Re: Best practice passing expressions to functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg85317] Re: Best practice passing expressions to functions*From*: Grischika at mail.ru*Date*: Tue, 5 Feb 2008 19:47:47 -0500 (EST)*References*: <fo9gvu$t1l$1@smc.vnet.net>

On 5 =C6=C5=D7, 13:23, Remo Aschwanden <rca... at yahoo.com> wrote: > Hi > > I want to write procedures that accept expressions as parameters and be > able define functions based on these expressions, i.e. > > f[exp_]:=Module[ > =9A =9A"g[x_] := exp " > ] > > The code between the " " should clarify what I intend to do. Calling > =9A =9Af[x^2-2x+4] > should lead to the definition of a function (or pattern) > =9A =9Ag[x_]:=x^2-2x+4; > > What's the best way to do this? How can I do this without being > dependent on the variables used in the expressions ("x")? > > Thank you. > Remo A. Hello. Try this defenition: f[exp_, v_: x] := Module[{}, g = Function[x, exp /. v -> x]] In[31]:= f[x^2 + c, c] Out[31]= Function[x$, c + x^2 /.c -> x$] In[32]:= g[2] Out[32]= 2 + x^2 In[33]:= f[x^2 + c] Out[33]= Function[x$, c + x^2 /.x -> x$] In[34]:= g[2] Out[34]= 4 + c I do not know if it possible to avoid rule replacement in function definition.