While hash tables are useful for large symbol tables, the bool "enum" is
too small to justify one and even bsearch is too expensive (also,
bsearch requires knowing the number of elements, which is a bit of a
hassle currently).
The string type is useful for passing around strings (the only thing
that they can do, currently), particularly as arguments to functions.
The voidptr type is (currently) never generated by the core cexpr
system, but is useful for storing pointers via cexpr (probably a bit of
a hack, but it seems to work well in my current use).
At least with a push-parser, by the time the parser has figured out it
has an identifier, the lexer has forgotten the token, thus the annoying
and uninformative "undefined identifier " error messages. Since
identifiers should always have a value (and functions need a function
type), setting up a dummy symbol with just the identifier name
duplicated seems to do the trick. It is a bit wasteful of memory if
there are a lot of such errors between cmem resets, though.
The prefix gives more context to the error messages, making the system a
lot easier to use (it was especially helpful when getting my cvar revamp
into shape).
cexpr's symbol tables currently aren't readily extended, and dynamic
scoping is usually a good thing anyway. The chain of contexts is walked
when a symbol is not found in the current context's symtab, but minor
efforts are made to avoid checking the same symtab twice (usually cased
by cloning a context but not updating the symtab).
The generated short names for a lot of Vulkan enums start with a number
(eg VK_IMAGE_TYPE_2D -> 2d). Having to prefix the short name with ` is a
tiny cost for the convenience.
It is capable of parsing single expressions with fairly simple
operations. It current supports ints, enums, cvars and (external) data
structs. It is also thread-safe (in theory, needs proper testing) and
the memory it uses can be mass-freed.
