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Feature: An alternative approach to handling "null conditional" ops #251

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Oct 20, 2021
Merged

Feature: An alternative approach to handling "null conditional" ops #251

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f4351c6
First pass at an alternative approach to handling "null conditional" …
Nigel-Ecma Apr 5, 2021
f881f34
Update expressions.md
Nigel-Ecma Apr 28, 2021
91fe31b
Update lexical-structure.md
Nigel-Ecma Apr 28, 2021
a98d5d7
Update statements.md
Nigel-Ecma Apr 28, 2021
4ee7b60
Extend grammar of null_conditional_member_access and null_conditional…
Nigel-Ecma May 3, 2021
64659e0
Missed one alternative of unconditional_access_part
Nigel-Ecma May 3, 2021
247e2be
Merge branch 'dotnet:draft-v6' into alt-null-conditional-ops
Nigel-Ecma May 31, 2021
d264cee
Updated to now include:
Nigel-Ecma May 31, 2021
c238d13
fix adjacent key typo
Nigel-Ecma May 31, 2021
d147b8b
Missed out lexical-structure.md
Nigel-Ecma May 31, 2021
08607f9
Update standard/expressions.md
Nigel-Ecma Jun 25, 2021
854f9d6
Update standard/expressions.md
Nigel-Ecma Jun 25, 2021
5ed92c2
- A number of small changes resolving issues raised in the comments.
Nigel-Ecma Jun 25, 2021
e4affe1
Fix some bad links
Nigel-Ecma Jun 25, 2021
181462d
And yet more link fixes...
Nigel-Ecma Jun 25, 2021
4d995f7
And I continue to whittle 'em down...
Nigel-Ecma Jun 25, 2021
1918dae
Addressed some issues raised and made a few corrections/improvements …
Nigel-Ecma Sep 14, 2021
78f7fba
Merge in changes to draft-v6 since all-null-conditional-ops branched off
Nigel-Ecma Sep 21, 2021
10c969b
Rename captured_access to dependent_access
Nigel-Ecma Sep 26, 2021
59226a8
Merge branch 'draft-v6' into alt-null-conditional-ops to bring in lat…
Nigel-Ecma Sep 27, 2021
04a3841
Merge in changes from draft-v6 and keep grammar.md up-to-date
Nigel-Ecma Sep 27, 2021
e1133a3
Apply suggestions from code review
Nigel-Ecma Oct 17, 2021
4457d3e
Fix editing snafu unearthed by Bill & Jon. Mea culpa.
Nigel-Ecma Oct 19, 2021
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13 changes: 9 additions & 4 deletions standard/expressions.md
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Expand Up @@ -1279,11 +1279,16 @@ In a member access of the form `E.I`, if `E` is a single identifier, and if the

### §null-conditional-member-access Null Conditional Member Access
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I've just been trying to figure out how this works in a couple of cases, and while I think it's the right approach, we may need a bit more explanation.

For example consider:

string x = null;
int? y = x?.GetHashCode();

My understanding is that that is a null_conditional_member_access with a dependent_access of () - so we get the null value. It's not a null_conditional_invocation_expression, because that's only used in places where the result (if any) is discarded. Is that the case? If so, it's a bit confusing because x.GetHashCode() is an invocation expresson, isn't it?

I'm not suggesting that we change any of the existing text - just consider adding an example/note.


A *null_conditional_member_access* consists of a *primary_expression* followed by a "`?.`" token, followed by an *Identifier*, optionally followed by a *type_argument_list*.
A *null_conditional_member_access* consists of a *primary_expression* followed by a "`?.`" token, followed by an *Identifier* with an optional *type_argument_list*, followed by zero or more *unconditional_access_part*s.
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```ANTLR
null_conditional_member_access
: primary_expression '?.' Identifier type_argument_list?
: primary_expression '?.' Identifier type_argument_list? unconditional_access_part*
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;

unconditional_access_part
: '.' Identifier type_argument_list?
| '[' argument_list ']'
;
```

Expand Down Expand Up @@ -1547,11 +1552,11 @@ Depending on the context in which it is used, an indexer access causes invocatio

### §null-conditional-element-access Null Conditional Element Access

A *null_conditional_element_access* consists of a *primary_no_array_creation_expression* followed by a "`?[`" token, followed by an *argument_list*, followed by a "`]`" token.
A *null_conditional_element_access* consists of a *primary_no_array_creation_expression* followed by a "`?[`" token, followed by an *argument_list*, followed by a "`]`" token, followed by zero or more *unconditional_access_part*s.
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```ANTLR
null_conditional_element_access
: primary_no_array_creation_expression '?[' argument_list ']'
: primary_no_array_creation_expression '?[' argument_list ']' unconditional_access_part*
;
```

Expand Down