Why the statement expression instead of an inline function?

Why not use a hashing algorithm, instead? Your source generator could scan the strings of interest and make symbols whose values are their hashes. Then, assuming that compute_hash() has exactly the same algorithm as your code generator:

switch (compute_hash(“foo”)) {
case STRING_FOO_HASH: … ;
case STRING_BAR_HASH: … ;
}

Now you walk the string exactly once at runtime, to compute the hash, instead of doing logN comparisons in a bsearch.

A disadvantage is that your syntax of case SOMETHING(string_i_want_to_match) is more obvious, but it would remove the limitation of word-characters (which is a reason i can’t apply your idea to my own problem ;-).

For that matter, you might just have a nice, intrinsically extensible hash table of string->handler function, but that’s nowhere near as syntactically friendly as a switch statement…

for gperf and why it’s not suitable, see:
http://shum.huji.ac.il/~agay/sos/theory.html#gperf
in short, it has unwanted collisions with arbitrary strings and it’d involve a hell of a lot more code then the simple binary lookup SOSID has.