Passing variable to be evaluated in groovy gstring - groovy

Question

I am wondering if I can pass variable to be evaluated as String inside gstring evaluation.
simplest example will be some thing like
def var ='person.lName'
def value = "${var}"
println(value)
I am looking to get output the value of lastName in the person instance. As a last resort I can use reflection, but wondering there should be some thing simpler in groovy, that I am not aware of.

Answer 1

Can you try:
def var = Eval.me( 'new Date()' )
In place of the first line in your example.
The Eval class is documented here
edit
I am guessing (from your updated question) that you have a person variable, and then people are passing in a String like person.lName , and you want to return the lName property of that class?
Can you try something like this using GroovyShell?
// Assuming we have a Person class
class Person {
String fName
String lName
}
// And a variable 'person' stored in the binding of the script
person = new Person( fName:'tim', lName:'yates' )
// And given a command string to execute
def commandString = 'person.lName'
GroovyShell shell = new GroovyShell( binding )
def result = shell.evaluate( commandString )
Or this, using direct string parsing and property access
// Assuming we have a Person class
class Person {
String fName
String lName
}
// And a variable 'person' stored in the binding of the script
person = new Person( fName:'tim', lName:'yates' )
// And given a command string to execute
def commandString = 'person.lName'
// Split the command string into a list based on '.', and inject starting with null
def result = commandString.split( /\./ ).inject( null ) { curr, prop ->
// if curr is null, then return the property from the binding
// Otherwise try to get the given property from the curr object
curr?."$prop" ?: binding[ prop ]
}