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case 1
in 1
end
case 1
in 1
:one
else
nil
end
if true
# 0
case
# 1
# 2
a # 3
# 4
in
# 5
# 6
b # 7
# 8
:b # 9
# 10
else # 11
# 12
:c # 13
# 14
end # 15
# 16
end
## Standalone matches (assignments)
1 => a
1 in a
# 0
[
a, # 1
] in
# 2
# 3
b # 4
# 5
## Array patterns
xs => []
xs in [a, b, c]
xs => a, b, c
xs in a, b, *cs, d
xs => Foo[a, b, c]
xs => Foo(d, e, *f)
xs => [a, *]
xs => *, a
xs => [*]
xs => a, b
xs => [a, ]
xs => *a
# Wrap by brackets automatically to avoid syntax error after stripping semicolons.
xs => [a, ]
xs => [a, *]
case xs
in [0, ]
nil
end
xs =>
# 0
# 1
Foo::
# 2
# 3
Bar[
# 4
# 5
a, # 6
# 7
b, # 8
# 9
*cs, # 10
# 11
d # 12
# 13
] # 14
# 15
xs => [
a, # a
b, # b
c,
] # c
# d
xs => [
a,
b,
*cs # no comma
]
xs => [
a, # a
b,
*cs,
d # no comma
]
## Find patterns
xs in [*, x, *]
xs => *a, x, _y, z, *b
xs =>
# 0
# 1
[
*a, # 2
# 3
b, # 4
# 5
c, # 6
# 7
*d
] # 8
# 9
## Hash patterns
hash in {}
hash => { a:, b: { c: } }
hash in a:, b: { c: }
hash => { a: 1, b: [c, *], d: }
hash in { a:, **b }
hash => { a:, ** }
hash in { ** }
hash => **all
hash =>
# 0
# 1
{
# 2
# 3
a:
# 4
# 5
:b, # 6
# 7
} # 8
# 9
hash =>
# 0
# 1
{
a:, # 2
# 3
**b
} # 4
# 5
## Pinned expressions / variables
v => ^(1 + 2)
v in ^(nil)
v => { a: ^(!true), b: [*, ^(Foo.bar)] }
v =>
# 0
# 1
^(
# 2
# 3
a * (b + c)) # 4
# 5
v => ^a
v => [a, ^b, *c]
v in ^a, ^@b, ^@@c, ^$d
## Captures
xs in [Integer => a, String]
xs => Integer => b, *rest
hash => {
a:,
b: Foo::Bar =>
# 0
# 1
baz, # 2
# 3
c: [d],
}
## Alternation patterns
v => a | b
v => a | b | c | d | e
# Prism's bug? This is a valid syntax but the patterns before the parentheses are ignored.
v => b | c | d
v => [a, :b] | c, d | [*, e, *] | { f: Integer | Nil, g:, ** } | ^(h.i(j)) | ^@k | [String] => l
v =>
# 0
# 1
a |
# 2
# 3
[b | c] |
# 4
# 5
{ d: } # 6
# 7
## Mixed with case-in
case foo.bar
in 1, 2, a, *rest
1
in [*, :a, a, *] | [:b, b, *]
2
in {
a: {
x: Integer => y,
b: {
c: [^d, e],
},
},
}
3
in ^(aa.bb(1).cc[2]&.dd) | nil | true | false
4
else
case bar.baz
in *a
5
else
6
end
end
case v
in [] | {}
nil
in [:a] if a
aa
in {
a: Integer,
b: String => s,
}
bb
in {
a: Integer,
b: { c: c, d: d, ** },
} if foo(v).bar?
cc
end