Add ability to exclude function(s) from a trace or report about piggly

[kputnam]

This can be accomplished with the current command line options, though it's tricky. I will propose an improvement in the next comment.

For instance to trace everything but procs whose name begins with "bad" or "old". This says "don't move past the first character ^ and fail if (bad|old) matches".

$ piggly trace --pattern '/^(?!bad|old)/'

Then to trace everything except procs whose name ends with "bad" or "old".

$ piggly trace --pattern '/(?!bad|old)...$/'

This shows how it starts to get complicated, and rejecting names that match somewhere between the start and end, like "an_old_proc" is much worse.

[kputnam]

I think the commands should have options like --select and --ignore, and apply them in the order they were passed. That is, --ignore A --select B will ignore procedure names matching A unless it matches B. When passed --select B --ignore A procedure names matching B are selected unless it matches A.

Multiple options are additive so --select A --select B means "select anything matching A or B". Then --ignore X --ignore Y means "ignore anything that maches X or Y".

I don't like making it more complicated, but I think it remains simple for simple cases, and it makes complicated things possible.

[kputnam]

Note currently the matches aren't performed against the schema name, just the procedure name. This will also be addressed.

[lcoldiron]

Seems like a reasonable compromise to me.

[kputnam]

Note I also added --dry-run to each command to print which procedures matched your filters. Filters can be exact string matches like --select 'public.foo' or regular expressions like --select '/public\./'.