Eric S. Raymond
esr at thyrsus.com
Tue Jun 19 18:28:23 UTC 2018
Hal Murray <hmurray at megapathdsl.net>:
> esr at thyrsus.com said:
> > What I think one needs for a test harness is the ability to dump the parse
> > tree structure in a textual form. Changing parser generators won't give us
> > that. What really matters is whether our target language has introspection
> > capability and dynamic dump code.
> Is there a parse tree? I thought the parser called out when it had enough
> info to build a chunk of the tree. I think that chunk is either a final leaf
> node or one level up, a node with several parameters.
How deep the parse tree goes before a call-out varies depending on
what part of the configuration you're looking at. You're right, there
isn't one big parse tree. I spoke loosely.
> My expectation is that we would write a collection of dummy called-out
> routines that printed out the parameters rather than building ntpd's
> equivalent of a chunk of the parse tree.
I thought about that back when I was looking at this code. Concluded
it wouldn't be that useful to (effectively) just dump the input tokens
with a slightly different syntax.
If you think this was a mistake, I'm open to argument.
> >> When we ripped that stuff out, why didn't we add something better?
> > Because it wasn't actually used in the unit tests anywhere. I concluded from
> > this that it was probably broken and nobody had had the round tuits to fix it
> > or remove it. So I removed it.
> There was a script that fed it a config file, wrote it out, and diffed them.
> It wasn't integrated with either the test harness or with waf check, but it
I didn't know that.
Still, the fact that it wasn't integrated into the regular tests gives
me to doubt that the capability was actually useful. And...It didn't *look*
like good code; it looked like an over-clever, over-elaborate hack. That
kind of thing always makes my delete finger itchy.
<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
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