> For the complete documentation index, see [llms.txt](https://swift.unicorndonkeys.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swift.unicorndonkeys.com/riferimento-del-linguaggio/riepilogo-della-grammatica.md). # Riepilogo della grammatica (Summary of the Grammar) Leggi l'intera grammatica formale. ## [Struttura lessicale](/riferimento-del-linguaggio/struttura-lessicale.md) {% hint style="info" %} **Grammatica degli spazi bianchi:** *whitespace* → *whitespace-item* *whitespace?*\ *whitespace-item* → *line-break*\ *whitespace-item* → *inline-space*\ *whitespace-item* → *comment*\ *whitespace-item* → *multiline-comment*\ *whitespace-item* → U+0000, U+000B, or U+000C *line-break* → U+000A\ *line-break* → U+000D\ *line-break* → U+000D followed by U+000A *inline-spaces* → *inline-space* *inline-spaces?*\ *inline-space* → U+0009 or U+0020 *comment* → **`//`** *comment-text* *line-break*\ *multiline-comment* → **`/*`** *multiline-comment-text* **`*/`** *comment-text* → *comment-text-item* *comment-text?*\ *comment-text-item* → Any Unicode scalar value except U+000A or U+000D *multiline-comment-text* → *multiline-comment-text-item* *multiline-comment-text?*\ *multiline-comment-text-item* → *multiline-comment*\ *multiline-comment-text-item* → *comment-text-item*\ *multiline-comment-text-item* → Any Unicode scalar value except **`/*`** or **`*/`** {% endhint %} {% hint style="info" %} **Grammatica di un identificatore:** *identifier* → *identifier-head* *identifier-characters?*\ *identifier* → *raw-identifier*\ *identifier* → *implicit-parameter-name*\ *identifier* → *property-wrapper-projection*\ *identifier-list* → *identifier* | *identifier* **`,`** *identifier-list* *identifier-head* → Upper- or lowercase letter A through Z\ *identifier-head* → **`_`**\ *identifier-head* → U+00A8, U+00AA, U+00AD, U+00AF, U+00B2–U+00B5, or U+00B7–U+00BA\ *identifier-head* → U+00BC–U+00BE, U+00C0–U+00D6, U+00D8–U+00F6, or U+00F8–U+00FF\ *identifier-head* → U+0100–U+02FF, U+0370–U+167F, U+1681–U+180D, or U+180F–U+1DBF\ *identifier-head* → U+1E00–U+1FFF\ *identifier-head* → U+200B–U+200D, U+202A–U+202E, U+203F–U+2040, U+2054, or U+2060–U+206F\ *identifier-head* → U+2070–U+20CF, U+2100–U+218F, U+2460–U+24FF, or U+2776–U+2793\ *identifier-head* → U+2C00–U+2DFF or U+2E80–U+2FFF\ *identifier-head* → U+3004–U+3007, U+3021–U+302F, U+3031–U+303F, or U+3040–U+D7FF\ *identifier-head* → U+F900–U+FD3D, U+FD40–U+FDCF, U+FDF0–U+FE1F, or U+FE30–U+FE44\ *identifier-head* → U+FE47–U+FFFD\ *identifier-head* → U+10000–U+1FFFD, U+20000–U+2FFFD, U+30000–U+3FFFD, or U+40000–U+4FFFD\ *identifier-head* → U+50000–U+5FFFD, U+60000–U+6FFFD, U+70000–U+7FFFD, or U+80000–U+8FFFD\ *identifier-head* → U+90000–U+9FFFD, U+A0000–U+AFFFD, U+B0000–U+BFFFD, or U+C0000–U+CFFFD\ *identifier-head* → U+D0000–U+DFFFD or U+E0000–U+EFFFD *identifier-character* → *decimal-digit*\ *identifier-character* → U+0300–U+036F, U+1DC0–U+1DFF, U+20D0–U+20FF, or U+FE20–U+FE2F\ *identifier-character* → *identifier-head*\ *identifier-characters* → *identifier-character* *identifier-characters?* *implicit-parameter-name* → **`$`** *decimal-digits*\ *property-wrapper-projection* → **`$`** *identifier-characters* *raw-identifier* → **`` ` ``** *raw-identifier-characters* **`` ` ``**\ *raw-identifier-character* → Any Unicode scalar value except **`` ` ``**, **`\`**, U+0000, U+000A, or U+000D *raw-identifier-characters* → *raw-identifier-character* *raw-identifier-characters?* {% endhint %} {% hint style="info" %} **Grammatica di un letterale:** *literal* → *numeric-literal* | *string-literal* | *regular-expression-literal* | *boolean-literal* | *nil-literal* *numeric-literal* → *signed-integer-literal* | *signed-floating-point-literal*\ *boolean-literal* → **`true`** | **`false`**\ *nil-literal* → **`nil`** {% endhint %} {% hint style="info" %} **Grammatica di un letterale intero:** *signed-integer-literal* → **`-`***?* *integer-literal* *integer-literal* → *binary-literal*\ *integer-literal* → *octal-literal*\ *integer-literal* → *decimal-literal*\ *integer-literal* → *hexadecimal-literal* *binary-literal* → **`0b`** *binary-digit* *binary-literal-characters?*\ *binary-digit* → Digit 0 or 1\ *binary-literal-character* → *binary-digit* | **`_`**\ *binary-literal-characters* → *binary-literal-character* *binary-literal-characters?* *octal-literal* → **`0o`** *octal-digit* *octal-literal-characters?*\ *octal-digit* → Digit 0 through 7\ *octal-literal-character* → *octal-digit* | **`_`**\ *octal-literal-characters* → *octal-literal-character* *octal-literal-characters?* *decimal-literal* → *decimal-digit* *decimal-literal-characters?*\ *decimal-digit* → Digit 0 through 9\ *decimal-digits* → *decimal-digit* *decimal-digits?*\ *decimal-literal-character* → *decimal-digit* | **`_`**\ *decimal-literal-characters* → *decimal-literal-character* *decimal-literal-characters?* *hexadecimal-literal* → **`0x`** *hexadecimal-digit* *hexadecimal-literal-characters?*\ *hexadecimal-digit* → Digit 0 through 9, a through f, or A through F\ *hexadecimal-literal-character* → *hexadecimal-digit* | **`_`**\ *hexadecimal-literal-characters* → *hexadecimal-literal-character* *hexadecimal-literal-characters?* {% endhint %} {% hint style="info" %} **Grammatica di un letterale in virgola mobile:** *signed-floating-point-literal* → > **`-`***?* *floating-point-literal* *floating-point-literal* → *decimal-literal* *decimal-fraction?* *decimal-exponent?*\ *floating-point-literal* → *hexadecimal-literal* *hexadecimal-fraction?* *hexadecimal-exponent* *decimal-fraction* → **`.`** *decimal-literal*\ *decimal-exponent* → *floating-point-e* *sign?* *decimal-literal* *hexadecimal-fraction* → **`.`** *hexadecimal-digit* *hexadecimal-literal-characters?*\ *hexadecimal-exponent* → *floating-point-p* *sign?* *decimal-literal* *floating-point-e* → **`e`** | **`E`**\ *floating-point-p* → **`p`** | **`P`**\ *sign* → **`+`** | **`-`** {% endhint %} {% hint style="info" %} **Grammatica di un letterale stringa:** *string-literal* → *static-string-literal* | *interpolated-string-literal* *string-literal-opening-delimiter* → *extended-string-literal-delimiter?* **`"`**\ *string-literal-closing-delimiter* → **`"`** *extended-string-literal-delimiter?* *static-string-literal* → *string-literal-opening-delimiter* *quoted-text?* *string-literal-closing-delimiter*\ *static-string-literal* → *multiline-string-literal-opening-delimiter* *multiline-quoted-text?* *multiline-string-literal-closing-delimiter* *multiline-string-literal-opening-delimiter* → *extended-string-literal-delimiter?* **`"""`**\ *multiline-string-literal-closing-delimiter* → **`"""`** *extended-string-literal-delimiter?*\ *extended-string-literal-delimiter* → **`#`** *extended-string-literal-delimiter?* *quoted-text* → *quoted-text-item* *quoted-text?*\ *quoted-text-item* → *escaped-character*\ *quoted-text-item* → Any Unicode scalar value except **`"`**, **`\`**, U+000A, or U+000D *multiline-quoted-text* → *multiline-quoted-text-item* *multiline-quoted-text?*\ *multiline-quoted-text-item* → *escaped-character*\ *multiline-quoted-text-item* → Any Unicode scalar value except **`\`**\ *multiline-quoted-text-item* → *escaped-newline* *interpolated-string-literal* → *string-literal-opening-delimiter* *interpolated-text?* *string-literal-closing-delimiter*\ *interpolated-string-literal* → *multiline-string-literal-opening-delimiter* *multiline-interpolated-text?* *multiline-string-literal-closing-delimiter* *interpolated-text* → *interpolated-text-item* *interpolated-text?*\ *interpolated-text-item* → **`\(`** *expression* **`)`** | *quoted-text-item* *multiline-interpolated-text* → *multiline-interpolated-text-item* *multiline-interpolated-text?*\ *multiline-interpolated-text-item* → **`\(`** *expression* **`)`** | *multiline-quoted-text-item* *escape-sequence* → **`\`** *extended-string-literal-delimiter*\ *escaped-character* → *escape-sequence* **`0`** | *escape-sequence* **`\`** | *escape-sequence* **`t`** | *escape-sequence* **`n`** | *escape-sequence* **`r`** | *escape-sequence* **`"`** | *escape-sequence* **`'`**\ *escaped-character* → *escape-sequence* **`u`** **`{`** *unicode-scalar-digits* **`}`**\ *unicode-scalar-digits* → Between one and eight hexadecimal digits *escaped-newline* → *escape-sequence* *inline-spaces?* *line-break* {% endhint %} {% hint style="info" %} **Grammatica di un letterale espressione regolare:** *regular-expression-literal* → *regular-expression-literal-opening-delimiter* *regular-expression* *regular-expression-literal-closing-delimiter*\ *regular-expression* → Any regular expression *regular-expression-literal-opening-delimiter* → *extended-regular-expression-literal-delimiter?* **`/`**\ *regular-expression-literal-closing-delimiter* → **`/`** *extended-regular-expression-literal-delimiter?* *extended-regular-expression-literal-delimiter* → **`#`** *extended-regular-expression-literal-delimiter?* {% endhint %} {% hint style="info" %} **Grammatica degli operatori:** *operator* → *operator-head* *operator-characters?*\ *operator* → *dot-operator-head* *dot-operator-characters* *operator-head* → **`/`** | **`=`** | **`-`** | **`+`** | **`!`** | **`*`** | **`%`** | **`<`** | **`>`** | **`&`** | **`|`** | **`^`** | **`~`** | **`?`**\ *operator-head* → U+00A1–U+00A7\ *operator-head* → U+00A9 or U+00AB\ *operator-head* → U+00AC or U+00AE\ *operator-head* → U+00B0–U+00B1\ *operator-head* → U+00B6, U+00BB, U+00BF, U+00D7, or U+00F7\ *operator-head* → U+2016–U+2017\ *operator-head* → U+2020–U+2027\ *operator-head* → U+2030–U+203E\ *operator-head* → U+2041–U+2053\ *operator-head* → U+2055–U+205E\ *operator-head* → U+2190–U+23FF\ *operator-head* → U+2500–U+2775\ *operator-head* → U+2794–U+2BFF\ *operator-head* → U+2E00–U+2E7F\ *operator-head* → U+3001–U+3003\ *operator-head* → U+3008–U+3020\ *operator-head* → U+3030 *operator-character* → *operator-head*\ *operator-character* → U+0300–U+036F\ *operator-character* → U+1DC0–U+1DFF\ *operator-character* → U+20D0–U+20FF\ *operator-character* → U+FE00–U+FE0F\ *operator-character* → U+FE20–U+FE2F\ *operator-character* → U+E0100–U+E01EF\ *operator-characters* → *operator-character* *operator-characters?* *dot-operator-head* → **`.`**\ *dot-operator-character* → **`.`** | *operator-character*\ *dot-operator-characters* → *dot-operator-character* *dot-operator-characters?* *infix-operator* → *operator*\ *prefix-operator* → *operator*\ *postfix-operator* → *operator* {% endhint %} ## [Tipi](/riferimento-del-linguaggio/tipi.md) {% hint style="info" %} **Grammatica di un tipo:** *type* → *function-type*\ *type* → *array-type*\ *type* → *dictionary-type*\ *type* → *type-identifier*\ *type* → *tuple-type*\ *type* → *optional-type*\ *type* → *implicitly-unwrapped-optional-type*\ *type* → *protocol-composition-type*\ *type* → *opaque-type*\ *type* → *boxed-protocol-type*\ *type* → *metatype-type*\ *type* → *any-type*\ *type* → *self-type*\ *type* → **`(`** *type* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un'annotazione di tipo:** *type-annotation* → **`:`** *attributes?* *type* {% endhint %} {% hint style="info" %} **Grammatica di un identificatore di tipo:** *type-identifier* → *type-name* *generic-argument-clause?* | *type-name* *generic-argument-clause?* **`.`** *type-identifier*\ *type-name* → *identifier* {% endhint %} {% hint style="info" %} **Grammatica di un tipo tupla:** *tuple-type* → **`(`** **`)`** | **`(`** *tuple-type-element* **`,`** *tuple-type-element-list* **`)`**\ *tuple-type-element-list* → *tuple-type-element* | *tuple-type-element* **`,`** *tuple-type-element-list*\ *tuple-type-element* → *element-name* *type-annotation* | *type*\ *element-name* → *identifier* {% endhint %} {% hint style="info" %} **Grammatica di un tipo funzione:** *function-type* → *attributes?* *function-type-argument-clause* **`async`***?* *throws-clause?* **`->`** *type* *function-type-argument-clause* → **`(`** **`)`**\ *function-type-argument-clause* → **`(`** *function-type-argument-list* **`...`***?* **`)`** *function-type-argument-list* → *function-type-argument* | *function-type-argument* **`,`** *function-type-argument-list*\ *function-type-argument* → *attributes?* *parameter-modifier?* *type* | *argument-label* *type-annotation*\ *argument-label* → *identifier* *throws-clause* → **`throws`** | **`throws`** **`(`** *type* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo array:** *array-type* → **`[`** *type* **`]`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo dizionario:** *dictionary-type* → **`[`** *type* **`:`** *type* **`]`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo opzionale:** *optional-type* → *type* **`?`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo opzionale con unwrapping implicito:** *implicitly-unwrapped-optional-type* → *type* **`!`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo composizione di protocolli:** *protocol-composition-type* → *type-identifier* **`&`** *protocol-composition-continuation*\ *protocol-composition-continuation* → *type-identifier* | *protocol-composition-type* {% endhint %} {% hint style="info" %} **Grammatica di un tipo opaco:** *opaque-type* → **`some`** *type* {% endhint %} {% hint style="info" %} **Grammatica di un tipo protocollo boxed:** *boxed-protocol-type* → **`any`** *type* {% endhint %} {% hint style="info" %} **Grammatica di un tipo metatipo:** *metatype-type* → *type* **`.`** **`Type`** | *type* **`.`** **`Protocol`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo Any:** *any-type* → **`Any`** {% endhint %} {% hint style="info" %} **Grammatica di un tipo Self:** *self-type* → **`Self`** {% endhint %} {% hint style="info" %} **Grammatica di una clausola di ereditarietà del tipo:** *type-inheritance-clause* → **`:`** *type-inheritance-list*\ *type-inheritance-list* → *attributes?* **`~`***?* *type-identifier* | *attributes?* **`~`***?* *type-identifier* **`,`** *type-inheritance-list* {% endhint %} ## [Espressioni](/riferimento-del-linguaggio/espressioni.md) {% hint style="info" %} **Grammatica di un'espressione:** *expression* → *try-operator?* *await-operator?* *prefix-expression* *infix-expressions?* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione prefissa:** *prefix-expression* → *prefix-operator?* *postfix-expression*\ *prefix-expression* → *in-out-expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione in-out:** *in-out-expression* → **`&`** *primary-expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione try:** *try-operator* → **`try`** | **`try`** **`?`** | **`try`** **`!`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione await:** *await-operator* → **`await`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione infissa:** *infix-expression* → *infix-operator* *prefix-expression*\ *infix-expression* → *assignment-operator* *try-operator?* *await-operator?* *prefix-expression*\ *infix-expression* → *conditional-operator* *try-operator?* *await-operator?* *prefix-expression*\ *infix-expression* → *type-casting-operator*\ *infix-expressions* → *infix-expression* *infix-expressions?* {% endhint %} {% hint style="info" %} **Grammatica di un operatore di assegnazione:** *assignment-operator* → **`=`** {% endhint %} {% hint style="info" %} **Grammatica di un operatore condizionale:** *conditional-operator* → **`?`** *expression* **`:`** {% endhint %} {% hint style="info" %} **Grammatica di un operatore di type casting:** *type-casting-operator* → **`is`** *type*\ *type-casting-operator* → **`as`** *type*\ *type-casting-operator* → **`as`** **`?`** *type*\ *type-casting-operator* → **`as`** **`!`** *type* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione primaria:** *primary-expression* → *identifier* *generic-argument-clause?*\ *primary-expression* → *literal-expression*\ *primary-expression* → *self-expression*\ *primary-expression* → *superclass-expression*\ *primary-expression* → *conditional-expression*\ *primary-expression* → *closure-expression*\ *primary-expression* → *parenthesized-expression*\ *primary-expression* → *tuple-expression*\ *primary-expression* → *implicit-member-expression*\ *primary-expression* → *wildcard-expression*\ *primary-expression* → *macro-expansion-expression*\ *primary-expression* → *key-path-expression*\ *primary-expression* → *selector-expression*\ *primary-expression* → *key-path-string-expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione letterale:** *literal-expression* → *literal*\ *literal-expression* → *array-literal* | *dictionary-literal* | *playground-literal* *array-literal* → **`[`** *array-literal-items?* **`,`***?* **`]`**\ *array-literal-items* → *array-literal-item* | *array-literal-item* **`,`** *array-literal-items*\ *array-literal-item* → *expression* *dictionary-literal* → **`[`** *dictionary-literal-items* **`,`***?* **`]`** | **`[`** **`:`** **`]`**\ *dictionary-literal-items* → *dictionary-literal-item* | *dictionary-literal-item* **`,`** *dictionary-literal-items*\ *dictionary-literal-item* → *expression* **`:`** *expression* *playground-literal* → **`#colorLiteral`** **`(`** **`red`** **`:`** *expression* **`,`** **`green`** **`:`** *expression* **`,`** **`blue`** **`:`** *expression* **`,`** **`alpha`** **`:`** *expression* **`)`**\ *playground-literal* → **`#fileLiteral`** **`(`** **`resourceName`** **`:`** *expression* **`)`**\ *playground-literal* → **`#imageLiteral`** **`(`** **`resourceName`** **`:`** *expression* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione self:** *self-expression* → **`self`** | *self-method-expression* | *self-subscript-expression* | *self-initializer-expression* *self-method-expression* → **`self`** **`.`** *identifier*\ *self-subscript-expression* → **`self`** **`[`** *function-call-argument-list* **`]`**\ *self-initializer-expression* → **`self`** **`.`** **`init`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione superclass:** *superclass-expression* → *superclass-method-expression* | *superclass-subscript-expression* | *superclass-initializer-expression* *superclass-method-expression* → **`super`** **`.`** *identifier*\ *superclass-subscript-expression* → **`super`** **`[`** *function-call-argument-list* **`]`**\ *superclass-initializer-expression* → **`super`** **`.`** **`init`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione condizionale:** *conditional-expression* → *if-expression* | *switch-expression* *if-expression* → **`if`** *condition-list* **`{`** *statement* **`}`** *if-expression-tail*\ *if-expression-tail* → **`else`** *if-expression*\ *if-expression-tail* → **`else`** **`{`** *statement* **`}`** *switch-expression* → **`switch`** *expression* **`{`** *switch-expression-cases* **`}`**\ *switch-expression-cases* → *switch-expression-case* *switch-expression-cases?*\ *switch-expression-case* → *case-label* *statement*\ *switch-expression-case* → *default-label* *statement* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione closure:** *closure-expression* → **`{`** *attributes?* *closure-signature?* *statements?* **`}`** *closure-signature* → *capture-list?* *closure-parameter-clause* **`async`***?* *throws-clause?* *function-result?* **`in`**\ *closure-signature* → *capture-list* **`in`** *closure-parameter-clause* → **`(`** **`)`** | **`(`** *closure-parameter-list* **`,`***?* **`)`** | *identifier-list*\ *closure-parameter-list* → *closure-parameter* | *closure-parameter* **`,`** *closure-parameter-list*\ *closure-parameter* → *closure-parameter-name* *type-annotation?*\ *closure-parameter* → *closure-parameter-name* *type-annotation* **`...`**\ *closure-parameter-name* → *identifier* *capture-list* → **`[`** *capture-list-items* **`,`***?* **`]`**\ *capture-list-items* → *capture-list-item* | *capture-list-item* **`,`** *capture-list-items*\ *capture-list-item* → *capture-specifier?* *identifier*\ *capture-list-item* → *capture-specifier?* *identifier* **`=`** *expression*\ *capture-list-item* → *capture-specifier?* *self-expression*\ *capture-specifier* → **`weak`** | **`unowned`** | **`unowned(safe)`** | **`unowned(unsafe)`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione membro implicita:** *implicit-member-expression* → **`.`** *identifier*\ *implicit-member-expression* → **`.`** *identifier* **`.`** *postfix-expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione tra parentesi:** *parenthesized-expression* → **`(`** *expression* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione tupla:** *tuple-expression* → **`(`** **`)`** | **`(`** *tuple-element* **`,`** *tuple-element-list* **`,`***?* **`)`**\ *tuple-element-list* → *tuple-element* | *tuple-element* **`,`** *tuple-element-list*\ *tuple-element* → *expression* | *identifier* **`:`** *expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione wildcard:** *wildcard-expression* → **`_`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione di espansione di macro:** *macro-expansion-expression* → **`#`** *identifier* *generic-argument-clause?* *function-call-argument-clause?* *trailing-closures?* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione key-path:** *key-path-expression* → **`\`** *type?* **`.`** *key-path-components*\ *key-path-components* → *key-path-component* | *key-path-component* **`.`** *key-path-components*\ *key-path-component* → *identifier* *key-path-postfixes?* | *key-path-postfixes* *key-path-postfixes* → *key-path-postfix* *key-path-postfixes?*\ *key-path-postfix* → **`?`** | **`!`** | **`self`** | **`[`** *function-call-argument-list* **`]`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione selector:** *selector-expression* → **`#selector`** **`(`** *expression* **`)`**\ *selector-expression* → **`#selector`** **`(`** **`getter:`** *expression* **`)`**\ *selector-expression* → **`#selector`** **`(`** **`setter:`** *expression* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione stringa key-path:** *key-path-string-expression* → **`#keyPath`** **`(`** *expression* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione postfissa:** *postfix-expression* → *primary-expression*\ *postfix-expression* → *postfix-expression* *postfix-operator*\ *postfix-expression* → *function-call-expression*\ *postfix-expression* → *initializer-expression*\ *postfix-expression* → *explicit-member-expression*\ *postfix-expression* → *postfix-self-expression*\ *postfix-expression* → *subscript-expression*\ *postfix-expression* → *forced-value-expression*\ *postfix-expression* → *optional-chaining-expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione di chiamata di funzione:** *function-call-expression* → *postfix-expression* *function-call-argument-clause*\ *function-call-expression* → *postfix-expression* *function-call-argument-clause?* *trailing-closures* *function-call-argument-clause* → **`(`** **`)`** | **`(`** *function-call-argument-list* **`,`***?* **`)`**\ *function-call-argument-list* → *function-call-argument* | *function-call-argument* **`,`** *function-call-argument-list*\ *function-call-argument* → *expression* | *identifier* **`:`** *expression*\ *function-call-argument* → *operator* | *identifier* **`:`** *operator* *trailing-closures* → *closure-expression* *labeled-trailing-closures?*\ *labeled-trailing-closures* → *labeled-trailing-closure* *labeled-trailing-closures?*\ *labeled-trailing-closure* → *identifier* **`:`** *closure-expression* {% endhint %} {% hint style="info" %} **Grammatica di un'espressione di inizializzazione:** *initializer-expression* → *postfix-expression* **`.`** **`init`**\ *initializer-expression* → *postfix-expression* **`.`** **`init`** **`(`** *argument-names* **`)`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione membro esplicita:** *explicit-member-expression* → *postfix-expression* **`.`** *decimal-digits*\ *explicit-member-expression* → *postfix-expression* **`.`** *identifier* *generic-argument-clause?*\ *explicit-member-expression* → *postfix-expression* **`.`** *identifier* **`(`** *argument-names* **`)`**\ *explicit-member-expression* → *postfix-expression* *conditional-compilation-block* *argument-names* → *argument-name* *argument-names?*\ *argument-name* → *identifier* **`:`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione self postfissa:** *postfix-self-expression* → *postfix-expression* **`.`** **`self`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione subscript:** *subscript-expression* → *postfix-expression* **`[`** *function-call-argument-list* **`]`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione a valore forzato:** *forced-value-expression* → *postfix-expression* **`!`** {% endhint %} {% hint style="info" %} **Grammatica di un'espressione di optional chaining:** *optional-chaining-expression* → *postfix-expression* **`?`** {% endhint %} ## [Istruzioni](/riferimento-del-linguaggio/istruzioni.md) {% hint style="info" %} **Grammatica di un'istruzione:** *statement* → *expression* **`;`***?*\ *statement* → *declaration* **`;`***?*\ *statement* → *loop-statement* **`;`***?*\ *statement* → *branch-statement* **`;`***?*\ *statement* → *labeled-statement* **`;`***?*\ *statement* → *control-transfer-statement* **`;`***?*\ *statement* → *defer-statement* **`;`***?*\ *statement* → *do-statement* **`;`***?*\ *statement* → *compiler-control-statement*\ *statements* → *statement* *statements?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione di ciclo:** *loop-statement* → *for-in-statement*\ *loop-statement* → *while-statement*\ *loop-statement* → *repeat-while-statement* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione for-in:** *for-in-statement* → **`for`** **`case`***?* *pattern* **`in`** *expression* *where-clause?* *code-block* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione while:** *while-statement* → **`while`** *condition-list* *code-block* *condition-list* → *condition* | *condition* **`,`** *condition-list*\ *condition* → *expression* | *availability-condition* | *case-condition* | *optional-binding-condition* *case-condition* → **`case`** *pattern* *initializer*\ *optional-binding-condition* → **`let`** *pattern* *initializer?* | **`var`** *pattern* *initializer?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione repeat-while:** *repeat-while-statement* → **`repeat`** *code-block* **`while`** *expression* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione di diramazione:** *branch-statement* → *if-statement*\ *branch-statement* → *guard-statement*\ *branch-statement* → *switch-statement* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione if:** *if-statement* → **`if`** *condition-list* *code-block* *else-clause?*\ *else-clause* → **`else`** *code-block* | **`else`** *if-statement* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione guard:** *guard-statement* → **`guard`** *condition-list* **`else`** *code-block* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione switch:** *switch-statement* → **`switch`** *expression* **`{`** *switch-cases?* **`}`**\ *switch-cases* → *switch-case* *switch-cases?*\ *switch-case* → *case-label* *statements*\ *switch-case* → *default-label* *statements*\ *switch-case* → *conditional-switch-case* *case-label* → *attributes?* **`case`** *case-item-list* **`:`**\ *case-item-list* → *pattern* *where-clause?* | *pattern* *where-clause?* **`,`** *case-item-list*\ *default-label* → *attributes?* **`default`** **`:`** *where-clause* → **`where`** *where-expression*\ *where-expression* → *expression* *conditional-switch-case* → *switch-if-directive-clause* *switch-elseif-directive-clauses?* *switch-else-directive-clause?* *endif-directive*\ *switch-if-directive-clause* → *if-directive* *compilation-condition* *switch-cases?*\ *switch-elseif-directive-clauses* → *elseif-directive-clause* *switch-elseif-directive-clauses?*\ *switch-elseif-directive-clause* → *elseif-directive* *compilation-condition* *switch-cases?*\ *switch-else-directive-clause* → *else-directive* *switch-cases?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione etichettata:** *labeled-statement* → *statement-label* *loop-statement*\ *labeled-statement* → *statement-label* *if-statement*\ *labeled-statement* → *statement-label* *switch-statement*\ *labeled-statement* → *statement-label* *do-statement* *statement-label* → *label-name* **`:`**\ *label-name* → *identifier* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione di trasferimento del controllo:** *control-transfer-statement* → *break-statement*\ *control-transfer-statement* → *continue-statement*\ *control-transfer-statement* → *fallthrough-statement*\ *control-transfer-statement* → *return-statement*\ *control-transfer-statement* → *throw-statement* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione break:** *break-statement* → **`break`** *label-name?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione continue:** *continue-statement* → **`continue`** *label-name?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione fallthrough:** *fallthrough-statement* → **`fallthrough`** {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione return:** *return-statement* → **`return`** *expression?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione throw:** *throw-statement* → **`throw`** *expression* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione defer:** *defer-statement* → **`defer`** *code-block* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione do:** *do-statement* → **`do`** *throws-clause?* *code-block* *catch-clauses?*\ *catch-clauses* → *catch-clause* *catch-clauses?*\ *catch-clause* → **`catch`** *catch-pattern-list?* *code-block*\ *catch-pattern-list* → *catch-pattern* | *catch-pattern* **`,`** *catch-pattern-list*\ *catch-pattern* → *pattern* *where-clause?* {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione di controllo del compilatore:** *compiler-control-statement* → *conditional-compilation-block*\ *compiler-control-statement* → *line-control-statement*\ *compiler-control-statement* → *diagnostic-statement* {% endhint %} {% hint style="info" %} **Grammatica di un blocco di compilazione condizionale:** *conditional-compilation-block* → *if-directive-clause* *elseif-directive-clauses?* *else-directive-clause?* *endif-directive* *if-directive-clause* → *if-directive* *compilation-condition* *statements?*\ *elseif-directive-clauses* → *elseif-directive-clause* *elseif-directive-clauses?*\ *elseif-directive-clause* → *elseif-directive* *compilation-condition* *statements?*\ *else-directive-clause* → *else-directive* *statements?*\ *if-directive* → **`#if`**\ *elseif-directive* → **`#elseif`**\ *else-directive* → **`#else`**\ *endif-directive* → **`#endif`** *compilation-condition* → *platform-condition*\ *compilation-condition* → *identifier*\ *compilation-condition* → *boolean-literal*\ *compilation-condition* → **`(`** *compilation-condition* **`)`**\ *compilation-condition* → **`!`** *compilation-condition*\ *compilation-condition* → *compilation-condition* **`&&`** *compilation-condition*\ *compilation-condition* → *compilation-condition* **`||`** *compilation-condition* *platform-condition* → **`os`** **`(`** *operating-system* **`)`**\ *platform-condition* → **`arch`** **`(`** *architecture* **`)`**\ *platform-condition* → **`swift`** **`(`** **`>=`** *swift-version* **`)`** | **`swift`** **`(`** **`<`** *swift-version* **`)`**\ *platform-condition* → **`compiler`** **`(`** **`>=`** *swift-version* **`)`** | **`compiler`** **`(`** **`<`** *swift-version* **`)`**\ *platform-condition* → **`canImport`** **`(`** *import-path* **`)`**\ *platform-condition* → **`targetEnvironment`** **`(`** *environment* **`)`** *operating-system* → **`macOS`** | **`iOS`** | **`watchOS`** | **`tvOS`** | **`visionOS`** | **`Linux`** | **`Windows`**\ *architecture* → **`arm`** | **`arm64`** | **`i386`** | **`wasm32`** | **`x86_64`**\ *swift-version* → *decimal-digits* *swift-version-continuation?*\ *swift-version-continuation* → **`.`** *decimal-digits* *swift-version-continuation?*\ *environment* → **`simulator`** | **`macCatalyst`** {% endhint %} {% hint style="info" %} **Grammatica di un'istruzione di controllo della riga:** *line-control-statement* → **`#sourceLocation`** **`(`** **`file:`** *file-path* **`,`** **`line:`** *line-number* **`)`**\ *line-control-statement* → **`#sourceLocation`** **`(`** **`)`**\ *line-number* → A decimal integer greater than zero\ *file-path* → *static-string-literal* {% endhint %} {% hint style="info" %} **Grammatica di una condizione di disponibilità:** *availability-condition* → **`#available`** **`(`** *availability-arguments* **`)`**\ *availability-condition* → **`#unavailable`** **`(`** *availability-arguments* **`)`**\ *availability-arguments* → *availability-argument* | *availability-argument* **`,`** *availability-arguments*\ *availability-argument* → *platform-name* *platform-version*\ *availability-argument* → **`*`** *platform-name* → **`iOS`** | **`iOSApplicationExtension`**\ *platform-name* → **`macOS`** | **`macOSApplicationExtension`**\ *platform-name* → **`macCatalyst`** | **`macCatalystApplicationExtension`**\ *platform-name* → **`watchOS`** | **`watchOSApplicationExtension`**\ *platform-name* → **`tvOS`** | **`tvOSApplicationExtension`**\ *platform-name* → **`visionOS`** | **`visionOSApplicationExtension`**\ *platform-version* → *decimal-digits*\ *platform-version* → *decimal-digits* **`.`** *decimal-digits*\ *platform-version* → *decimal-digits* **`.`** *decimal-digits* **`.`** *decimal-digits* {% endhint %} ## [Dichiarazioni](/riferimento-del-linguaggio/dichiarazioni.md) {% hint style="info" %} **Grammatica di una dichiarazione:** *declaration* → *import-declaration*\ *declaration* → *constant-declaration*\ *declaration* → *variable-declaration*\ *declaration* → *typealias-declaration*\ *declaration* → *function-declaration*\ *declaration* → *enum-declaration*\ *declaration* → *struct-declaration*\ *declaration* → *class-declaration*\ *declaration* → *actor-declaration*\ *declaration* → *protocol-declaration*\ *declaration* → *initializer-declaration*\ *declaration* → *deinitializer-declaration*\ *declaration* → *extension-declaration*\ *declaration* → *subscript-declaration*\ *declaration* → *macro-declaration*\ *declaration* → *operator-declaration*\ *declaration* → *precedence-group-declaration* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di primo livello:** *top-level-declaration* → *statements?* {% endhint %} {% hint style="info" %} **Grammatica di un blocco di codice:** *code-block* → **`{`** *statements?* **`}`** {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di importazione:** *import-declaration* → *attributes?* **`import`** *import-kind?* *import-path* *import-kind* → **`typealias`** | **`struct`** | **`class`** | **`enum`** | **`protocol`** | **`let`** | **`var`** | **`func`**\ *import-path* → *identifier* | *identifier* **`.`** *import-path* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di costante:** *constant-declaration* → *attributes?* *declaration-modifiers?* **`let`** *pattern-initializer-list* *pattern-initializer-list* → *pattern-initializer* | *pattern-initializer* **`,`** *pattern-initializer-list*\ *pattern-initializer* → *pattern* *initializer?*\ *initializer* → **`=`** *expression* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di variabile:** *variable-declaration* → *variable-declaration-head* *pattern-initializer-list*\ *variable-declaration* → *variable-declaration-head* *variable-name* *type-annotation* *code-block*\ *variable-declaration* → *variable-declaration-head* *variable-name* *type-annotation* *getter-setter-block*\ *variable-declaration* → *variable-declaration-head* *variable-name* *type-annotation* *getter-setter-keyword-block*\ *variable-declaration* → *variable-declaration-head* *variable-name* *initializer* *willSet-didSet-block*\ *variable-declaration* → *variable-declaration-head* *variable-name* *type-annotation* *initializer?* *willSet-didSet-block* *variable-declaration-head* → *attributes?* *declaration-modifiers?* **`var`**\ *variable-name* → *identifier* *getter-setter-block* → *code-block*\ *getter-setter-block* → **`{`** *getter-clause* *setter-clause?* **`}`**\ *getter-setter-block* → **`{`** *setter-clause* *getter-clause* **`}`**\ *getter-clause* → *attributes?* *mutation-modifier?* **`get`** *code-block*\ *setter-clause* → *attributes?* *mutation-modifier?* **`set`** *setter-name?* *code-block*\ *setter-name* → **`(`** *identifier* **`)`** *getter-setter-keyword-block* → **`{`** *getter-keyword-clause* *setter-keyword-clause?* **`}`**\ *getter-setter-keyword-block* → **`{`** *setter-keyword-clause* *getter-keyword-clause* **`}`**\ *getter-keyword-clause* → *attributes?* *mutation-modifier?* **`get`**\ *setter-keyword-clause* → *attributes?* *mutation-modifier?* **`set`** *willSet-didSet-block* → **`{`** *willSet-clause* *didSet-clause?* **`}`**\ *willSet-didSet-block* → **`{`** *didSet-clause* *willSet-clause?* **`}`**\ *willSet-clause* → *attributes?* **`willSet`** *setter-name?* *code-block*\ *didSet-clause* → *attributes?* **`didSet`** *setter-name?* *code-block* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di alias di tipo:** *typealias-declaration* → *attributes?* *access-level-modifier?* **`typealias`** *typealias-name* *generic-parameter-clause?* *typealias-assignment*\ *typealias-name* → *identifier*\ *typealias-assignment* → **`=`** *type* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di funzione:** *function-declaration* → *function-head* *function-name* *generic-parameter-clause?* *function-signature* *generic-where-clause?* *function-body?* *function-head* → *attributes?* *declaration-modifiers?* **`func`**\ *function-name* → *identifier* | *operator* *function-signature* → *parameter-clause* **`async`***?* *throws-clause?* *function-result?*\ *function-signature* → *parameter-clause* **`async`***?* **`rethrows`** *function-result?*\ *function-result* → **`->`** *attributes?* *type*\ *function-body* → *code-block* *parameter-clause* → **`(`** **`)`** | **`(`** *parameter-list* **`,`***?* **`)`**\ *parameter-list* → *parameter* | *parameter* **`,`** *parameter-list*\ *parameter* → *external-parameter-name?* *local-parameter-name* *parameter-type-annotation* *default-argument-clause?*\ *parameter* → *external-parameter-name?* *local-parameter-name* *parameter-type-annotation*\ *parameter* → *external-parameter-name?* *local-parameter-name* *parameter-type-annotation* **`...`** *external-parameter-name* → *identifier*\ *local-parameter-name* → *identifier*\ *parameter-type-annotation* → **`:`** *attributes?* *parameter-modifier?* *type*\ *parameter-modifier* → **`inout`** | **`borrowing`** | **`consuming`** *default-argument-clause* → **`=`** *expression* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di enumerazione:** *enum-declaration* → *attributes?* *access-level-modifier?* *union-style-enum*\ *enum-declaration* → *attributes?* *access-level-modifier?* *raw-value-style-enum* *union-style-enum* → **`indirect`***?* **`enum`** *enum-name* *generic-parameter-clause?* *type-inheritance-clause?* *generic-where-clause?* **`{`** *union-style-enum-members?* **`}`**\ *union-style-enum-members* → *union-style-enum-member* *union-style-enum-members?*\ *union-style-enum-member* → *declaration* | *union-style-enum-case-clause* | *compiler-control-statement*\ *union-style-enum-case-clause* → *attributes?* **`indirect`***?* **`case`** *union-style-enum-case-list*\ *union-style-enum-case-list* → *union-style-enum-case* | *union-style-enum-case* **`,`** *union-style-enum-case-list*\ *union-style-enum-case* → *enum-case-name* *tuple-type?*\ *enum-name* → *identifier*\ *enum-case-name* → *identifier* *raw-value-style-enum* → **`enum`** *enum-name* *generic-parameter-clause?* *type-inheritance-clause* *generic-where-clause?* **`{`** *raw-value-style-enum-members* **`}`**\ *raw-value-style-enum-members* → *raw-value-style-enum-member* *raw-value-style-enum-members?*\ *raw-value-style-enum-member* → *declaration* | *raw-value-style-enum-case-clause* | *compiler-control-statement*\ *raw-value-style-enum-case-clause* → *attributes?* **`case`** *raw-value-style-enum-case-list*\ *raw-value-style-enum-case-list* → *raw-value-style-enum-case* | *raw-value-style-enum-case* **`,`** *raw-value-style-enum-case-list*\ *raw-value-style-enum-case* → *enum-case-name* *raw-value-assignment?*\ *raw-value-assignment* → **`=`** *raw-value-literal*\ *raw-value-literal* → *numeric-literal* | *static-string-literal* | *boolean-literal* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di struttura:** *struct-declaration* → *attributes?* *access-level-modifier?* **`struct`** *struct-name* *generic-parameter-clause?* *type-inheritance-clause?* *generic-where-clause?* *struct-body*\ *struct-name* → *identifier*\ *struct-body* → **`{`** *struct-members?* **`}`** *struct-members* → *struct-member* *struct-members?*\ *struct-member* → *declaration* | *compiler-control-statement* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di classe:** *class-declaration* → *attributes?* *access-level-modifier?* **`final`***?* **`class`** *class-name* *generic-parameter-clause?* *type-inheritance-clause?* *generic-where-clause?* *class-body*\ *class-declaration* → *attributes?* **`final`** *access-level-modifier?* **`class`** *class-name* *generic-parameter-clause?* *type-inheritance-clause?* *generic-where-clause?* *class-body*\ *class-name* → *identifier*\ *class-body* → **`{`** *class-members?* **`}`** *class-members* → *class-member* *class-members?*\ *class-member* → *declaration* | *compiler-control-statement* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di actor:** *actor-declaration* → *attributes?* *access-level-modifier?* **`actor`** *actor-name* *generic-parameter-clause?* *type-inheritance-clause?* *generic-where-clause?* *actor-body*\ *actor-name* → *identifier*\ *actor-body* → **`{`** *actor-members?* **`}`** *actor-members* → *actor-member* *actor-members?*\ *actor-member* → *declaration* | *compiler-control-statement* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di protocollo:** *protocol-declaration* → *attributes?* *access-level-modifier?* **`protocol`** *protocol-name* *type-inheritance-clause?* *generic-where-clause?* *protocol-body*\ *protocol-name* → *identifier*\ *protocol-body* → **`{`** *protocol-members?* **`}`** *protocol-members* → *protocol-member* *protocol-members?*\ *protocol-member* → *protocol-member-declaration* | *compiler-control-statement* *protocol-member-declaration* → *protocol-property-declaration*\ *protocol-member-declaration* → *protocol-method-declaration*\ *protocol-member-declaration* → *protocol-initializer-declaration*\ *protocol-member-declaration* → *protocol-subscript-declaration*\ *protocol-member-declaration* → *protocol-associated-type-declaration*\ *protocol-member-declaration* → *typealias-declaration* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di proprietà di un protocollo:** *protocol-property-declaration* → *variable-declaration-head* *variable-name* *type-annotation* *getter-setter-keyword-block* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di metodo di un protocollo:** *protocol-method-declaration* → *function-head* *function-name* *generic-parameter-clause?* *function-signature* *generic-where-clause?* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di inizializzatore di un protocollo:** *protocol-initializer-declaration* → *initializer-head* *generic-parameter-clause?* *parameter-clause* *throws-clause?* *generic-where-clause?*\ *protocol-initializer-declaration* → *initializer-head* *generic-parameter-clause?* *parameter-clause* **`rethrows`** *generic-where-clause?* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di subscript di un protocollo:** *protocol-subscript-declaration* → *subscript-head* *subscript-result* *generic-where-clause?* *getter-setter-keyword-block* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di tipo associato di un protocollo:** *protocol-associated-type-declaration* → *attributes?* *access-level-modifier?* **`associatedtype`** *typealias-name* *type-inheritance-clause?* *typealias-assignment?* *generic-where-clause?* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di inizializzatore:** *initializer-declaration* → *initializer-head* *generic-parameter-clause?* *parameter-clause* **`async`***?* *throws-clause?* *generic-where-clause?* *initializer-body*\ *initializer-declaration* → *initializer-head* *generic-parameter-clause?* *parameter-clause* **`async`***?* **`rethrows`** *generic-where-clause?* *initializer-body*\ *initializer-head* → *attributes?* *declaration-modifiers?* **`init`**\ *initializer-head* → *attributes?* *declaration-modifiers?* **`init`** **`?`**\ *initializer-head* → *attributes?* *declaration-modifiers?* **`init`** **`!`**\ *initializer-body* → *code-block* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di deinizializzatore:** *deinitializer-declaration* → *attributes?* **`deinit`** *code-block* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di estensione:** *extension-declaration* → *attributes?* *access-level-modifier?* **`extension`** *type-identifier* *type-inheritance-clause?* *generic-where-clause?* *extension-body*\ *extension-body* → **`{`** *extension-members?* **`}`** *extension-members* → *extension-member* *extension-members?*\ *extension-member* → *declaration* | *compiler-control-statement* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di subscript:** *subscript-declaration* → *subscript-head* *subscript-result* *generic-where-clause?* *code-block*\ *subscript-declaration* → *subscript-head* *subscript-result* *generic-where-clause?* *getter-setter-block*\ *subscript-declaration* → *subscript-head* *subscript-result* *generic-where-clause?* *getter-setter-keyword-block*\ *subscript-head* → *attributes?* *declaration-modifiers?* **`subscript`** *generic-parameter-clause?* *parameter-clause*\ *subscript-result* → **`->`** *attributes?* *type* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di macro:** *macro-declaration* → *macro-head* *identifier* *generic-parameter-clause?* *macro-signature* *macro-definition?* *generic-where-clause*\ *macro-head* → *attributes?* *declaration-modifiers?* **`macro`**\ *macro-signature* → *parameter-clause* *macro-function-signature-result?*\ *macro-function-signature-result* → **`->`** *type*\ *macro-definition* → **`=`** *expression* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di operatore:** *operator-declaration* → *prefix-operator-declaration* | *postfix-operator-declaration* | *infix-operator-declaration* *prefix-operator-declaration* → **`prefix`** **`operator`** *operator*\ *postfix-operator-declaration* → **`postfix`** **`operator`** *operator*\ *infix-operator-declaration* → **`infix`** **`operator`** *operator* *infix-operator-group?* *infix-operator-group* → **`:`** *precedence-group-name* {% endhint %} {% hint style="info" %} **Grammatica di una dichiarazione di gruppo di precedenza:** *precedence-group-declaration* → **`precedencegroup`** *precedence-group-name* **`{`** *precedence-group-attributes?* **`}`** *precedence-group-attributes* → *precedence-group-attribute* *precedence-group-attributes?*\ *precedence-group-attribute* → *precedence-group-relation*\ *precedence-group-attribute* → *precedence-group-assignment*\ *precedence-group-attribute* → *precedence-group-associativity* *precedence-group-relation* → **`higherThan`** **`:`** *precedence-group-names*\ *precedence-group-relation* → **`lowerThan`** **`:`** *precedence-group-names* *precedence-group-assignment* → **`assignment`** **`:`** *boolean-literal* *precedence-group-associativity* → **`associativity`** **`:`** **`left`**\ *precedence-group-associativity* → **`associativity`** **`:`** **`right`**\ *precedence-group-associativity* → **`associativity`** **`:`** **`none`** *precedence-group-names* → *precedence-group-name* | *precedence-group-name* **`,`** *precedence-group-names*\ *precedence-group-name* → *identifier* {% endhint %} {% hint style="info" %} **Grammatica di un modificatore di dichiarazione:** *declaration-modifier* → **`class`** | **`convenience`** | **`dynamic`** | **`final`** | **`infix`** | **`lazy`** | **`optional`** | **`override`** | **`postfix`** | **`prefix`** | **`required`** | **`static`** | **`unowned`** | **`unowned`** **`(`** **`safe`** **`)`** | **`unowned`** **`(`** **`unsafe`** **`)`** | **`weak`**\ *declaration-modifier* → *access-level-modifier*\ *declaration-modifier* → *mutation-modifier*\ *declaration-modifier* → *actor-isolation-modifier*\ *declaration-modifiers* → *declaration-modifier* *declaration-modifiers?* *access-level-modifier* → **`private`** | **`private`** **`(`** **`set`** **`)`**\ *access-level-modifier* → **`fileprivate`** | **`fileprivate`** **`(`** **`set`** **`)`**\ *access-level-modifier* → **`internal`** | **`internal`** **`(`** **`set`** **`)`**\ *access-level-modifier* → **`package`** | **`package`** **`(`** **`set`** **`)`**\ *access-level-modifier* → **`public`** | **`public`** **`(`** **`set`** **`)`**\ *access-level-modifier* → **`open`** | **`open`** **`(`** **`set`** **`)`** *mutation-modifier* → **`mutating`** | **`nonmutating`** *actor-isolation-modifier* → **`nonisolated`** {% endhint %} ## [Attributi](/riferimento-del-linguaggio/attributi.md) {% hint style="info" %} **Grammatica di un attributo:** *attribute* → **`@`** *attribute-name* *attribute-argument-clause?*\ *attribute-name* → *identifier*\ *attribute-argument-clause* → **`(`** *balanced-tokens?* **`)`**\ *attributes* → *attribute* *attributes?* *balanced-tokens* → *balanced-token* *balanced-tokens?*\ *balanced-token* → **`(`** *balanced-tokens?* **`)`**\ *balanced-token* → **`[`** *balanced-tokens?* **`]`**\ *balanced-token* → **`{`** *balanced-tokens?* **`}`**\ *balanced-token* → Any identifier, keyword, literal, or operator\ *balanced-token* → Any punctuation except **`(`**, **`)`**, **`[`**, **`]`**, **`{`**, or **`}`** {% endhint %} ## [Pattern](/riferimento-del-linguaggio/pattern.md) {% hint style="info" %} **Grammatica di un pattern:** *pattern* → *wildcard-pattern* *type-annotation?*\ *pattern* → *identifier-pattern* *type-annotation?*\ *pattern* → *value-binding-pattern*\ *pattern* → *tuple-pattern* *type-annotation?*\ *pattern* → *enum-case-pattern*\ *pattern* → *optional-pattern*\ *pattern* → *type-casting-pattern*\ *pattern* → *expression-pattern* {% endhint %} {% hint style="info" %} **Grammatica di un pattern wildcard:** *wildcard-pattern* → **`_`** {% endhint %} {% hint style="info" %} **Grammatica di un pattern identificatore:** *identifier-pattern* → *identifier* {% endhint %} {% hint style="info" %} **Grammatica di un pattern di value binding:** *value-binding-pattern* → **`var`** *pattern* | **`let`** *pattern* {% endhint %} {% hint style="info" %} **Grammatica di un pattern tupla:** *tuple-pattern* → **`(`** *tuple-pattern-element-list?* **`)`**\ *tuple-pattern-element-list* → *tuple-pattern-element* | *tuple-pattern-element* **`,`** *tuple-pattern-element-list*\ *tuple-pattern-element* → *pattern* | *identifier* **`:`** *pattern* {% endhint %} {% hint style="info" %} **Grammatica di un pattern dei casi di enumerazione:** *enum-case-pattern* → *type-identifier?* **`.`** *enum-case-name* *tuple-pattern?* {% endhint %} {% hint style="info" %} **Grammatica di un pattern opzionale:** *optional-pattern* → *identifier-pattern* **`?`** {% endhint %} {% hint style="info" %} **Grammatica di un pattern di type casting:** *type-casting-pattern* → *is-pattern* | *as-pattern*\ *is-pattern* → **`is`** *type*\ *as-pattern* → *pattern* **`as`** *type* {% endhint %} {% hint style="info" %} **Grammatica di un pattern espressione:** *expression-pattern* → *expression* {% endhint %} ## [Parametri e argomenti generici](/riferimento-del-linguaggio/parametri-e-argomenti-generici.md) {% hint style="info" %} **Grammatica di una clausola dei parametri generici:** *generic-parameter-clause* → **`<`** *generic-parameter-list* **`,`***?* **`>`**\ *generic-parameter-list* → *generic-parameter* | *generic-parameter* **`,`** *generic-parameter-list*\ *generic-parameter* → *type-name*\ *generic-parameter* → *type-name* **`:`** *type-identifier*\ *generic-parameter* → *type-name* **`:`** *protocol-composition-type*\ *generic-parameter* → **`let`** *type-name* **`:`** *type* \\ *generic-where-clause* → **`where`** *requirement-list*\ *requirement-list* → *requirement* | *requirement* **`,`** *requirement-list*\ *requirement* → *conformance-requirement* | *same-type-requirement* *conformance-requirement* → *type-identifier* **`:`** *type-identifier*\ *conformance-requirement* → *type-identifier* **`:`** *protocol-composition-type*\ *same-type-requirement* → *type-identifier* **`==`** *type*\ *same-type-requirement* → *type-identifier* **`==`** *signed-integer-literal* {% endhint %} {% hint style="info" %} **Grammatica di una clausola degli argomenti generici:** *generic-argument-clause* → **`<`** *generic-argument-list* **`,`***?* **`>`**\ *generic-argument-list* → *generic-argument* | *generic-argument* **`,`** *generic-argument-list*\ *generic-argument* → *type* | *signed-integer-literal* {% endhint %}