rfc:union_types
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rfc:union_types [2016/06/14 14:40] levim s/T/t/ |
rfc:union_types [2017/09/22 13:28] (current) |
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| * Date: 2015-02-14 | * Date: 2015-02-14 | ||
| * Author: Levi Morrison < | * Author: Levi Morrison < | ||
| - | * Status: | + | * Status: |
| * First Published at: http:// | * First Published at: http:// | ||
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| * They allow the PHP engine to enforce the correct type of variable passed to or returned from a function. | * They allow the PHP engine to enforce the correct type of variable passed to or returned from a function. | ||
| - | * They make it easier to reason about what types need to be passed to or can be returned from a function. | + | * They make it easier to reason about what types need to be passed to or can be returned from a function. |
| For a lot of functions in PHP each parameter will only be one type. Similarly, for the majority of functions the return value will only ever be of one type. | For a lot of functions in PHP each parameter will only be one type. Similarly, for the majority of functions the return value will only ever be of one type. | ||
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| This RFC seeks to address these limitations. | This RFC seeks to address these limitations. | ||
| - | ==== Proposal ==== | + | ===== Proposal |
| This RFC proposes the ability to define multiple possible types for parameter and return types. To define a 'union type' a single vertical bar (OR) is placed between types e.g. '' | This RFC proposes the ability to define multiple possible types for parameter and return types. To define a 'union type' a single vertical bar (OR) is placed between types e.g. '' | ||
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| There can be more than two types in the union. | There can be more than two types in the union. | ||
| - | === Parameter type examples === | + | ==== Parameter type examples |
| A function that requires either a string or an array is passed to it as the parameter: | A function that requires either a string or an array is passed to it as the parameter: | ||
| <PHP> | <PHP> | ||
| Line 59: | Line 59: | ||
| For this example, it is clear to both static analysis tools and humans that passing anything other than a ParameterGenerator object or a string to this function, would be an error. | For this example, it is clear to both static analysis tools and humans that passing anything other than a ParameterGenerator object or a string to this function, would be an error. | ||
| - | === Return type example === | + | ==== Return type example |
| A userland definition of '' | A userland definition of '' | ||
| Line 166: | Line 166: | ||
| This RFC requires that two-thirds of voters vote in favor of the RFC to pass. | This RFC requires that two-thirds of voters vote in favor of the RFC to pass. | ||
| - | <doodle title=" | + | <doodle title=" |
| * Yes | * Yes | ||
| * No | * No | ||
| Line 173: | Line 173: | ||
| Additionally, | Additionally, | ||
| - | <doodle title=" | + | <doodle title=" |
| * Yes | * Yes | ||
| * No | * No | ||
| </ | </ | ||
| | | ||
| - | <doodle title=" | + | <doodle title=" |
| * Yes | * Yes | ||
| * No | * No | ||
rfc/union_types.1465915211.txt.gz · Last modified: 2017/09/22 13:28 (external edit)