mirror of
https://github.com/nim-lang/Nim.git
synced 2025-12-28 17:04:41 +00:00
7d6cbf290a
* Error -> Defect for defects The distinction between Error and Defect is subjective, context-dependent and somewhat arbitrary, so when looking at an exception, it's hard to guess what it is - this happens often when looking at a `raises` list _without_ opening the corresponding definition and digging through layers of inheritance. With the help of a little consistency in naming, it's at least possible to start disentangling the two error types and the standard lib can set a good example here.
83 lines
1.9 KiB
Nim
83 lines
1.9 KiB
Nim
import std/wrapnils
|
|
|
|
const wrapnilExtendedExports = declared(wrapnil)
|
|
# for now, wrapnil, isValid, unwrap are not exported
|
|
|
|
proc checkNotZero(x: float): float =
|
|
doAssert x != 0
|
|
x
|
|
|
|
var witness = 0
|
|
|
|
proc main() =
|
|
type Bar = object
|
|
b1: int
|
|
b2: ptr string
|
|
|
|
type Foo = ref object
|
|
x1: float
|
|
x2: Foo
|
|
x3: string
|
|
x4: Bar
|
|
x5: seq[int]
|
|
x6: ptr Bar
|
|
x7: array[2, string]
|
|
x8: seq[int]
|
|
x9: ref Bar
|
|
|
|
type Gook = ref object
|
|
foo: Foo
|
|
|
|
proc fun(a: Bar): auto = a.b2
|
|
|
|
var a: Foo
|
|
var x6 = create(Bar)
|
|
x6.b1 = 42
|
|
var a2 = Foo(x1: 1.0, x5: @[10, 11], x6: x6)
|
|
var a3 = Foo(x1: 1.2, x3: "abc")
|
|
a3.x2 = a3
|
|
|
|
var gook = Gook(foo: a)
|
|
|
|
proc initFoo(x1: float): auto =
|
|
witness.inc
|
|
result = Foo(x1: x1)
|
|
|
|
doAssert ?.a.x2.x2.x1 == 0.0
|
|
doAssert ?.a3.x2.x2.x1 == 1.2
|
|
doAssert ?.a3.x2.x2.x3[1] == 'b'
|
|
|
|
doAssert ?.a3.x2.x2.x5.len == 0
|
|
doAssert a3.x2.x2.x3.len == 3
|
|
|
|
when wrapnilExtendedExports:
|
|
# example calling wrapnil directly, with and without unwrap
|
|
doAssert a3.wrapnil.x2.x2.x3.len == wrapnil(3)
|
|
doAssert a3.wrapnil.x2.x2.x3.len.unwrap == 3
|
|
doAssert a2.wrapnil.x4.isValid
|
|
doAssert not a.wrapnil.x4.isValid
|
|
|
|
doAssert ?.a.x2.x2.x3[1] == default(char)
|
|
# here we only apply wrapnil around gook.foo, not gook (and assume gook is not nil)
|
|
doAssert ?.(gook.foo).x2.x2.x1 == 0.0
|
|
|
|
doAssert ?.a2.x6[] == Bar(b1: 42) # deref for ptr Bar
|
|
|
|
doAssert ?.a2.x1.checkNotZero == 1.0
|
|
doAssert a == nil
|
|
# shows that checkNotZero won't be called if a nil is found earlier in chain
|
|
doAssert ?.a.x1.checkNotZero == 0.0
|
|
|
|
# checks that a chain without nil but with an empty seq still throws IndexDefect
|
|
doAssertRaises(IndexDefect): discard ?.a2.x8[3]
|
|
|
|
# make sure no double evaluation bug
|
|
doAssert witness == 0
|
|
doAssert ?.initFoo(1.3).x1 == 1.3
|
|
doAssert witness == 1
|
|
|
|
# here, it's used twice, to deref `ref Bar` and then `ptr string`
|
|
doAssert ?.a.x9[].fun[] == ""
|
|
|
|
main()
|