case change in m4_foreach()

[Robert Boehne]

I'm writing a macro that takes a list of comma-separated arguments and 
then uses m4_foreach
to loop over each argument in the list:

m4_foreach([var_name], [$1]
[
 dnl Body
])

In the body I want to do some string manipulation on
the variables value, making it uppercase and replacing - and . with 
underscores.

The problem is that for any macro that translates text, the argument
is interpreted literally - i.e.

>>  m4_toupper(var_name)
gives
>> VAR_NAME

instead of transforming the value, it transforms the name.

i.e.:
#m4_normalize(tl_cxx_DEP)
ds-11.0
#translit(''tl_cxx_DEP'', "a-z", "A-Z")
''TL_CXX_DEP''
#m4_toupper(tl_cxx_DEP)
TL_CXX_DEP

How can I get the contents of the variable transformed?

Thanks,

Robert Boehne