Allocating and freeing memory blocks

[RichardRussell]

Ok, so your interpreter has algorithms in place which detects string space getting freed and the ability to re-use it.

You make it sound unusual or noteworthy, but pretty much every BASIC interpreter does something similar. It's true that some early versions of BBC BASIC (e.g. the 8-bit 6502 and Z80 versions) had such a simplistic string allocation strategy that the memory occupied by a string could never be reused, but Acorn's ARM BASIC, Brandy, BBC BASIC for Windows and BBC BASIC for SDL 2.0 all allow memory freed by one string to be reused by another string. So this has been a feature of BBC BASIC since 1984 or thereabouts!