Re: Returning rules from functions inside a package context

*To*: mathgroup at smc.vnet.net*Subject*: [mg82494] Re: Returning rules from functions inside a package context*From*: Art <grenander at gmail.com>*Date*: Mon, 22 Oct 2007 05:39:43 -0400 (EDT)*Organization*: University of California, Berkeley*References*: <ff9rjl$4mv$1@smc.vnet.net> <ffedit$bjv$1@smc.vnet.net>

On Sun, 21 Oct 2007 02:29:49 +0000, Vince Virgilio wrote: > On Oct 19, 4:58 am, Art <grenan... at gmail.com> wrote: >> The following question has been asked and answered in a variety of ways >> in this forum, but I am new to Mathematica and am still not sure what >> is best practice after doing Trace of various trivial statements for >> the past few hours. >> >> For example, I would like f[] below to return {a->1.}, not >> {A`Private`a->1.}. >> >> BeginPackage["A`"] >> f::usage = "" >> Begin["`Private`"] >> >> f[] := FindFit[{{0, 0}, {1, 1}}, a x, {a}, x] >> >> End[] >> >> EndPackage[] >> >> The use of Rule[] in different scoping constructs is confusing. >> >> Thanks. > > First scope a and x appropriately, as others in this thread have > advised. > > But then try strings; return the value with the definition f["a"] = 1, > or if you need rules, perhaps f["a"] = {"a" -> 1}. > > I think it's prudent to keep the symbols to a minimum; they too easily > introduce difficult dependencies into larger packages. > > Vince Virgilio Thanks for all the different suggestions. I have a much better idea now, though it took me a while. I am following Jens-Peer's suggestion of defining usage for the each of the returned rule symbols. I am guessing that will be the easiest way for me to stay out of trouble (and giving Capitalized long names to everything). I find, though, that I am parsing the options strings a lot with Cases[opts, Rule[x_, y_]-> something] which may be a bad habit. Art