Re: ClearAll error message
- To: mathgroup at smc.vnet.net
- Subject: [mg92389] Re: ClearAll error message
- From: carlos at Colorado.EDU
- Date: Tue, 30 Sep 2008 07:35:41 -0400 (EDT)
- References: <gbnpep$pr3$1@smc.vnet.net> <gbqcv3$ebb$1@smc.vnet.net>
Actually this was not a big deal. The group working with the program was
puzzled by the message but soon it was fixed. BTW, one student came
with an elegant one-liner to create a nxn symmetric array:
S=Table[rootname[Min[i,j],Max[i,j]],{i,n},{j,n}]
The Clear behavior seems largely a question of esthetics. One of the basic
rules of functional programming is function composition equivalence:
y:=f(x); z:=g(y) equiv z:=g(f(x))
Since name=Symbol["A"]; ClearAll[name] is not equivalent
to ClearAll[Symbol["A"]] the rule is violated here, and likewise
for any function with HoldAll attribute. Correct?