Re: What is a good way of returning a function from a Module[]?

*To*: mathgroup at smc.vnet.net*Subject*: [mg83378] Re: What is a good way of returning a function from a Module[]?*From*: Peter Pein <petsie at dordos.net>*Date*: Sun, 18 Nov 2007 04:59:01 -0500 (EST)*References*: <fhmesn$8pg$1@smc.vnet.net>

Szabolcs Horvát schrieb: > What is an elegant way of returning a function from a Module[]? > > Module[{a, b}, a = 1; b = a+1; (a+b+#)&] does not work because > Function[] holds its arguments. > > The best way I could find was > > Module[{p, q}, p = 1; q = p+1; With[{a = p, b = q}, (a+b+#)&]] > > Is there a nicer/more concise way of doing this? This is a simplified > example, but the important points are: > > 1. The returned function may depend on more than one parameter ('a' and > 'b'; let's forget that in this case their sum could have been computed > inside the Module[]). > > 2. 'a' and 'b' are not calculated independently. The value of 'a' is > needed to find 'b' > > Szabolcs > In Version 5.2: map Evaluate onto the function: Module[{a, b}, a = 1; b = a + 1; Evaluate /@ (a + b + #1 & )] 3 + #1 & This works even for functions with arguments which got names already used in the module: Module[{a, b, x = Pi, y = E}, a = 1; b = a + 1; Evaluate /@ Function[{x, y}, (a + b + x)/ (y - b + a)]] Function[{x$, y$}, (3 + x$)/(-1 + y$)] Peter