evaluation
- To: mathgroup at yoda.ncsa.uiuc.edu
- Subject: evaluation
- From: uunet!cello.hpl.hp.com!jacobson
- Date: Fri, 23 Mar 90 08:49:33 PST
Does anyone know how evaluation really works? I submit this example of funny behavior (compressed to single spacing for ease of reading): In[1]:= foo[x_] := BAZZZ /; (Print["hi there"];y===True) In[2]:= a = foo[xxx] hi there Out[2]= foo[xxx] In[3]:= b=a Out[3]= foo[xxx] In[4]:= y=True Out[4]= True In[5]:= c=a Out[5]= foo[xxx] In[6]:= foo[xxx] hi there Out[6]= BAZZZ Output 5, in particular, seems rather peculiar. At that point y is True, so it should be impossible to print anything that matches foo[_]. -- David Jacobson