I've been combing through the CMake documentation for a while now trying to figure out why some function arguments are capitalised and some aren't. I was hoping someone might be able to explain the pattern of things being capitalised, or at the very least point me in the direction of the documentation. This documentation https://cmake.org/cmake/help/v3.0/manual/cmake-language.7.html#cmake-language-7 gives very little in the way of explaining why certain things are capitalised.
From my current understanding, uppercase arguments can be:
Lowercase arguments are:
Here's an example of a CMake file which you can maybe help me dissect?
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
include(SomeLib)
include_directories(include)
add_library(mylib SHARED src/main.cpp)
target_link_libraries(mylib ${boost_LIBRARIES})
install(TARGETS mylib DESTINATION lib)
VERSION I'm guessing is a keyword,
SHARED is probably also a keyword, or possibly a property,
TARGETS and DESTINATION are also keywords?
There is no some accepted style for writing CMake code so you can encounter anything. What you usually see is a historical somewhat accepted style used by the devs (Kitware) which was adopted by many others.
Usually you use lower case for CMake command, macro and function names, so to correct your code you need to lower case for the version command: cmake_minimum_required(VERSION 2.8) because it is a command.
Some commands have named arguments, some not. Usually named arguments are in upper case. In your example TARGETS, VERSION, SHARED and DESTINATION are all named arguments (which CMake calls keywords). They can be of any case but we just used to make them uppercase. Such arguments got parsed with the cmake_parse_arguments help for functions & macros. Since all commands are implemented in C++ the argument parsing is done in C++ for them (probably with the same "command").
Apart from the command names, lower case might be used in functions for local variables but that's not established and you can find any kind of mixing in the wild.