Re: Interactive parsing with Bison

[Paul Eggert]

Richard Stallman <address@hidden> writes:

>     But Bison itself is already "incredibly slow", due to its M4 component.
>
> What is this?

Bison currently uses M4 to process parser skeletons before outputting
them.  Formerly this processing was done by hand in C code, in Bison,
but this was painful to maintain as we added more functionality.  M4
is slow, and scales poorly, but we didn't think efficiency during
parser generation was all that important, and we didn't think people
would be generating parsers with millions of states.