After the clarification I would also recommend and approach along the
line of waiting until the binding actually tries to access an unbound
variable and evaluate its value then (since the name of the variables is
not actually needed for anything else)...
On 26.11.2017 19:47, Marcin Erdmann wrote:
Wouldn't it be easier for you then to implement a class which extends
groovy.lang.Binding which lazy evaluates your default variables and
use that as your script binding instead?
On Sun, Nov 26, 2017 at 6:26 PM, bayareagreg <bayareag...@gmail.com
<mailto:bayareag...@gmail.com>> wrote:
All right, let me explain why I need this.
In my product, we let our users evaluate "custom" groovy
expressions they
construct. This is done in Java via groovy Script object. There
are half a
dozen "standard" product variables users can refer to in those
expressions.
The values of these variables are bound into Bindings object
before the
script is run. The values may be a String, a GPathResult, a
java.util.Map,
etc. The problem is that some of the variables are quite expensive to
compute and it is a waste of time to do so if the expression does not
reference these variables.
For example, if the expression happens to be "${x}", I would be
nice to only
compute the value of x and bind it before invoking the script, not
y, z, w,
etc.
That is why I was wondering if there was a simple way to get the
list of all
variables used in an expression. Another way to solve the problem
would be
some kind of "lazy evaluation" approach where we would bind all
variables to
some type of "proxy" object, such that the real values are only
computed on
"as needed" basis. I could not find an easy way to do that either.
Some
pointers would be very much appreciated
Thanks in advance
Greg
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