Applesoft BASIC also only supported numeric single line functions. The first BASIC I used was Tandy TRS-80 Level II BASIC which shipped on all but the earliest

Applesoft BASIC also only supported numeric single line functions. The first BASIC I used was Tandy TRS-80 Level II BASIC which shipped on all but the earliest of the TRS-80 Model I's. Microsoft wrote this BASIC also and it didn't support any type of user defined functions. Microsoft created a Level III BASIC for the TRS-80 which was their first consumer product. This did support single line functions and I think but am not absolutely sure that it supported string as well as numeric functions.