diff options
| -rw-r--r-- | doc/langref.html.in | 91 |
1 files changed, 88 insertions, 3 deletions
diff --git a/doc/langref.html.in b/doc/langref.html.in index ef914375f4..818e0b5fe4 100644 --- a/doc/langref.html.in +++ b/doc/langref.html.in @@ -2350,12 +2350,12 @@ fn doTheTest() void { var full = Full{ .number = 0x1234 }; var divided = @bitCast(Divided, full); switch (builtin.endian) { - builtin.Endian.Big => { + .Big => { assert(divided.half1 == 0x12); assert(divided.quarter3 == 0x3); assert(divided.quarter4 == 0x4); }, - builtin.Endian.Little => { + .Little => { assert(divided.half1 == 0x34); assert(divided.quarter3 == 0x2); assert(divided.quarter4 == 0x1); @@ -2630,6 +2630,8 @@ test "@tagName" { assert(mem.eql(u8, @tagName(Small.Three), "Three")); } {#code_end#} + {#see_also|@memberName|@memberCount|@tagName|@sizeOf#} + {#header_open|extern enum#} <p> By default, enums are not guaranteed to be compatible with the C ABI: @@ -2646,6 +2648,7 @@ const Foo = extern enum { A, B, C }; export fn entry(foo: Foo) void { } {#code_end#} {#header_close#} + {#header_open|packed enum#} <p>By default, the size of enums is not guaranteed.</p> <p>{#syntax#}packed enum{#endsyntax#} causes the size of the enum to be the same as the size of the @@ -2664,8 +2667,40 @@ test "packed enum" { {#code_end#} <p>This makes the enum eligible to be in a {#link|packed struct#}.</p> {#header_close#} - {#see_also|@memberName|@memberCount|@tagName|@sizeOf#} + + {#header_open|Enum Literals#} + <p> + Enum literals allow specifying the name of an enum field without specifying the enum type: + </p> + {#code_begin|test#} +const std = @import("std"); +const assert = std.debug.assert; + +const Color = enum { + Auto, + Off, + On, +}; + +test "enum literals" { + const color1: Color = .Auto; + const color2 = Color.Auto; + assert(color1 == color2); +} + +test "switch using enum literals" { + const color = Color.On; + const result = switch (color) { + .Auto => false, + .On => true, + .Off => false, + }; + assert(result); +} + {#code_end#} + {#header_close#} {#header_close#} + {#header_open|union#} <p> A bare {#syntax#}union{#endsyntax#} defines a set of possible types that a value @@ -3006,7 +3041,57 @@ test "switch on tagged union" { } {#code_end#} {#see_also|comptime|enum|@compileError|Compile Variables#} + + {#header_open|Exhaustive Switching#} + <p> + When a {#syntax#}switch{#endsyntax#} expression does not have an {#syntax#}else{#endsyntax#} clause, + it must exhaustively list all the possible values. Failure to do so is a compile error: + </p> + {#code_begin|test_err|not handled in switch#} +const Color = enum { + Auto, + Off, + On, +}; + +test "exhaustive switching" { + const color = Color.Off; + switch (color) { + Color.Auto => {}, + Color.On => {}, + } +} + {#code_end#} {#header_close#} + + {#header_open|Switching with Enum Literals#} + <p> + {#link|Enum Literals#} can be useful to use with {#syntax#}switch{#endsyntax#} to avoid + repetitively specifying {#link|enum#} or {#link|union#} types: + </p> + {#code_begin|test#} +const std = @import("std"); +const assert = std.debug.assert; + +const Color = enum { + Auto, + Off, + On, +}; + +test "enum literals with switch" { + const color = Color.Off; + const result = switch (color) { + .Auto => false, + .On => false, + .Off => true, + }; + assert(result); +} + {#code_end#} + {#header_close#} + {#header_close#} + {#header_open|while#} <p> A while loop is used to repeatedly execute an expression until |