38 lines
1.7 KiB
Markdown
38 lines
1.7 KiB
Markdown
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# Attributes on local functions
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## Attributes
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Local function declarations are now permitted to have [attributes](../spec/attributes.md). Parameters and type parameters on local functions are also allowed to have attributes.
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Attributes with a specified meaning when applied to a method, its parameters, or its type parameters will have the same meaning when applied to a local function, its parameters, or its type parameters, respectively.
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A local function can be made conditional in the same sense as a [conditional method](../spec/attributes.md#the-conditional-attribute) by decorating it with a `[ConditionalAttribute]`. A conditional local function must also be `static`. All restrictions on conditional methods also apply to conditional local functions, including that the return type must be `void`.
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## Extern
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The `extern` modifier is now permitted on local functions. This makes the local function external in the same sense as an [external method](../spec/classes.md#external-methods).
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Similarly to an external method, the *local-function-body* of an external local function must be a semicolon. A semicolon *local-function-body* is only permitted on an external local function.
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An external local function must also be `static`.
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## Syntax
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The [local functions grammar](csharp-7.0/local-functions.md#syntax-grammar) is modified as follows:
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```
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local-function-header
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: attributes? local-function-modifiers? return-type identifier type-parameter-list?
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( formal-parameter-list? ) type-parameter-constraints-clauses
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;
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local-function-modifiers
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: (async | unsafe | static | extern)*
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;
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local-function-body
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: block
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| arrow-expression-body
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| ';'
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;
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```
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