An Introduction to Expression Evaluation

In the Sinclair 8K ROM program of the ZX80/81 the “expression evaluator” is to be found at 0F55-111Bh (improved 8K ROM) and forms an essential part of the program. A study of the fundamental parts of the “expression evaluator” can be very useful as it enables Basic programmers to understand many of the limitations and quirks of the Sinclair Basic.