rfc:object_keys_in_arrays
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rfc:object_keys_in_arrays [2021/01/07 16:36] – created nikic | rfc:object_keys_in_arrays [2021/01/11 14:22] (current) – nikic | ||
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* Status: Draft | * Status: Draft | ||
* Target Version: PHP 8.1 | * Target Version: PHP 8.1 | ||
- | * Implementation: | + | * Implementation: |
===== Introduction ===== | ===== Introduction ===== | ||
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The enumerations RFC suggests to instead use either '' | The enumerations RFC suggests to instead use either '' | ||
- | This RFC proposes to address this issue by allowing the use of object keys (and thus enum keys) inside array. | + | This RFC proposes to address this issue by allowing the use of object keys (and thus enum keys) inside array. This change will also make it simpler to support other key kinds in the future, for example if PHP were to switch to arbitrary-precision integers. |
===== Proposal ===== | ===== Proposal ===== | ||
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Object keys are compared by object identity. That is, '' | Object keys are compared by object identity. That is, '' | ||
- | While an extension to support custom object hashing and comparison overloads may be possible in the future, it is very much out of scope of this proposal. | + | While an extension to support custom object hashing and comparison overloads may be possible in the future, it is very much out of scope of this proposal. '' |
+ | |||
+ | ==== Impact on standard library functions ==== | ||
+ | |||
+ | For most standard library functions the behavior of object keys is straightforward. E.g. '' | ||
+ | |||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * ... | ||
===== Backward Incompatible Changes ===== | ===== Backward Incompatible Changes ===== | ||
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</ | </ | ||
- | It should be noted that Traversables could already yield non-string, non-integer keys beforehand and as such more generic code already needs to handle them gracefully. | + | It should be noted that Traversables could already yield non-string, non-integer keys beforehand and as such more generic code already needs to handle them gracefully. |
===== Implementation Impact ===== | ===== Implementation Impact ===== | ||
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The size of this structure remains the same on 64-bit systems (on legacy 32-bit systems it is 8 bytes larger). | The size of this structure remains the same on 64-bit systems (on legacy 32-bit systems it is 8 bytes larger). | ||
- | The stored hash value is reduced to 32-bits in order to fit into u2 space. As hash indexes | + | The stored hash value is reduced to 32-bits in order to fit into u2 space. As hash indices |
- | The key zval may have type '' | + | The key zval may have type '' |
- | In order to support | + | A number of new hash APIs for working with object keys is added: |
- | A non-exhaustive list of new functions: | + | <code c> |
+ | ZEND_API zval* ZEND_FASTCALL zend_hash_obj_key_add(HashTable *ht, zend_object *obj_key, zval *val); | ||
+ | ZEND_API zval* ZEND_FASTCALL zend_hash_obj_key_add_new(HashTable *ht, zend_object *obj_key, zval *val); | ||
+ | ZEND_API zval* ZEND_FASTCALL zend_hash_obj_key_update(HashTable *ht, zend_object *obj_key, zval *val); | ||
+ | ZEND_API zend_result ZEND_FASTCALL zend_hash_obj_key_del(HashTable *ht, zend_object *obj_key); | ||
+ | ZEND_API zval* ZEND_FASTCALL zend_hash_obj_key_find(const HashTable *ht, zend_object *obj_key); | ||
+ | </ | ||
+ | |||
+ | However, the majority | ||
+ | |||
+ | Instead, a new '' | ||
+ | |||
+ | The following | ||
<code c> | <code c> | ||
- | // This omits various _ind, _ptr, etc variants. | ||
ZEND_API zval* ZEND_FASTCALL zend_hash_zkey_add_or_update(HashTable *ht, zval *key, zval *val, uint32_t flag); | ZEND_API zval* ZEND_FASTCALL zend_hash_zkey_add_or_update(HashTable *ht, zval *key, zval *val, uint32_t flag); | ||
ZEND_API zval* ZEND_FASTCALL zend_hash_zkey_update(HashTable *ht, zval *key, zval *val); | ZEND_API zval* ZEND_FASTCALL zend_hash_zkey_update(HashTable *ht, zval *key, zval *val); | ||
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ZEND_API zval* ZEND_FASTCALL zend_hash_zkey_find(const HashTable *ht, zval *key); | ZEND_API zval* ZEND_FASTCALL zend_hash_zkey_find(const HashTable *ht, zval *key); | ||
static zend_always_inline zend_bool zend_hash_zkey_exists(const HashTable *ht, zval *key); | static zend_always_inline zend_bool zend_hash_zkey_exists(const HashTable *ht, zval *key); | ||
+ | |||
+ | // This is a low-level API that requires the hash value in u2 to be initialized. | ||
+ | static zend_always_inline zval *_zend_hash_zkey_append(HashTable *ht, zval *key, zval *zv); | ||
</ | </ | ||
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</ | </ | ||
- | The existing '' | + | The existing '' |
The '' | The '' | ||
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The new macros can be polyfilled for older PHP versions, which is also why this introduces new macros rather than modifying existing ones. | The new macros can be polyfilled for older PHP versions, which is also why this introduces new macros rather than modifying existing ones. | ||
+ | |||
+ | The '' | ||
+ | |||
+ | <code c> | ||
+ | /* This function populates `key` with a copy of the key, or a null zval if exhausted. */ | ||
+ | ZEND_API void ZEND_FASTCALL zend_hash_get_current_key_zval_ex(const HashTable *ht, zval *key, HashPosition *pos); | ||
+ | |||
+ | /* This function returns the key zval directly, or NULL if exhausted. */ | ||
+ | ZEND_API zval* ZEND_FASTCALL zend_hash_get_current_zkey(const HashTable *ht, HashPosition *pos); | ||
+ | </ | ||
+ | |||
+ | The '' | ||
===== Vote ===== | ===== Vote ===== |
rfc/object_keys_in_arrays.1610037416.txt.gz · Last modified: 2021/01/07 16:36 by nikic