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| author | Timothee Cour <timothee.cour2@gmail.com> | 2021-02-04 15:39:19 -0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-02-04 15:39:19 -0800 |
| commit | ae9ba260f62b4ae3f7ab78be9eef544ff7dd72f2 (patch) | |
| tree | f084ae4f13194dbc715f940e5ac8bc5777e88666 /lib/std/wrapnils.nim | |
| parent | 2a60974ede6ce9176cfb3b4c74a6ae2ff84ba6f5 (diff) | |
| download | Nim-ae9ba260f62b4ae3f7ab78be9eef544ff7dd72f2.tar.gz | |
clarify docs for wrapnils (#16929)
Co-authored-by: Dominik Picheta <dominikpicheta@googlemail.com>
Diffstat (limited to 'lib/std/wrapnils.nim')
| -rw-r--r-- | lib/std/wrapnils.nim | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/lib/std/wrapnils.nim b/lib/std/wrapnils.nim index 71205c887..5b2dd9769 100644 --- a/lib/std/wrapnils.nim +++ b/lib/std/wrapnils.nim @@ -19,8 +19,13 @@ runnableExamples: assert ?.f2.x1 == "a" # same as f2.x1 (no nil LHS in this chain) assert ?.Foo(x1: "a").x1 == "a" # can use constructor inside - # when you know a sub-expression is not nil, you can scope it as follows: - assert ?.(f2.x2.x2).x3[] == 0 # because `f` is nil + # when you know a sub-expression doesn't involve a `nil` (e.g. `f2.x2.x2`), + # you can scope it as follows: + assert ?.(f2.x2.x2).x3[] == 0 + + assert (?.f2.x2.x2).x3 == nil # this terminates ?. early + import segfaults # enable `NilAccessDefect` exceptions + doAssertRaises(NilAccessDefect): echo (?.f2.x2.x2).x3[] type Wrapnil[T] = object valueImpl: T |