How to make bash alias invocation conditional on PWD?

I currently have this alias:

alias cmakerel='cmake -DCMAKE_BUILD_TYPE=Release -Wno-dev ../../ && make -j4'

Essentially, it will call cmake to do an out-of-source build from PWD. It works fine, but as-is, it can be run from nearly anywhere (which I don't want).

How do I modify this alias so that it runs if and only if the string bld is in my present working directory?

I need this change because without it, I sometimes accidentally invoke this command from the tst directory or some other directory where I just cause a total mess.

Answer

From man bash:

For almost every purpose, aliases are superseded by shell functions.

So make it a shell function.

function cmakerel {
    if expr match "$PWD" '.*bld.*' >/dev/null ; then
        cmake -D....
    else
        echo "Wrong directory!"
    fi
}

It's a regular expression you can adjust to your needs.