Bug in Default[] or Bug in My Understanding?

*To*: mathgroup at smc.vnet.net*Subject*: [mg89201] Bug in Default[] or Bug in My Understanding?*From*: Salvatore Mangano <smangano at into-technology.com>*Date*: Thu, 29 May 2008 07:03:42 -0400 (EDT)

In[208]:= ClearAll[f] ; Default[f,2] = 0; In[210]:= f[a_, b_.] := a + b In[211]:= f[1] Out[211]= 1 In[212]:= (* Now change Default *) Default[f,2] = 1; (* Note that Mathematica seems to recognize change *) In[213]:= ?f Global`f f[a_,b_.]:=a+b f/:Default[f,2]=1 (* But not really! Expected 2 *) In[214]:= f[1] Out[214]= 1 Even if it is a rule that you can't change the Default after the function is defined it is certainly not nice of Mathematica to allow such a change and advertise the change in the output of Definition[] and Information[]. I am using 6.0.2.0 on Windows XP.

**Follow-Ups**:**Re: Bug in Default[] or Bug in My Understanding?***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>