[#BOO-818] Shorthand syntax for Nullable of T, like T? in C#.

Boo

Shorthand syntax for Nullable of T, like T? in C#.

Created: 30/Apr/07 04:07 AM Updated: 06/Apr/08 08:51 AM

Component/s:

Parser, Compiler

Affects Version/s:

None

Fix Version/s:

0.8.2

Time Tracking:

Not Specified

Issue Links:

Related

This issue is related to:

~~BOO-619~~ Shortcuts to interfaces

Description

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Here's the JIRA discussion about Avish suggestion.

If approved we would get a shortcut syntax as in C# to declare nullable types.

Example:
x = int?

instead of :
x = Nullable of int

All

Comments

Work Log

Change History

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Marcus Griep - 29/Oct/07 10:20 PM

For generic structs, the '?' should come before the generic parameters as in:

x = test? of int
x = tester?[of test? of int, char]

Otherwise the following code becomes ambiguous (possibilities in comments):

x = test of int?
// x = test[of int?]
// x = test[of int]?

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Rodrigo B. de Oliveira - 30/Oct/07 04:52 AM

x = test of int?

should always means:

x = test[of int?]

Disambiguation should be done through [] as in:

x = test[of int]?

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Marcus Griep - 30/Oct/07 08:22 AM

Would you then prefer the '?' to be after generic parameters rather than before?

x = test? of int
x = test[of int]?

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Cedric Vivier - 02/Apr/08 08:43 AM

Since we have discussed about removing syntax without brackets for 0.9 (constraints...) the choices are clearer :

1) x = test?[of int]

2) x = test[of int]?

I also have a preference for (1) since imho "nested nullables" looks clearer with it, compare :

(1) x = test?[of int?]

against

(2) x = test[of int?]?

Marcus I'm willing to work on this soon along with ~~BOO-805~~ / ~~BOO-807~~ , so would you mind reassigning the task to myself?

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Marcus Griep - 02/Apr/08 11:55 AM

I would not have a problem with you taking a couple issues. I haven't gotten around to this one, so its better to get this one rolling.

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Rodrigo B. de Oliveira - 02/Apr/08 12:03 PM

For consistency, the '?' should always come after the type reference.

x = test[of int?]?

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Cedric Vivier - 02/Apr/08 01:25 PM

Good point!
Consistency with C# syntax is not bad either.

Well, let's go for this syntax then.

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Cedric Vivier - 06/Apr/08 08:51 AM

fixed in rev. 2897

some antl-fu is needed to re-enable ID_PREFIX '?' for brail users.