I am trying to \"translate\" the flowing vanilla makefile lines into CMake syntax.
SRCS = $(wildcard *.foo)
OBJS = $(SRCS:.foo=.bar)
my_rule: $(OBJS)
%.bar
Your attempt is correct, and it hardly can be significantly improved.
This is just how CMake works: each of its "rules" is concrete; you cannot create a "template rule". The reason for that is platform independence: not every build systems supports "templates" for rules.
On the other side, CMake supports creation of the "rules" within functions/macros. So typing repeated parts can be easily reduced.