Gracefully fallback for bit libraries

[daurnimator]

How can I gracefully fallback with bit libraries and luarocks?

I wrote some code that works with lua 5.3 or luabitop.
But luabitop won't compile with lua 5.3.
So it looks like I can't support all lua versions with the one rockspec?

(output from https://travis-ci.org/daurnimator/lua-http/jobs/54412346#L523 )

Using https://rocks.moonscript.org/luabitop-1.0.2-1.src.rock... switching to 'build' mode
gcc -O2 -fPIC -I/usr/local/include -c bit.c -o bit.o
bit.c: In function ‘barg’:
bit.c:83:2: error: #error "Unknown number type, check LUA_NUMBER_* in luaconf.h"
Error: Failed installing dependency: https://rocks.moonscript.org/luabitop-1.0.2-1.src.rock - Build error: Failed compiling object bit.o

[siffiejoe]

Use two different rockspecs (one for Lua 5.3 without luabitop in the dependencies, and one for Lua 5.1/5.2 with luabitop), or use bit32 instead of luabitop. bit32 is available for Lua 5.1, 5.2, and 5.3.

[daurnimator]

looks like I can't support all lua versions with the one rockspec?

---

Use two different rockspecs (one for Lua 5.3 without luabitop in the dependencies, and one for Lua 5.1/5.2 with luabitop)

So: yep :p

use bit32 instead of luabitop. bit32 is available for Lua 5.1, 5.2, and 5.3.

ah ha! this might save me for now.