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Please use this page to document all the ideas and wishes you'd like to see in Groovy.

  • Support standard for statement. (Note: supported by the JSR grammar.)
    e.g. for (int i = 0; i < 5; ++i)
    {... I don't know whether the standard for statement is still not implemented till beta-10, or Groovy will not support it in 1.0 release.
  • New function for integers to reverse bits.
  • Concatenate string with null object.  'Test'+null will produce 'Test'.
  • Function/Global method 'NVL'. This method avoid null/empty string value of object. E.g. NVL(null,'Test')='Test' and NVL('','Test')='Test'
  • Joining of list without null elements.

         e.g. [null,'Hello','world',null].join(' ') will produce 'Hello world'

  •  Simple and Robust way of executing external processes instead of using ProcessBuilder. Make the convenient string.execute() handle blocked IO streams / threading so users are not required know or understand about ProcessBuilder
  • Import Static.  Just like in Java 1.5.
  • More Enumerable methods for lists, arrays and maps (like map, pluck, invoke, ...)
  • Make logical operators (||, &&...) return the value instead of the boolean equivalent
  • Make map creation more versatile Add constructors that allow creation of a map from 2 collections "HashMap(keys, values)" or a list of entries "HashMap(itemlist)".

  • Make a list and create an auto mapping:


  • would like methods to return more than one return value (a la ruby)

Property reference operator

Groovy 1.0 already has the method reference operator:

However we do not have anything similar for properties. i.e. we should be able to get a reference to a wrapper object for any object property, and be able to get and set the property via the reference, and get the original property name and owning bean:

This would be useful in Grails and other apps that need the user to specify in their code a reference to another propery, for example in GORM declaring the list of "embedded" properties:

class AddressBookEntry

Property access in groovy is not problematic using GPath or subscript operator anyway, so this may not seem so useful. However if we could get some compile-time checking of the validity of the property that would be a nice win. Perhaps combining with the @ operator:

Altho a tad heiroglyphic, this would allow the compiler to ensure that "home" and "work" do exist as declared properties on the class or its ancestors, and hence fail fast.

named parameters everywhere

the proposal is that for functions defined inside groovy or where the debug information is availlable can be called with the map construct to provide named parameter calling everywhere 

this feature would largely improve general readability of code and imho very often enough information should be availlable to perform the matching (certainly for groovy functions, very often for java binaries with appropriate debug information)

smarter nulls

should print "hello" iso "hellonull"

variable constraints

Keep dynamic typing while adding real type safety with constraints on variables that all must be true.  Though not all these constraints are actually useful they are there for illustrative purposes.

Embedded XML

The programming language Scala has built-in support for XML. You can create something like this (taken from the Scala overview document):

 Decoupling of static and instance methods

Also taken from the Scala programming language. It doesn't have static methods. All the static methods should be placed in a singleton. Static members are not a part of instance variables, so you shouldn't have to declare them in the same class.

 New way of declaring Expando

Could be just like in annonymous types in C#. For example:

First Class Support for User-Defined Boolean Types

There is already quite good support for user-defined numeric data (e.g. classes that act like numeric data in expressions) using the current support for operator overloading.  But if one needs to define a class that operates in expressions like a Boolean, it can't be done.  The following changes would make this possible and these seem consistent with the overall idea and design of Groovy:

  1. Enable operator overloading for logical AND, logical OR, logical NOT. For logical AND and logical OR, the deferred evaluation of the right operand can be maintained by passing a Closure to the method.  The signatures might be something like this:
  2. Enable assignment operator overloading.  This is needed to allow a semantic like
    Note that overriding the assignment operator makes it significantly easier to replace numeric types too since one can handle cases like
    which is not possible today.
  3. Today due to "Groovy Truth" processing, any non-null object reference (that is not a Boolean) will evaluate to true.  To enable user-defined Boolean type data, Groovy Truth would need to be modified to optionally "unbox" a non-null object reference into a Boolean value if it has a booleanValue() method.  This would allow one to do something like this
    In such a case, the bool instance can be either false or true and can be directly used for control flow and other operations that normally expect a Boolean.
    With these changes, user-defined boolean replacement classes would get first-class support in the language.

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