René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Suggestion: implement null-coalescing, null-conditional access (null-soaking), null-conditional assignment","articleBody":"**Null-coalescing** and **null-conditonal access** (null-soaking) would be handy additions to the language.\r\n\r\n_Update_: @BrucePay  additionally suggests **null-conditional _assignment_**, with `?=` - see [comment below](https://github.com/PowerShell/PowerShell/issues/3240#issuecomment-417435164).\r\n\r\nFor instance, instead of writing:\r\n\r\n```powershell\r\nif ($null -ne $varThatMayBeNull) { $varThatMayBeNull } else { $fallbackValue }\r\n#\r\nif ($null -ne $varThatMayBeNull) { $varThatMayBeNull.Name } else { $null }\r\n```\r\n\r\none might be able to write:\r\n\r\n```powershell\r\n$varThatMayBeNull ?? $fallbackValue  # null-coalescing\r\n# \r\n$varThatMayBeNull?.Name   # null-conditional access, for Set-StrictMode -Version 2+\r\n$varThatMayBeNull?[42]  # ditto, with indexing\r\n```\r\n\r\nRe null-conditional access: With `Set-StrictMode` being OFF (the default), you can just use `$varThatMayBeNull.Name` - no special syntax needed; however, if `Set-StrictMode -Version 2` or higher is in effect, `$varThatMayBeNull.Name` would _break_ and that's where the null-conditional operator (`?.`) is helpful, to signal the explicit intent to ignore the `$null` in a concise manner.\r\n\r\n---\r\n\r\n**Open question**:\r\n\r\n`$varThatMayBeNull?[42]` handles the case where the variable is `$null`, but if it isn't, an array element with the specified index _must exist_.\r\n\r\nIt would therefore also be helpful to **make _indexing_ null-conditional** - something that C# does _not_ support, incidentally (you have to use `.ElementAtOrDefault()`).\r\n\r\nThe two basic choices are:\r\n\r\n* Come up with additional syntax that explicitly signal the intent to ignore a non-existent _index_:\r\n\r\n  * The question is what syntax to choose for this, given that `?[...]` and `[...]?` are not an option due to ambiguity. \r\n  * Perhaps `[...?]`, but that seems awkward .\r\n\r\n* Rely on the existing behavior with respect to accessing non-existent indices, as implied by the `Set-StrictMode` setting - see [table below](https://github.com/PowerShell/PowerShell/issues/3240#issuecomment-478599343).\r\n\r\n---\r\n\r\nRelated:  [implement ternary conditionals](https://github.com/PowerShell/PowerShell/issues/3239)","author":{"url":"https://github.com/mklement0","@type":"Person","name":"mklement0"},"datePublished":"2017-03-02T20:28:43.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":71},"url":"https://github.com/3240/PowerShell/issues/3240"}