A lil help w/ Substrings

[KuJi]

Well.. heres whats up:
makevar("test." @ tokens[0]) = "hi";
tokens[0] contains of test.a=B

so I would need it to look like this:
makevar("test.a") = "B"; (test.a = B)

Normally I could just substirng it, but the tokens could always change. How can I detect where the = is and get the content before and after the sign?

Thanks.