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| author | metagn <metagngn@gmail.com> | 2023-03-30 16:34:42 +0300 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-03-30 15:34:42 +0200 |
| commit | ecf9efa3977f95aed5229ab79cd6ac4799a32a4c (patch) | |
| tree | 4416d5c0109d308f861afc6d43fb28a168bcc18f /doc | |
| parent | 51ced0d68477e4d2ae5fa8183579922ec47cd318 (diff) | |
| download | Nim-ecf9efa3977f95aed5229ab79cd6ac4799a32a4c.tar.gz | |
document general use of `_`, error message, fixes (#21584)
* document general use of `_`, error message, fixes fixes #20687, fixes #21435 Documentation and changelog updated to clarify new universal behavior of `_`. Also new error message for attempting to use `_`, new tests, and fixes with overloadable symbols and implicit generics. * add test for #21435
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/manual.md | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/doc/manual.md b/doc/manual.md index 1fd35e7b3..850a04b0d 100644 --- a/doc/manual.md +++ b/doc/manual.md @@ -3076,6 +3076,19 @@ when they are declared. The only exception to this is if the `{.importc.}` pragma (or any of the other `importX` pragmas) is applied, in this case the value is expected to come from native code, typically a C/C++ `const`. +Special identifier `_` (underscore) +----------------------------------- + +The identifier `_` has a special meaning in declarations. +Any definition with the name `_` will not be added to scope, meaning the +definition is evaluated, but cannot be used. As a result the name `_` can be +indefinitely redefined. + + ```nim + let _ = 123 + echo _ # error + let _ = 456 # compiles + ``` Tuple unpacking --------------- |