110 lines
2.8 KiB
Nim
110 lines
2.8 KiB
Nim
import
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macros
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template init*(lvalue: var auto) =
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mixin init
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lvalue = init(type(lvalue))
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template init*(lvalue: var auto, a1: auto)=
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mixin init
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lvalue = init(type(lvalue), a1)
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template init*(lvalue: var auto, a1, a2: auto) =
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mixin init
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lvalue = init(type(lvalue), a1, a2)
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template init*(lvalue: var auto, a1, a2, a3: auto) =
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mixin init
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lvalue = init(type(lvalue), a1, a2, a3)
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when not declared(default):
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proc default*(T: type): T = discard
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proc toArray*[T](N: static int, data: openarray[T]): array[N, T] =
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doAssert data.len == N
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copyMem(addr result[0], unsafeAddr data[0], N)
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template anonConst*(val: untyped): untyped =
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const c = val
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c
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func declval*(T: type): T {.compileTime.} =
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## `declval` denotes an anonymous expression of a particular
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## type. It can be used in situations where you want to determine
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## the type of an overloaded call in `typeof` expressions.
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##
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## Example:
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## ```
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## type T = typeof foo(declval(string), declval(var int))
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## ```
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##
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## Please note that `declval` has two advantages over `default`:
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##
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## 1. It can return expressions with proper `var` or `lent` types.
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##
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## 2. It will work for types that lack a valid default value due
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## to `not nil` or `requiresInit` requirements.
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##
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doAssert false,
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"declval should be used only in `typeof` expressions and concepts"
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default(ptr T)[]
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when not compiles(len((1, 2))):
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import typetraits
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func len*(x: tuple): int =
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arity(type(x))
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# Get an object's base type, as a cstring. Ref objects will have an ":ObjectType"
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# suffix.
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# From: https://gist.github.com/stefantalpalaru/82dc71bb547d6f9178b916e3ed5b527d
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proc baseType*(obj: RootObj): cstring =
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when not defined(nimTypeNames):
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raiseAssert("you need to compile this with '-d:nimTypeNames'")
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else:
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{.emit: "result = `obj`->m_type->name;".}
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proc baseType*(obj: ref RootObj): cstring =
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obj[].baseType
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when false:
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# TODO: Implementing this doesn't seem possible at the moment.
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#
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# When given enum like:
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#
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# type WithoutHoles2 = enum
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# A2 = 2, B2 = 3, C2 = 4
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#
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# ...the code below will print:
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#
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# EnumTy
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# Empty
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# Sym "A2"
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# Sym "B2"
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# Sym "C2"
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#
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macro hasHoles*(T: type[enum]): bool =
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let t = getType(T)[1]
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echo t.treeRepr
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return newLit(true)
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func checkedEnumAssign*[E: enum, I: SomeInteger](res: var E, value: I): bool =
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## This function can be used to safely assign a tainted integer value (coming
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## from untrusted source) to an enum variable. The function will return `true`
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## if the integer value is within the acceped values of the enum and `false`
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## otherwise.
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# TODO: Enums with holes are not supported yet
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# static: doAssert(not hasHoles(E))
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when I is SomeSignedInt or low(E).int > 0:
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if value < I(low(E)):
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return false
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if value > I(high(E)):
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return false
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res = E value
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return true
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