Full solution for today (spoilers!).
The input is a list of pairs of the form
a|bwhich defines thatbmust not come beforea, an empty line, and then a list of valuesa,b,c,d.For each line that is valid for all given
a|brules, sum the middle number of each list.
It’s been a bit, but I hope it’s worth it. StackLang, part 5: compiling to C!
StackLang, part 4: an interpreter. Here we go again!
This time, the goal is to actually get code running
StackLang, part 3: parsing. This is going to be the most complicated one thus far! Onward.
StackLang, part 2: lexing.
It’s quite often the simplest part of implementing a programming language (although parsers for s-expression based languages come close), but it’s still something that needs done. So here we go!
I enjoy writing programming languages. Example: Tiny. Let’s do that again.
This time, StackLang:
{
@[n fact]
1
{ n 1 - $fact fact n * }
N 1 <= if
} @fact
5 $fact fact writeln
Bit of gibberish there, I suppose, but the goal is to write everything in a postfix/stack based model. So n 1 - $fact fact n * is equivalent to fact(fact, n - 1) * n in a more traditional language.
Over the next few posts, I hope to write up where I am thus far and what’s next.