dynamic parsers re parser generators

I used dynamic as a term to describe the behaviour of a parser that
can adapt to its input. One example of such an input is a phrase in
the grammar describing the input that follows. Example (although these
examples may refer to the lexical analysis part of a parsing process):


% line commented with default comment character
...
comment_character #
...
# line commented using the "new" comment character
...




Or another example:
"String using \\ as an escape character\n"
...
escape_character %
...
"String using % as an escape character%n"
...
Question:
Is there any parser generator/lexical analyzer that delivers this
functionality and produces C/C++ (portable) code?


TIA,
JF
[There was a lot of work in extensible languages in the 1970s, but I
don't know anyone doing it any more. It's technically not all that hard,
but turns out not to be very useful. -John]

Return to the comp.compilers page.
Search the comp.compilers archives again.