Does anybody know of a macro (package) which allows you to perform
character substitution/deletion on its argument? A typical things I'd
like are to have calls
[]
which would work so that
\filterspaces {remove the spaces from this}
\replacespaces {replace the spaces in this}{_}
would produce
removethespacesfromthis
replace_the_spaces_in_this
even when used inside other macros.