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Merge pull request 'docs: langref: Clear up terminology used for top-level doc comments' (#31920) into master
Reviewed-on: https://codeberg.org/ziglang/zig/pulls/31920 Reviewed-by: Andrew Kelley <andrew@ziglang.org>
This commit is contained in:
Andrew Kelley
+49
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@@ -388,22 +388,15 @@
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</p>
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{#see_also|Values|Tuples|@import|Errors|Entry Point|Source Encoding|try#}
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{#header_close#}
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{#header_open|Comments#}
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<p>
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Zig supports 3 types of comments. Normal comments are ignored, but doc comments
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and top-level doc comments are used by the compiler to generate the package documentation.
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</p>
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<p>
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The generated documentation is still experimental, and can be produced with:
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</p>
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{#shell_samp#}zig test -femit-docs main.zig{#end_shell_samp#}
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<p>There are three types of comments. Normal comments are ignored, while {#link|Doc Comments#}
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and {#link|Top-Level Doc Comments#} are used by the compiler to generate
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the package documentation.</p>
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{#code|comments.zig#}
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<p>
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There are no multiline comments in Zig (e.g. like <code class="c">/* */</code>
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comments in C). This allows Zig to have the property that each line
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of code can be tokenized out of context.
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</p>
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<p>There are no multiline comments. Zig has the property that each line
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of code can be tokenized independently.</p>
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{#header_open|Doc Comments#}
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<p>
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A doc comment is one that begins with exactly three slashes (i.e.
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@@ -429,17 +422,28 @@
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{#header_open|Top-Level Doc Comments#}
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<p>
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A top-level doc comment is one that begins with two slashes and an exclamation
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point: {#syntax#}//!{#endsyntax#}; it documents the current module.
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point: {#syntax#}//!{#endsyntax#}; it documents the type which owns the containing
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{#link|Namespace#}.
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</p>
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<p>
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It is a compile error if a top-level doc comment is not placed at the start
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of a {#link|container|Containers#}, before any expressions.
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of a namespace, before any expressions.
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</p>
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{#code|tldoc_comments.zig#}
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{#header_close#}
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{#header_close#}
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{#header_open|Namespace#}
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<p>A namespace in Zig is created by {#link|struct#}, {#link|enum#}, {#link|union#}, and {#link|opaque#}.</p>
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<p>They contain {#link|Namespace Level Variables#},
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{#link|function|Functions#} declarations, and {#link|comptime#} blocks.</p>
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<p>Although namespaces use curly braces to surround their definition,
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they should not be confused with {#link|blocks|Blocks#} or function bodies.</p>
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<p><strong>Every Zig source file is implicitly a struct</strong>, with the keyword
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{#syntax#}struct{#endsyntax#} and curly braces omitted.</p>
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{#header_close#}
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{#header_open|Identifiers#}
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<p>
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Identifiers must start with an alphabetic character or underscore and may be followed
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@@ -813,7 +817,7 @@
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{#code|destructuring_to_existing.zig#}
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<p>
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A destructuring expression may only appear within a block (i.e. not at container scope).
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A destructuring expression may only appear within a block (i.e. not at {#link|Namespace#} scope).
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The left hand side of the assignment must consist of a comma separated list,
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each element of which may be either an lvalue (for instance, an existing `var`) or a variable declaration:
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</p>
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@@ -993,27 +997,23 @@
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</p>
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{#see_also|Exporting a C Library#}
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{#header_open|Container Level Variables#}
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<p>
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{#link|Container|Containers#} level variables have static lifetime and are order-independent and lazily analyzed.
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The initialization value of container level variables is implicitly
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{#link|comptime#}. If a container level variable is {#syntax#}const{#endsyntax#} then its value is
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{#syntax#}comptime{#endsyntax#}-known, otherwise it is runtime-known.
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</p>
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{#code|test_container_level_variables.zig#}
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<p>
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Container level variables may be declared inside a {#link|struct#}, {#link|union#}, {#link|enum#}, or {#link|opaque#}:
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</p>
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{#code|test_namespaced_container_level_variable.zig#}
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{#header_open|Namespace Level Variables#}
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<p>{#link|Namespace|Namespace#} level variables have global lifetime and are
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order-independent and lazily analyzed. The initialization value of
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namespace level variables is implicitly {#link|comptime#}. If a namespace
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level variable is {#syntax#}const{#endsyntax#} then its value is
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{#syntax#}comptime{#endsyntax#}-known, otherwise it is runtime-known.</p>
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{#code|test_namespace_level_variables.zig#}
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<p>Namespace level variables may be declared inside a {#link|struct#},
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{#link|union#}, {#link|enum#}, or {#link|opaque#}:</p>
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{#code|test_namespaced_variable.zig#}
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{#header_close#}
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{#header_open|Static Local Variables#}
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<p>
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It is also possible to have local variables with static lifetime by using containers inside functions.
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</p>
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{#code|test_static_local_variable.zig#}
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{#header_open|Locally-Scoped Global Variables#}
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<p>It is also possible to have local variables with global lifetime by
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using {#link|namespaces|Namespace#} inside functions.</p>
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{#code|test_locally_scoped_global_variable.zig#}
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{#header_close#}
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@@ -1022,10 +1022,8 @@
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{#syntax#}threadlocal{#endsyntax#} keyword,
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which makes each thread work with a separate instance of the variable:</p>
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{#code|test_thread_local_variables.zig#}
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<p>
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For {#link|Single Threaded Builds#}, all thread local variables are treated as regular {#link|Container Level Variables#}.
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</p>
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<p>For {#link|Single Threaded Builds#}, all thread local variables are
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treated as regular {#link|Namespace Level Variables#}.</p>
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<p>
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Thread local variables may not be {#syntax#}const{#endsyntax#}.
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</p>
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@@ -4123,13 +4121,11 @@ fn performFn(start_value: i32) i32 {
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</p>
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{#code|test_fibonacci_comptime_unreachable.zig#}
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<p>
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At {#link|container|Containers#} level (outside of any function), all expressions are implicitly
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{#syntax#}comptime{#endsyntax#} expressions. This means that we can use functions to
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initialize complex static data. For example:
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</p>
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{#code|test_container-level_comptime_expressions.zig#}
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<p>At {#link|Namespace#} level (outside of any function), all expressions
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are implicitly {#syntax#}comptime{#endsyntax#} expressions. This means
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that we can use functions to initialize complex constant data. For
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example:</p>
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{#code|test_namespace-level_comptime_expressions.zig#}
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<p>
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When we compile this program, Zig generates the constants
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@@ -4309,7 +4305,7 @@ pub fn print(self: *Writer, arg0: []const u8, arg1: i32) !void {
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{#header_open|Global Assembly#}
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<p>
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When an assembly expression occurs in a {#link|container|Containers#} level {#link|comptime#} block, this is
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When an assembly expression occurs in a {#link|Namespace#} level {#link|comptime#} block, this is
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<strong>global assembly</strong>.
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</p>
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<p>
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@@ -4946,25 +4942,18 @@ fn cmpxchgWeakButNotAtomic(comptime T: type, ptr: *T, expected_value: T, new_val
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{#header_close#}
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{#header_open|@hasDecl#}
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<pre>{#syntax#}@hasDecl(comptime Container: type, comptime name: []const u8) bool{#endsyntax#}</pre>
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<p>
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Returns whether or not a {#link|container|Containers#} has a declaration
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matching {#syntax#}name{#endsyntax#}.
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</p>
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<pre>{#syntax#}@hasDecl(comptime Namespace: type, comptime name: []const u8) bool{#endsyntax#}</pre>
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<p>Returns whether or not a {#link|Namespace#} has a declaration matching {#syntax#}name{#endsyntax#}.</p>
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{#code|test_hasDecl_builtin.zig#}
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{#see_also|@hasField#}
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{#header_close#}
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{#header_open|@hasField#}
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<pre>{#syntax#}@hasField(comptime Container: type, comptime name: []const u8) bool{#endsyntax#}</pre>
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<pre>{#syntax#}@hasField(comptime T: type, comptime name: []const u8) bool{#endsyntax#}</pre>
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<p>Returns whether the field name of a struct, union, or enum exists.</p>
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<p>
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The result is a compile time constant.
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</p>
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<p>
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It does not include functions, variables, or constants.
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</p>
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<p>The result is a compile time constant.</p>
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<p>It does not include functions, variables, or constants.</p>
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{#see_also|@hasDecl#}
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{#header_close#}
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@@ -5980,7 +5969,7 @@ fn cmpxchgWeakButNotAtomic(comptime T: type, ptr: *T, expected_value: T, new_val
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{#header_open|Single Threaded Builds#}
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<p>Zig has a compile option <kbd>-fsingle-threaded</kbd> which has the following effects:</p>
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<ul>
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<li>All {#link|Thread Local Variables#} are treated as regular {#link|Container Level Variables#}.</li>
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<li>All {#link|Thread Local Variables#} are treated as regular {#link|Namespace Level Variables#}.</li>
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<li>The overhead of {#link|Async Functions#} becomes equivalent to function call overhead.</li>
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<li>The {#syntax#}@import("builtin").single_threaded{#endsyntax#} becomes {#syntax#}true{#endsyntax#}
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and therefore various userland APIs which read this variable become more efficient.
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@@ -6635,7 +6624,7 @@ const builtin = @import("builtin");
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{#header_open|Panic Handler#}
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<p>
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The Zig Standard Library looks for a declaration named {#syntax#}panic{#endsyntax#} in the root module's
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root source file. If present, it is expected to be a namespace (container type) with declarations
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root source file. If present, it is expected to be a {#link|Namespace#} with declarations
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providing different panic handlers.
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</p>
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<p>
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@@ -7755,18 +7744,6 @@ fn readU32Be() u32 {}
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{#header_close#}
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{#header_open|Appendix#}
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{#header_open|Containers#}
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<p>
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A <em>container</em> in Zig is any syntactical construct that acts as a namespace to hold {#link|variable|Container Level Variables#} and {#link|function|Functions#} declarations.
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Containers are also type definitions which can be instantiated.
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{#link|Structs|struct#}, {#link|enums|enum#}, {#link|unions|union#}, {#link|opaques|opaque#}, and even Zig source files themselves are containers.
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</p>
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<p>
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Although containers (except Zig source files) use curly braces to surround their definition, they should not be confused with {#link|blocks|Blocks#} or functions.
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Containers do not contain statements.
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</p>
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{#header_close#}
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{#header_open|Grammar#}
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{#syntax_block|peg|grammar.peg#}
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Root <- skip ContainerMembers eof
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@@ -1,11 +1,10 @@
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//! This module provides functions for retrieving the current date and
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//! time with varying degrees of precision and accuracy. It does not
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//! depend on libc, but will use functions from it if available.
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//! Provides functions for retrieving the current date and time with varying
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//! degrees of precision and accuracy.
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const S = struct {
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//! Top level comments are allowed inside a container other than a module,
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//! but it is not very useful. Currently, when producing the package
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//! documentation, these comments are ignored.
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//! Top level comments are allowed inside namespaces other than the
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//! implicit struct created by files, but it is not very useful. Currently,
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//! when producing the package documentation, these comments are ignored.
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};
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// syntax
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