mparser: lexer: reduce regular expression usage

Match single-character tokens a separate dictionary lookup.
As pointed out by dcbaker, this is even faster than str.index
and gives the syntax error check for free (via KeyError).
It also enables splitting the special-case "if" in two parts, one
for long tokens and one for short tokens, thus providing further
speedup.

This shaves about 2/3rds of the time spent in lex().

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

0 files changed, 0 insertions, 0 deletions