Generate a PostScript syntactic chart image of the buffer in an EPS file.
Generate an EPS file for each production in the buffer.
The EPS file name has the following form:
The default value is "ebnf--".
Some characters in the production file name are replaced to
produce a valid file name. For example, the production name
"A/B + C" is modified to produce "A_B_+_C", and the EPS
file name used in this case will be "ebnf--A_B_+_C.eps".
WARNING: This function does *NOT* ask any confirmation to override existing files. (fn)