Groovy DSL - shortcut for creating objects - groovy

Question

is there a way in Groovy to replace some code like the below:
Task a = new Task('a')
Process p = new Process('p')
with something easier, like:
task a
process p
where task and process can be method calls that create the object and return it or add it to the script Map.
The main problem I currently have is that I cannot use a because it is not defined.

Answer 1

To create objects and name them without assigning to a variable, you can use a binding. Create and keep a reference to the a closure's binding, and have the utility methods task and process associate the new instance with the name. For example:
def scriptBinding = new Binding()
def task = { String name ->
scriptBinding[name] = new Task(name)
}
def process = { String name ->
scriptBinding[name] = new Process(name)
}
def script = {
task 'a'
process 'b'
println a
println b
}
script.binding = scriptBinding
script()
Note that you have to quote a and b so they are interpreted as strings instead of undefined variables. If you'd like to omit quotes, you can use a custom Binding object that evaluates undefined symbols as their string representation like this:
class SymbolAsStringBinding extends Binding {
Object getVariable(String name) {
try {
super.getVariable(name)
} catch (MissingPropertyException e) {
name
}
}
boolean hasVariable(String name) {
true
}
}
With that addition, you can write the script as:
def script = {
task a
process b
println a
println b
}

Answer 2

Try this:
class Task {
String name
Task(name) { this.name = name }
String toString() { "task: $name".toString() }
}
def propertyMissing(String name) { this.getBinding()[name] = name }
def task(name) { this.getBinding()[name] = new Task(name) }
task a
println a
this will produce:
task: a
essentially when you reach the
task a
statement the propertyMissing() will put in the binding a variable named a with content it's name.
Later the task() function will replace the variable a in the binding with the new Task passing as name the name of the missing varible a