Date: Fri, 3 Oct 2014 21:13:00 -0700 From: Mark Johnston <markj@FreeBSD.org> To: freebsd-dtrace@FreeBSD.org, dtrace-discuss@lists.dtrace.org Subject: dtrace keywords in postfix expressions Message-ID: <20141004041300.GA21821@charmander.picturesperfect.net>
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Hello,
DTrace has a few keywords which are not keywords in C/C++ (e.g.
"provider"). One annoyance which has come up a few times is the fact
that such keywords cannot be used in expressions which would be valid in
the code being traced. For example, FreeBSD's struct g_consumer contains
a field called "provider", and attempting to run the following snippet of
D results in a syntax error:
fbt::g_vfs_done:entry {printf("%s", stringof(args[0]->bio_from->provider->name));}
I don't see any reason the D grammar can't support this, however. The
patch at [1] attempts to fix this problem by allowing certain keywords
to appear in the place of identifiers in postfix expressions. It's not a
complete solution since it doesn't handle types or probe names, but it's a
start. Any thoughts on this approach?
Thanks!
-Mark
[1] http://people.freebsd.org/~markj/patches/dtrace_keywords.diff
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