Minor nit-pick: an interpreter need not work line-by-line, but rather (more commonly?) AST-node-by-AST-node. This isn't necessarily true for BASIC interpreters

Minor nit-pick: an interpreter need not work line-by-line, but rather (more commonly?) AST-node-by-AST-node. This isn't necessarily true for BASIC interpreters or something resembling assembly, but in general the code is represented as a tree of parsed values by the time the interpreter starts running your code.