FAWK: LLMs can write a language interpreter

It's a fun post, and I love language experiments with LLMs (I'm close to hitting the weekly limit of my Claude Max subscription because I have a near-constantly running session working on my Ruby compiler; Claude can fix -- albeit with messy code sometimes -- issues that requires complex tracing of backtraces with gdb, and fix complex parser interactions almost entirely unaided as long as it has a test suite to run).

But here's the Ruby version of one of the scripts:

    BEGIN {
      result = [1, 2, 3, 4, 5]
        .filter {|x| x % 2 == 0 }
        .map {|x| x * x}
        .reduce {|acc,x| acc + x }
     puts "Result: #{result}"
    }

The point being that running a script with the "-n" switch un runs BEGIN/END blocks and puts an implicit "while gets ... end" around the rest. Adding "-a" auto-splits the line like awk. Adding "-p" also prints $_ at the end of each iteration.

So here's a more typical Awk-like experience:

    ruby -pe '$_.upcase!' somefile.txt ($_ has the whole line)

Or:

    ruby -F, -ane '$F[1]' # Extracts the second field field -F sets the default character to split on, and -a adds an implicit $F = $_.split.

That is not to detract from what he's doing because it's fun. But if your goal is just to use a better Awk, then Ruby is usually better Awk, and so, for that matter, is Perl, and for most things where an Awk script doesn't fit on the command line the only reason to really use Awk is that it is more likely to be available.

So I have had to work very hard to use $80 worth of my $250 free Claude code credits. What am I doing wrong?