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diff --git a/documentation/parsing.md b/documentation/parsing.md new file mode 100644 index 0000000..43d5028 --- /dev/null +++ b/documentation/parsing.md @@ -0,0 +1,34 @@ +# 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. + + |