfl xrelax[Next character is x]else[Not x]fipar
(Can't detokenizedetokenizeexpandafter{xfl})par
}
begin{document}
fltest xyz
end{document}
tex-core
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
add a comment |
Here is something I don't understand about futurelet, in this case, into macro xfl. I can successfully do the archetypal test of
ifxxfl x...
to test whether the next token is an x. When true, this would indicate that xfl replaces to an x. And yet, if I do a
detokenizeexpandafter{xfl}
I do not get an x as I would expect, but only an unexpandable xfl.
Why is that? Are there other tests I can perform than ifx on a futureletted token? Can't I truly capture (and save) that token?
documentclass{article}
usepackage[T1]{fontenc}
deffltest{futureletxflpdecide}
defpdecide{%
ifxxfl xrelax[Next character is x]else[Not x]fipar
(Can't detokenizedetokenizeexpandafter{xfl})par
}
begin{document}
fltest xyz
end{document}
tex-core
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
add a comment |
Here is something I don't understand about futurelet, in this case, into macro xfl. I can successfully do the archetypal test of
ifxxfl x...
to test whether the next token is an x. When true, this would indicate that xfl replaces to an x. And yet, if I do a
detokenizeexpandafter{xfl}
I do not get an x as I would expect, but only an unexpandable xfl.
Why is that? Are there other tests I can perform than ifx on a futureletted token? Can't I truly capture (and save) that token?
documentclass{article}
usepackage[T1]{fontenc}
deffltest{futureletxflpdecide}
defpdecide{%
ifxxfl xrelax[Next character is x]else[Not x]fipar
(Can't detokenizedetokenizeexpandafter{xfl})par
}
begin{document}
fltest xyz
end{document}
tex-core
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
Here is something I don't understand about futurelet, in this case, into macro xfl. I can successfully do the archetypal test of
ifxxfl x...
to test whether the next token is an x. When true, this would indicate that xfl replaces to an x. And yet, if I do a
detokenizeexpandafter{xfl}
I do not get an x as I would expect, but only an unexpandable xfl.
Why is that? Are there other tests I can perform than ifx on a futureletted token? Can't I truly capture (and save) that token?
documentclass{article}
usepackage[T1]{fontenc}
deffltest{futureletxflpdecide}
defpdecide{%
ifxxfl xrelax[Next character is x]else[Not x]fipar
(Can't detokenizedetokenizeexpandafter{xfl})par
}
begin{document}
fltest xyz
end{document}
tex-core
tex-core
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
asked 5 mins ago
Steven B. SegletesSteven B. Segletes
154k9198405
154k9198405
add a comment |
add a comment |
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