not hitting any more bugs so far, so i'm writing tests to check if rules work as intended, and also as demo.

here for example are sxpp rules which transform infix expressions into prefix expressions.

(1 * 2 + 3 * 4 + 5 * 6) -> (add (add (mul 1 2) (mul 3 4)) (mul 5 6))

(foo bar * fizz buzz) -> (mul (foo bar) (fizz buzz))

#devlog #libsxpp

pattern matching is beginning to work again. the next issue is with variadic patterns. they're not being matched. nothing crashes so this is harder to figure out...

found it through comparing with the original source.

when a matching thread is done (not a real thread, just a simulated one), the loop is supposed to skip to the next thread, but it jumps out of the loop to the end of the parent loop, skipping processing of all following threads. that was a mistranslation.

#devlog #libsxpp

i now found the cause for the first big bug:

months ago i made a tiny change in symbol unescaping, deciding that unknown escapes would strip the backslash (e.g. \$ becomes $).

but the rules parser depends on \$ to be passed as-is, so variable names can be escaped.

because that didn't happen, all fundamental forms, which start with \$, turned into variables, and so the first of any rule would be applied and eat the entire source file this way.

this took a whole day.

#devlog #libsxpp