Re: [classad-users] ClassAd Transform?

[Matthew Farrellee <matt@xxxxxxxxxxx>]

Alain,

Is there a quick method for evaluating a bunch of attributes and 
plugging them into a new ClassAd? I am skimming the API and evaluation 
(i.e. EvaluateAttr) always seems to result in a Value, which then has 
to be inspected (i.e. find out if IsBooleanValue should be called or if 
IsClassAdValue should be called...) before it can be inserted into a 
new ClassAd. is there a simpler way, such as an Insert call on ClassAd 
that takes a Value instead of an ExprTree?

matt

On Jun 2, 2004, at 4:01 PM, Alain Roy wrote:

Matthew Farrellee wrote:
How easily would it be for me to use the new ClassAd library to take 
an
input ClassAd I, a "tranform" ClassAd T, and produce an output ClassAd
O? For example:

I: [A = 2; B = 3;]
T: [A = $(A); B = $(B); C = $(A) * $(B);]
O: [A = 2; B = 3; C = 6;]
Is this a job for CAFL?
There is no easy, automatic way to do this with the new ClassAd 
library. CAFL may be appropriate.

One way to do it is to set up a big ClassAd like this:

[
  input = 0;
  template = 0;
]
Then when you know the input and template, substitute them. They won't 
have $ in them, but would look something like this:

[
  input = [A = 2; B = 3;]
  template = [A = input.A; B = input.B; C = input.A * input.C;
]
Then iterate through the template (using the STL-like functions 
begin() and end() and evaluate each expression, and create a new 
ClassAd.

-alain
Condor Classads Info:
http://www.cs.wisc.edu/condor/classad/