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90 lines
3.1 KiB
Text
90 lines
3.1 KiB
Text
interface Bool
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exposes [ not, and, or, xor, isEq, isNotEq ]
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imports []
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## Returns `False` when given `True`, and vice versa.
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not : [True, False] -> [True, False]
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## Returns `True` when given `True` and `True`, and `False` when either argument is `False`.
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##
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## `a && b` is shorthand for `Bool.and a b`
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##
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## >>> True && True
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##
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## >>> True && False
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##
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## >>> False && True
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##
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## >>> False && False
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##
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## ## Performance Notes
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##
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## In some languages, `&&` and `||` are special-cased in the compiler to skip
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## evaluating the expression after the operator under certain circumstances.
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## For example, in some languages, `enablePets && likesDogs user` would compile
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## to the equivalent of:
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##
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## if enablePets then
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## likesDogs user
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## else
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## False
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##
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## In Roc, however, `&&` and `||` are not special. They work the same way as
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## other functions. Conditionals like `if` and `when` have a performance cost,
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## and sometimes calling a function like `likesDogs user` can be faster across
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## the board than doing an `if` to decide whether to skip calling it.
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##
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## (Naturally, if you expect the `if` to improve performance, you can always add
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## one explicitly!)
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and : Bool, Bool -> Bool
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## Returns `True` when given `True` for either argument, and `False` only when given `False` and `False`.
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##
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## `a || b` is shorthand for `Bool.or a b`.
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##
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## >>> True || True
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#
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## >>> True || False
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#
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## >>> False || True
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##
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## >>> False || False
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##
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## ## Performance Notes
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##
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## In some languages, `&&` and `||` are special-cased in the compiler to skip
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## evaluating the expression after the operator under certain circumstances.
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## # In Roc, this is not the case. See the performance notes for #Bool.and for details.
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or : Bool, Bool -> Bool
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## Exclusive or
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xor : Bool, Bool -> Bool
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## Returns `True` if the two values are *structurally equal*, and `False` otherwise.
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##
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## `a == b` is shorthand for `Bool.isEq a b`
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##
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## Structural equality works as follows:
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##
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## 1. #Int and #Float values are equal if their numbers are equal.
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## 2. Records are equal if all their fields are equal.
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## 3. Global tags are equal if they are the same tag, and also their contents (if any) are equal.
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## 4. Private tags are equal if they are the same tag, in the same module, and also their contents (if any) are equal.
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## 5. Collections (#String, #List, #Map, #Set, and #Bytes) are equal if they are the same length, and also all their corresponding elements are equal.
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##
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## Note that `isEq` takes `'val` instead of `val`, which means `isEq` does not
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## accept arguments whose types contain functions.
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# TODO: removed `'` from signature because parser does not support it yet
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# Original signature: `isEq : 'val, 'val -> Bool`
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isEq : val, val -> Bool
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## Calls #eq on the given values, then calls #not on the result.
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##
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## `a != b` is shorthand for `Bool.isNotEq a b`
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##
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## Note that `isNotEq` takes `'val` instead of `val`, which means `isNotEq` does not
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## accept arguments whose types contain functions.
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# TODO: removed `'` from signature because parser does not support it yet
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# Original signature: `isNotEq : 'val, 'val -> Bool`
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isNotEq : val, val -> Bool
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