1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554
|
<!-- This file is automatically generated with generate-swift-format. Do not edit! -->
# `swift-format` Lint and Format Rules
Use the rules below in the `rules` block of your `.swift-format`
configuration file, as described in
[Configuration](Configuration.md). All of these rules can be
applied in the linter, but only some of them can format your source code
automatically.
Here's the list of available rules:
- [AllPublicDeclarationsHaveDocumentation](#AllPublicDeclarationsHaveDocumentation)
- [AlwaysUseLiteralForEmptyCollectionInit](#AlwaysUseLiteralForEmptyCollectionInit)
- [AlwaysUseLowerCamelCase](#AlwaysUseLowerCamelCase)
- [AmbiguousTrailingClosureOverload](#AmbiguousTrailingClosureOverload)
- [BeginDocumentationCommentWithOneLineSummary](#BeginDocumentationCommentWithOneLineSummary)
- [DoNotUseSemicolons](#DoNotUseSemicolons)
- [DontRepeatTypeInStaticProperties](#DontRepeatTypeInStaticProperties)
- [FileScopedDeclarationPrivacy](#FileScopedDeclarationPrivacy)
- [FullyIndirectEnum](#FullyIndirectEnum)
- [GroupNumericLiterals](#GroupNumericLiterals)
- [IdentifiersMustBeASCII](#IdentifiersMustBeASCII)
- [NeverForceUnwrap](#NeverForceUnwrap)
- [NeverUseForceTry](#NeverUseForceTry)
- [NeverUseImplicitlyUnwrappedOptionals](#NeverUseImplicitlyUnwrappedOptionals)
- [NoAccessLevelOnExtensionDeclaration](#NoAccessLevelOnExtensionDeclaration)
- [NoAssignmentInExpressions](#NoAssignmentInExpressions)
- [NoBlockComments](#NoBlockComments)
- [NoCasesWithOnlyFallthrough](#NoCasesWithOnlyFallthrough)
- [NoEmptyTrailingClosureParentheses](#NoEmptyTrailingClosureParentheses)
- [NoLabelsInCasePatterns](#NoLabelsInCasePatterns)
- [NoLeadingUnderscores](#NoLeadingUnderscores)
- [NoParensAroundConditions](#NoParensAroundConditions)
- [NoPlaygroundLiterals](#NoPlaygroundLiterals)
- [NoVoidReturnOnFunctionSignature](#NoVoidReturnOnFunctionSignature)
- [OmitExplicitReturns](#OmitExplicitReturns)
- [OneCasePerLine](#OneCasePerLine)
- [OneVariableDeclarationPerLine](#OneVariableDeclarationPerLine)
- [OnlyOneTrailingClosureArgument](#OnlyOneTrailingClosureArgument)
- [OrderedImports](#OrderedImports)
- [ReplaceForEachWithForLoop](#ReplaceForEachWithForLoop)
- [ReturnVoidInsteadOfEmptyTuple](#ReturnVoidInsteadOfEmptyTuple)
- [TypeNamesShouldBeCapitalized](#TypeNamesShouldBeCapitalized)
- [UseEarlyExits](#UseEarlyExits)
- [UseExplicitNilCheckInConditions](#UseExplicitNilCheckInConditions)
- [UseLetInEveryBoundCaseVariable](#UseLetInEveryBoundCaseVariable)
- [UseShorthandTypeNames](#UseShorthandTypeNames)
- [UseSingleLinePropertyGetter](#UseSingleLinePropertyGetter)
- [UseSynthesizedInitializer](#UseSynthesizedInitializer)
- [UseTripleSlashForDocumentationComments](#UseTripleSlashForDocumentationComments)
- [UseWhereClausesInForLoops](#UseWhereClausesInForLoops)
- [ValidateDocumentationComments](#ValidateDocumentationComments)
### AllPublicDeclarationsHaveDocumentation
All public or open declarations must have a top-level documentation comment.
Lint: If a public declaration is missing a documentation comment, a lint error is raised.
`AllPublicDeclarationsHaveDocumentation` is a linter-only rule.
### AlwaysUseLiteralForEmptyCollectionInit
Never use `[<Type>]()` syntax. In call sites that should be replaced with `[]`,
for initializations use explicit type combined with empty array literal `let _: [<Type>] = []`
Static properties of a type that return that type should not include a reference to their type.
Lint: Non-literal empty array initialization will yield a lint error.
Format: All invalid use sites would be related with empty literal (with or without explicit type annotation).
`AlwaysUseLiteralForEmptyCollectionInit` rule can format your code automatically.
### AlwaysUseLowerCamelCase
All values should be written in lower camel-case (`lowerCamelCase`).
Underscores (except at the beginning of an identifier) are disallowed.
This rule does not apply to test code, defined as code which:
* Contains the line `import XCTest`
Lint: If an identifier contains underscores or begins with a capital letter, a lint error is
raised.
`AlwaysUseLowerCamelCase` is a linter-only rule.
### AmbiguousTrailingClosureOverload
Overloads with only a closure argument should not be disambiguated by parameter labels.
Lint: If two overloaded functions with one closure parameter appear in the same scope, a lint
error is raised.
`AmbiguousTrailingClosureOverload` is a linter-only rule.
### BeginDocumentationCommentWithOneLineSummary
All documentation comments must begin with a one-line summary of the declaration.
Lint: If a comment does not begin with a single-line summary, a lint error is raised.
`BeginDocumentationCommentWithOneLineSummary` is a linter-only rule.
### DoNotUseSemicolons
Semicolons should not be present in Swift code.
Lint: If a semicolon appears anywhere, a lint error is raised.
Format: All semicolons will be replaced with line breaks.
`DoNotUseSemicolons` rule can format your code automatically.
### DontRepeatTypeInStaticProperties
Static properties of a type that return that type should not include a reference to their type.
"Reference to their type" means that the property name includes part, or all, of the type. If
the type contains a namespace (i.e. `UIColor`) the namespace is ignored;
`public class var redColor: UIColor` would trigger this rule.
Lint: Static properties of a type that return that type will yield a lint error.
`DontRepeatTypeInStaticProperties` is a linter-only rule.
### FileScopedDeclarationPrivacy
Declarations at file scope with effective private access should be consistently declared as
either `fileprivate` or `private`, determined by configuration.
Lint: If a file-scoped declaration has formal access opposite to the desired access level in the
formatter's configuration, a lint error is raised.
Format: File-scoped declarations that have formal access opposite to the desired access level in
the formatter's configuration will have their access level changed.
`FileScopedDeclarationPrivacy` rule can format your code automatically.
### FullyIndirectEnum
If all cases of an enum are `indirect`, the entire enum should be marked `indirect`.
Lint: If every case of an enum is `indirect`, but the enum itself is not, a lint error is
raised.
Format: Enums where all cases are `indirect` will be rewritten such that the enum is marked
`indirect`, and each case is not.
`FullyIndirectEnum` rule can format your code automatically.
### GroupNumericLiterals
Numeric literals should be grouped with `_`s to delimit common separators.
Specifically, decimal numeric literals should be grouped every 3 numbers, hexadecimal every 4,
and binary every 8.
Lint: If a numeric literal is too long and should be grouped, a lint error is raised.
Format: All numeric literals that should be grouped will have `_`s inserted where appropriate.
TODO: Minimum numeric literal length bounds and numeric groupings have been selected arbitrarily;
these could be reevaluated.
TODO: Handle floating point literals.
`GroupNumericLiterals` rule can format your code automatically.
### IdentifiersMustBeASCII
All identifiers must be ASCII.
Lint: If an identifier contains non-ASCII characters, a lint error is raised.
`IdentifiersMustBeASCII` is a linter-only rule.
### NeverForceUnwrap
Force-unwraps are strongly discouraged and must be documented.
This rule does not apply to test code, defined as code which:
* Contains the line `import XCTest`
Lint: If a force unwrap is used, a lint warning is raised.
`NeverForceUnwrap` is a linter-only rule.
### NeverUseForceTry
Force-try (`try!`) is forbidden.
This rule does not apply to test code, defined as code which:
* Contains the line `import XCTest`
Lint: Using `try!` results in a lint error.
TODO: Create exception for NSRegularExpression
`NeverUseForceTry` is a linter-only rule.
### NeverUseImplicitlyUnwrappedOptionals
Implicitly unwrapped optionals (e.g. `var s: String!`) are forbidden.
Certain properties (e.g. `@IBOutlet`) tied to the UI lifecycle are ignored.
This rule does not apply to test code, defined as code which:
* Contains the line `import XCTest`
TODO: Create exceptions for other UI elements (ex: viewDidLoad)
Lint: Declaring a property with an implicitly unwrapped type yields a lint error.
`NeverUseImplicitlyUnwrappedOptionals` is a linter-only rule.
### NoAccessLevelOnExtensionDeclaration
Specifying an access level for an extension declaration is forbidden.
Lint: Specifying an access level for an extension declaration yields a lint error.
Format: The access level is removed from the extension declaration and is added to each
declaration in the extension; declarations with redundant access levels (e.g.
`internal`, as that is the default access level) have the explicit access level removed.
`NoAccessLevelOnExtensionDeclaration` rule can format your code automatically.
### NoAssignmentInExpressions
Assignment expressions must be their own statements.
Assignment should not be used in an expression context that expects a `Void` value. For example,
assigning a variable within a `return` statement existing a `Void` function is prohibited.
Lint: If an assignment expression is found in a position other than a standalone statement, a
lint finding is emitted.
Format: A `return` statement containing an assignment expression is expanded into two separate
statements.
`NoAssignmentInExpressions` rule can format your code automatically.
### NoBlockComments
Block comments should be avoided in favor of line comments.
Lint: If a block comment appears, a lint error is raised.
`NoBlockComments` is a linter-only rule.
### NoCasesWithOnlyFallthrough
Cases that contain only the `fallthrough` statement are forbidden.
Lint: Cases containing only the `fallthrough` statement yield a lint error.
Format: The fallthrough `case` is added as a prefix to the next case unless the next case is
`default`; in that case, the fallthrough `case` is deleted.
`NoCasesWithOnlyFallthrough` rule can format your code automatically.
### NoEmptyTrailingClosureParentheses
Function calls with no arguments and a trailing closure should not have empty parentheses.
Lint: If a function call with a trailing closure has an empty argument list with parentheses,
a lint error is raised.
Format: Empty parentheses in function calls with trailing closures will be removed.
`NoEmptyTrailingClosureParentheses` rule can format your code automatically.
### NoLabelsInCasePatterns
Redundant labels are forbidden in case patterns.
In practice, *all* case pattern labels should be redundant.
Lint: Using a label in a case statement yields a lint error unless the label does not match the
binding identifier.
Format: Redundant labels in case patterns are removed.
`NoLabelsInCasePatterns` rule can format your code automatically.
### NoLeadingUnderscores
Identifiers in declarations and patterns should not have leading underscores.
This is intended to avoid certain antipatterns; `self.member = member` should be preferred to
`member = _member` and the leading underscore should not be used to signal access level.
This rule intentionally checks only the parameter variable names of a function declaration, not
the parameter labels. It also only checks identifiers at the declaration site, not at usage
sites.
Lint: Declaring an identifier with a leading underscore yields a lint error.
`NoLeadingUnderscores` is a linter-only rule.
### NoParensAroundConditions
Enforces rules around parentheses in conditions or matched expressions.
Parentheses are not used around any condition of an `if`, `guard`, or `while` statement, or
around the matched expression in a `switch` statement.
Lint: If a top-most expression in a `switch`, `if`, `guard`, or `while` statement is surrounded
by parentheses, and it does not include a function call with a trailing closure, a lint
error is raised.
Format: Parentheses around such expressions are removed, if they do not cause a parse ambiguity.
Specifically, parentheses are allowed if and only if the expression contains a function
call with a trailing closure.
`NoParensAroundConditions` rule can format your code automatically.
### NoPlaygroundLiterals
The playground literals (`#colorLiteral`, `#fileLiteral`, and `#imageLiteral`) are forbidden.
Lint: Using a playground literal will yield a lint error with a suggestion of an API to replace
it.
`NoPlaygroundLiterals` is a linter-only rule.
### NoVoidReturnOnFunctionSignature
Functions that return `()` or `Void` should omit the return signature.
Lint: Function declarations that explicitly return `()` or `Void` will yield a lint error.
Format: Function declarations with explicit returns of `()` or `Void` will have their return
signature stripped.
`NoVoidReturnOnFunctionSignature` rule can format your code automatically.
### OmitExplicitReturns
Single-expression functions, closures, subscripts can omit `return` statement.
Lint: `func <name>() { return ... }` and similar single expression constructs will yield a lint error.
Format: `func <name>() { return ... }` constructs will be replaced with
equivalent `func <name>() { ... }` constructs.
`OmitExplicitReturns` rule can format your code automatically.
### OneCasePerLine
Each enum case with associated values or a raw value should appear in its own case declaration.
Lint: If a single `case` declaration declares multiple cases, and any of them have associated
values or raw values, a lint error is raised.
Format: All case declarations with associated values or raw values will be moved to their own
case declarations.
`OneCasePerLine` rule can format your code automatically.
### OneVariableDeclarationPerLine
Each variable declaration, with the exception of tuple destructuring, should
declare 1 variable.
Lint: If a variable declaration declares multiple variables, a lint error is
raised.
Format: If a variable declaration declares multiple variables, it will be
split into multiple declarations, each declaring one of the variables, as
long as the result would still be syntactically valid.
`OneVariableDeclarationPerLine` rule can format your code automatically.
### OnlyOneTrailingClosureArgument
Function calls should never mix normal closure arguments and trailing closures.
Lint: If a function call with a trailing closure also contains a non-trailing closure argument,
a lint error is raised.
`OnlyOneTrailingClosureArgument` is a linter-only rule.
### OrderedImports
Imports must be lexicographically ordered and logically grouped at the top of each source file.
The order of the import groups is 1) regular imports, 2) declaration imports, and 3) @testable
imports. These groups are separated by a single blank line. Blank lines in between the import
declarations are removed.
Lint: If an import appears anywhere other than the beginning of the file it resides in,
not lexicographically ordered, or not in the appropriate import group, a lint error is
raised.
Format: Imports will be reordered and grouped at the top of the file.
`OrderedImports` rule can format your code automatically.
### ReplaceForEachWithForLoop
Replace `forEach` with `for-in` loop unless its argument is a function reference.
Lint: invalid use of `forEach` yield will yield a lint error.
`ReplaceForEachWithForLoop` is a linter-only rule.
### ReturnVoidInsteadOfEmptyTuple
Return `Void`, not `()`, in signatures.
Note that this rule does *not* apply to function declaration signatures in order to avoid
conflicting with `NoVoidReturnOnFunctionSignature`.
Lint: Returning `()` in a signature yields a lint error.
Format: `-> ()` is replaced with `-> Void`
`ReturnVoidInsteadOfEmptyTuple` rule can format your code automatically.
### TypeNamesShouldBeCapitalized
`struct`, `class`, `enum` and `protocol` declarations should have a capitalized name.
Lint: Types with un-capitalized names will yield a lint error.
`TypeNamesShouldBeCapitalized` is a linter-only rule.
### UseEarlyExits
Early exits should be used whenever possible.
This means that `if ... else { return/throw/break/continue }` constructs should be replaced by
`guard ... else { return/throw/break/continue }` constructs in order to keep indentation levels
low. Specifically, code of the following form:
```swift
if condition {
trueBlock
} else {
falseBlock
return/throw/break/continue
}
```
will be transformed into:
```swift
guard condition else {
falseBlock
return/throw/break/continue
}
trueBlock
```
Lint: `if ... else { return/throw/break/continue }` constructs will yield a lint error.
Format: `if ... else { return/throw/break/continue }` constructs will be replaced with
equivalent `guard ... else { return/throw/break/continue }` constructs.
`UseEarlyExits` rule can format your code automatically.
### UseExplicitNilCheckInConditions
When checking an optional value for `nil`-ness, prefer writing an explicit `nil` check rather
than binding and immediately discarding the value.
For example, `if let _ = someValue { ... }` is forbidden. Use `if someValue != nil { ... }`
instead.
Lint: `let _ = expr` inside a condition list will yield a lint error.
Format: `let _ = expr` inside a condition list will be replaced by `expr != nil`.
`UseExplicitNilCheckInConditions` rule can format your code automatically.
### UseLetInEveryBoundCaseVariable
Every variable bound in a `case` pattern must have its own `let/var`.
For example, `case let .identifier(x, y)` is forbidden. Use
`case .identifier(let x, let y)` instead.
Lint: `case let .identifier(...)` will yield a lint error.
`UseLetInEveryBoundCaseVariable` is a linter-only rule.
### UseShorthandTypeNames
Shorthand type forms must be used wherever possible.
Lint: Using a non-shorthand form (e.g. `Array<Element>`) yields a lint error unless the long
form is necessary (e.g. `Array<Element>.Index` cannot be shortened today.)
Format: Where possible, shorthand types replace long form types; e.g. `Array<Element>` is
converted to `[Element]`.
`UseShorthandTypeNames` rule can format your code automatically.
### UseSingleLinePropertyGetter
Read-only computed properties must use implicit `get` blocks.
Lint: Read-only computed properties with explicit `get` blocks yield a lint error.
Format: Explicit `get` blocks are rendered implicit by removing the `get`.
`UseSingleLinePropertyGetter` rule can format your code automatically.
### UseSynthesizedInitializer
When possible, the synthesized `struct` initializer should be used.
This means the creation of a (non-public) memberwise initializer with the same structure as the
synthesized initializer is forbidden.
Lint: (Non-public) memberwise initializers with the same structure as the synthesized
initializer will yield a lint error.
`UseSynthesizedInitializer` is a linter-only rule.
### UseTripleSlashForDocumentationComments
Documentation comments must use the `///` form.
This is similar to `NoBlockComments` but is meant to prevent documentation block comments.
Lint: If a doc block comment appears, a lint error is raised.
Format: If a doc block comment appears on its own on a line, or if a doc block comment spans
multiple lines without appearing on the same line as code, it will be replaced with
multiple doc line comments.
`UseTripleSlashForDocumentationComments` rule can format your code automatically.
### UseWhereClausesInForLoops
`for` loops that consist of a single `if` statement must use `where` clauses instead.
Lint: `for` loops that consist of a single `if` statement yield a lint error.
Format: `for` loops that consist of a single `if` statement have the conditional of that
statement factored out to a `where` clause.
`UseWhereClausesInForLoops` rule can format your code automatically.
### ValidateDocumentationComments
Documentation comments must be complete and valid.
"Command + Option + /" in Xcode produces a minimal valid documentation comment.
Lint: Documentation comments that are incomplete (e.g. missing parameter documentation) or
invalid (uses `Parameters` when there is only one parameter) will yield a lint error.
`ValidateDocumentationComments` is a linter-only rule.
|