diff options
| author | Nobuyoshi Nakada <[email protected]> | 2024-05-12 16:23:00 +0900 |
|---|---|---|
| committer | Nobuyoshi Nakada <[email protected]> | 2024-05-12 16:23:00 +0900 |
| commit | b911d2222f907d3fad397938e8f513ecfb4635b8 (patch) | |
| tree | 4b1dbb09896ae3ceb454d34a7532043ed898ad56 /doc/syntax/pattern_matching.rdoc | |
| parent | 5695c5df95460ed9949e1c8f8ca89b4a5c5cc4dd (diff) | |
[Bug #20482] [DOC] Clarify about pattern maching guard clause
Guard clauses can only be used in `case` pattern matching statements,
not in `=>`/`in` operators.
Diffstat (limited to 'doc/syntax/pattern_matching.rdoc')
| -rw-r--r-- | doc/syntax/pattern_matching.rdoc | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/doc/syntax/pattern_matching.rdoc b/doc/syntax/pattern_matching.rdoc index e49c09a1f8..6a30380f46 100644 --- a/doc/syntax/pattern_matching.rdoc +++ b/doc/syntax/pattern_matching.rdoc @@ -422,7 +422,8 @@ These core and library classes implement deconstruction: == Guard clauses -+if+ can be used to attach an additional condition (guard clause) when the pattern matches. This condition may use bound variables: ++if+ can be used to attach an additional condition (guard clause) when the pattern matches in +case+/+in+ expressions. +This condition may use bound variables: case [1, 2] in a, b if b == a*2 @@ -450,6 +451,11 @@ These core and library classes implement deconstruction: end #=> "matched" +Note that <code>=></code> and +in+ operator can not have a guard clause. +The following examples is parsed as a standalone expression with modifier +if+. + + [1, 2] in a, b if b == a*2 + == Appendix A. Pattern syntax Approximate syntax is: |