data_desk VS cdecl

There are various ways you can do metaprogramming in C. Ryan Fleury's Data Desk is one example of how you can do inspection and introspection: https://github.com/ryanfleury/data_desk. Writing a C program that acts as a pre-compiler for your other C code is another example; you can make your own system for generics that way for example.

For example, in a program like cdecl, if you get:

In the mean time, I still enjoy hacking on various projects such as cdecl and writing my programming blog. Aside from computers, I enjoy gardening, cooking, and hope to do some travel.

In case you’re wondering, these code snippets are from cdecl.

For a larger example, consider cdecl that is a program that can parse a C or C++ declaration (aka, “gibberish”) and explain it in English:

It’s been a while since I first started updating cdecl. From my previous article:

I decided to solve problem 6 myself by adding a feature to cdecl that allows you to #define macros as usual and then expand them where cdecl will print the expansion step-by-step as well as warn about things you might not expect. However, that’s a story for another time.

Additionally, you can use cdecl both to decipher and compose declarations.

Suppose there’s an API you’re using that allows “user data” to be given. In C, this is usually done by passing your data to a void* parameter, for example when visiting the nodes of a red-black tree. Assume we have a tree where the data we store at each node is:

There are many sites giving lots of bit twiddling expressions or functions in C, but none that I've found that give a concise set of bit testing functions, so here is a set I've written. (These are used as part of cdecl.)

I recently discovered a test-case that crashed cdecl: