Lua expressions, and commands simply allow a shorthand that generates
valid Lua expressions. Make strings Lua expressions.
This essentially reverses strings; rather than:
Metric1=Text
Metric2=@Text()
specify:
Metric1="Text"
Metric2=Text()
This means that every metric (except Fallback, currently) can be
treated as a Lua expression, except for Command metrics that just
need a bit of preprocessing.
Glenn Maynard
f90088d616