I chose C because:
With respect to indentation, I’m migrating the code to follow Google C++ Style Guide to avoid having to switch styles all the time. The code was originally written using my old style: 4-space indent with 1TBS (One True Brace Style).
I’d like to have no library dependencies (except standard C libraries), but then I’d have to write a large integer library. Furthermore, I’d have to write it in assembly, and then port it.
To avoid this, I use an existing library. I selected GMP because the library’s focus is on multiprecision arithmetic and nothing else, and it aims to be as fast as possible on many platforms. Another important factor is that GMP is released under a free license.
On the other hand, GMP is written to deal with extremely large numbers, while I mostly only need integers that are roughly between 160 and 2048 bits. It is possible a library specializing in numbers of these sizes would be better for PBC.
I’m fond of GMP’s method for eliminating the need for the
operators most of the time by declaring a typedef on arrays of size 1. I try
to do the same with PBC for consistency, though this trick does have drawbacks.
I would like to have GMP as the only library dependency, though I do not mind using other libraries so long as they are optional. For example, one of the test programs is much easier to use if compiled with the GNU readline library, but by default compiles without it and is still functional.
I dislike the C preprocessor. I like to place platform-specific code in
separate files and let the build system work out which one to use. Integer
constants can be defined with enum instead. I intend to minimize the number of
#include statements in header files for PBC’s internal use as much as
possible (they should be in the
.c files instead), and later perhaps even
remove those annoying
#ifndef statements too.
I grudgingly accept some macros for PBC’s debugging features.
I liberally use nested functions, a GNU C extension. I find their expressiveness so indispensable that I’m willing to sacrifice portability for them.
GNU libc manual
states that data types ending in
_t should not be used because they are
reserved for future additions to C or POSIX. On the other hand, I want to stay
consistent with GMP, and ending data types with
_t is common practice.