qsp_parser/documentation/parsing.md

Reading QSP

The QSP language was not designed to be processed in this way. There are ambivalent cases that cannot be represented cleanly via a grammar.

An example is the ! character, which can indicate the start of a comment, or an inequality operator.

Another example is the * character, which can be the first character of an instruction, or a multiplication operation. For example:

• *clr() is a valid instruction, but 5 *clr() is not.
• *rnd() is an invalid instruction, but 5 *rnd() is valid. (As a bonus rnd* rnd() is also valid…)

What's more, the language is very permissive, allowing for structures that are actually incorrect.

For example:

if $PARGS[0] = 'Day1':
end

elseif $ARGS[0] = 'Week1':
end

As a result, the application may pick up errors on particular cases that are nonetheless valid. I've tried to respect the syntax of the QSP language as much as possible, but on borderline cases, I consider that being stricter is positive.