An exercise in reflection and an unusual tool.

From the usage message:

usage: gotry [packagedirectory] expression ...
Given one expression, gotry attempts to evaluate that expression.
Given multiple expressions, gotry treats them as a list of arguments
and result values and attempts to find a function in the package
that, given the first few expressions as arguments, evaluates to
the remaining expressions as results.  If the first expression has
methods, it will also search for applicable methods.

If there are multiple expressions, a package directory must be
specified. If there is a package argument, the expressions are
evaluated in an environment that includes
	import . "packagedirectory"

Examples:
	gotry 3+4
		# evaluates to 7
	gotry strings '"abc"' '"c"' 7-5
		# finds strings.Index etc.
	gotry regexp 'MustCompile("^[0-9]+")' '"12345"' true
		# finds Regexp.MatchString

R=rsc, PeterGo, r2
CC=golang-dev
https://golang.org/cl/2352043