summaryrefslogtreecommitdiffstats
path: root/third_party/rust/toml/src/macros.rs
diff options
context:
space:
mode:
Diffstat (limited to 'third_party/rust/toml/src/macros.rs')
-rw-r--r--third_party/rust/toml/src/macros.rs459
1 files changed, 459 insertions, 0 deletions
diff --git a/third_party/rust/toml/src/macros.rs b/third_party/rust/toml/src/macros.rs
new file mode 100644
index 0000000000..19b2ce2286
--- /dev/null
+++ b/third_party/rust/toml/src/macros.rs
@@ -0,0 +1,459 @@
+pub use serde::de::{Deserialize, IntoDeserializer};
+
+use crate::value::{Array, Table, Value};
+
+/// Construct a [`toml::Value`] from TOML syntax.
+///
+/// [`toml::Value`]: value/enum.Value.html
+///
+/// ```rust
+/// let cargo_toml = toml::toml! {
+/// [package]
+/// name = "toml"
+/// version = "0.4.5"
+/// authors = ["Alex Crichton <alex@alexcrichton.com>"]
+///
+/// [badges]
+/// travis-ci = { repository = "alexcrichton/toml-rs" }
+///
+/// [dependencies]
+/// serde = "1.0"
+///
+/// [dev-dependencies]
+/// serde_derive = "1.0"
+/// serde_json = "1.0"
+/// };
+///
+/// println!("{:#?}", cargo_toml);
+/// ```
+#[macro_export]
+macro_rules! toml {
+ ($($toml:tt)+) => {{
+ let table = $crate::value::Table::new();
+ let mut root = $crate::Value::Table(table);
+ $crate::toml_internal!(@toplevel root [] $($toml)+);
+ root
+ }};
+}
+
+// TT-muncher to parse TOML syntax into a toml::Value.
+//
+// @toplevel -- Parse tokens outside of an inline table or inline array. In
+// this state, `[table headers]` and `[[array headers]]` are
+// allowed and `key = value` pairs are not separated by commas.
+//
+// @topleveldatetime -- Helper to parse a Datetime from string and insert it
+// into a table, continuing in the @toplevel state.
+//
+// @path -- Turn a path segment into a string. Segments that look like idents
+// are stringified, while quoted segments like `"cfg(windows)"`
+// are not.
+//
+// @value -- Parse the value part of a `key = value` pair, which may be a
+// primitive or inline table or inline array.
+//
+// @table -- Parse the contents of an inline table, returning them as a
+// toml::Value::Table.
+//
+// @tabledatetime -- Helper to parse a Datetime from string and insert it
+// into a table, continuing in the @table state.
+//
+// @array -- Parse the contents of an inline array, returning them as a
+// toml::Value::Array.
+//
+// @arraydatetime -- Helper to parse a Datetime from string and push it into
+// an array, continuing in the @array state.
+//
+// @trailingcomma -- Helper to append a comma to a sequence of tokens if the
+// sequence is non-empty and does not already end in a trailing
+// comma.
+//
+#[macro_export]
+#[doc(hidden)]
+macro_rules! toml_internal {
+ // Base case, no elements remaining.
+ (@toplevel $root:ident [$($path:tt)*]) => {};
+
+ // Parse negative number `key = -value`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = - $v:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@toplevel $root [$($path)*] $($($k)-+).+ = (-$v) $($rest)*);
+ };
+
+ // Parse positive number `key = +value`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = + $v:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@toplevel $root [$($path)*] $($($k)-+).+ = ($v) $($rest)*);
+ };
+
+ // Parse offset datetime `key = 1979-05-27T00:32:00.999999-07:00`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt . $frac:tt - $tzh:tt : $tzm:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec . $frac - $tzh : $tzm) $($rest)*);
+ };
+ // Space instead of T.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt . $frac:tt - $tzh:tt : $tzm:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec . $frac - $tzh : $tzm) $($rest)*);
+ };
+
+ // Parse offset datetime `key = 1979-05-27T00:32:00-07:00`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt - $tzh:tt : $tzm:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec - $tzh : $tzm) $($rest)*);
+ };
+ // Space instead of T.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt - $tzh:tt : $tzm:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec - $tzh : $tzm) $($rest)*);
+ };
+
+ // Parse local datetime `key = 1979-05-27T00:32:00.999999`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt . $frac:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec . $frac) $($rest)*);
+ };
+ // Space instead of T.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt . $frac:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec . $frac) $($rest)*);
+ };
+
+ // Parse offset datetime `key = 1979-05-27T07:32:00Z` and local datetime `key = 1979-05-27T07:32:00`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec) $($rest)*);
+ };
+ // Space instead of T.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec) $($rest)*);
+ };
+
+ // Parse local date `key = 1979-05-27`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($yr - $mo - $day) $($rest)*);
+ };
+
+ // Parse local time `key = 00:32:00.999999`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $hr:tt : $min:tt : $sec:tt . $frac:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($hr : $min : $sec . $frac) $($rest)*);
+ };
+
+ // Parse local time `key = 07:32:00`.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $hr:tt : $min:tt : $sec:tt $($rest:tt)*) => {
+ $crate::toml_internal!(@topleveldatetime $root [$($path)*] $($($k)-+).+ = ($hr : $min : $sec) $($rest)*);
+ };
+
+ // Parse any other `key = value` including string, inline array, inline
+ // table, number, and boolean.
+ (@toplevel $root:ident [$($path:tt)*] $($($k:tt)-+).+ = $v:tt $($rest:tt)*) => {{
+ $crate::macros::insert_toml(
+ &mut $root,
+ &[$($path)* $(&concat!($("-", $crate::toml_internal!(@path $k),)+)[1..], )+],
+ $crate::toml_internal!(@value $v));
+ $crate::toml_internal!(@toplevel $root [$($path)*] $($rest)*);
+ }};
+
+ // Parse array header `[[bin]]`.
+ (@toplevel $root:ident $oldpath:tt [[$($($path:tt)-+).+]] $($rest:tt)*) => {
+ $crate::macros::push_toml(
+ &mut $root,
+ &[$(&concat!($("-", $crate::toml_internal!(@path $path),)+)[1..],)+]);
+ $crate::toml_internal!(@toplevel $root [$(&concat!($("-", $crate::toml_internal!(@path $path),)+)[1..],)+] $($rest)*);
+ };
+
+ // Parse table header `[patch.crates-io]`.
+ (@toplevel $root:ident $oldpath:tt [$($($path:tt)-+).+] $($rest:tt)*) => {
+ $crate::macros::insert_toml(
+ &mut $root,
+ &[$(&concat!($("-", $crate::toml_internal!(@path $path),)+)[1..],)+],
+ $crate::Value::Table($crate::value::Table::new()));
+ $crate::toml_internal!(@toplevel $root [$(&concat!($("-", $crate::toml_internal!(@path $path),)+)[1..],)+] $($rest)*);
+ };
+
+ // Parse datetime from string and insert into table.
+ (@topleveldatetime $root:ident [$($path:tt)*] $($($k:tt)-+).+ = ($($datetime:tt)+) $($rest:tt)*) => {
+ $crate::macros::insert_toml(
+ &mut $root,
+ &[$($path)* $(&concat!($("-", $crate::toml_internal!(@path $k),)+)[1..], )+],
+ $crate::Value::Datetime(concat!($(stringify!($datetime)),+).parse().unwrap()));
+ $crate::toml_internal!(@toplevel $root [$($path)*] $($rest)*);
+ };
+
+ // Turn a path segment into a string.
+ (@path $ident:ident) => {
+ stringify!($ident)
+ };
+
+ // For a path segment that is not an ident, expect that it is already a
+ // quoted string, like in `[target."cfg(windows)".dependencies]`.
+ (@path $quoted:tt) => {
+ $quoted
+ };
+
+ // Construct a Value from an inline table.
+ (@value { $($inline:tt)* }) => {{
+ let mut table = $crate::Value::Table($crate::value::Table::new());
+ $crate::toml_internal!(@trailingcomma (@table table) $($inline)*);
+ table
+ }};
+
+ // Construct a Value from an inline array.
+ (@value [ $($inline:tt)* ]) => {{
+ let mut array = $crate::value::Array::new();
+ $crate::toml_internal!(@trailingcomma (@array array) $($inline)*);
+ $crate::Value::Array(array)
+ }};
+
+ (@value (-nan)) => {
+ $crate::Value::Float(-::std::f64::NAN)
+ };
+
+ (@value (nan)) => {
+ $crate::Value::Float(::std::f64::NAN)
+ };
+
+ (@value nan) => {
+ $crate::Value::Float(::std::f64::NAN)
+ };
+
+ (@value (-inf)) => {
+ $crate::Value::Float(::std::f64::NEG_INFINITY)
+ };
+
+ (@value (inf)) => {
+ $crate::Value::Float(::std::f64::INFINITY)
+ };
+
+ (@value inf) => {
+ $crate::Value::Float(::std::f64::INFINITY)
+ };
+
+ // Construct a Value from any other type, probably string or boolean or number.
+ (@value $v:tt) => {{
+ // TODO: Implement this with something like serde_json::to_value instead.
+ let de = $crate::macros::IntoDeserializer::<$crate::de::Error>::into_deserializer($v);
+ <$crate::Value as $crate::macros::Deserialize>::deserialize(de).unwrap()
+ }};
+
+ // Base case of inline table.
+ (@table $root:ident) => {};
+
+ // Parse negative number `key = -value`.
+ (@table $root:ident $($($k:tt)-+).+ = - $v:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@table $root $($($k)-+).+ = (-$v) , $($rest)*);
+ };
+
+ // Parse positive number `key = +value`.
+ (@table $root:ident $($($k:tt)-+).+ = + $v:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@table $root $($($k)-+).+ = ($v) , $($rest)*);
+ };
+
+ // Parse offset datetime `key = 1979-05-27T00:32:00.999999-07:00`.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt . $frac:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec . $frac - $tzh : $tzm) $($rest)*);
+ };
+ // Space instead of T.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt . $frac:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec . $frac - $tzh : $tzm) $($rest)*);
+ };
+
+ // Parse offset datetime `key = 1979-05-27T00:32:00-07:00`.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec - $tzh : $tzm) $($rest)*);
+ };
+ // Space instead of T.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec - $tzh : $tzm) $($rest)*);
+ };
+
+ // Parse local datetime `key = 1979-05-27T00:32:00.999999`.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt . $frac:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec . $frac) $($rest)*);
+ };
+ // Space instead of T.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt . $frac:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec . $frac) $($rest)*);
+ };
+
+ // Parse offset datetime `key = 1979-05-27T07:32:00Z` and local datetime `key = 1979-05-27T07:32:00`.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $dhr : $min : $sec) $($rest)*);
+ };
+ // Space instead of T.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $day T $hr : $min : $sec) $($rest)*);
+ };
+
+ // Parse local date `key = 1979-05-27`.
+ (@table $root:ident $($($k:tt)-+).+ = $yr:tt - $mo:tt - $day:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($yr - $mo - $day) $($rest)*);
+ };
+
+ // Parse local time `key = 00:32:00.999999`.
+ (@table $root:ident $($($k:tt)-+).+ = $hr:tt : $min:tt : $sec:tt . $frac:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($hr : $min : $sec . $frac) $($rest)*);
+ };
+
+ // Parse local time `key = 07:32:00`.
+ (@table $root:ident $($($k:tt)-+).+ = $hr:tt : $min:tt : $sec:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@tabledatetime $root $($($k)-+).+ = ($hr : $min : $sec) $($rest)*);
+ };
+
+ // Parse any other type, probably string or boolean or number.
+ (@table $root:ident $($($k:tt)-+).+ = $v:tt , $($rest:tt)*) => {
+ $crate::macros::insert_toml(
+ &mut $root,
+ &[$(&concat!($("-", $crate::toml_internal!(@path $k),)+)[1..], )+],
+ $crate::toml_internal!(@value $v));
+ $crate::toml_internal!(@table $root $($rest)*);
+ };
+
+ // Parse a Datetime from string and continue in @table state.
+ (@tabledatetime $root:ident $($($k:tt)-+).+ = ($($datetime:tt)*) $($rest:tt)*) => {
+ $crate::macros::insert_toml(
+ &mut $root,
+ &[$(&concat!($("-", $crate::toml_internal!(@path $k),)+)[1..], )+],
+ $crate::Value::Datetime(concat!($(stringify!($datetime)),+).parse().unwrap()));
+ $crate::toml_internal!(@table $root $($rest)*);
+ };
+
+ // Base case of inline array.
+ (@array $root:ident) => {};
+
+ // Parse negative number `-value`.
+ (@array $root:ident - $v:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@array $root (-$v) , $($rest)*);
+ };
+
+ // Parse positive number `+value`.
+ (@array $root:ident + $v:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@array $root ($v) , $($rest)*);
+ };
+
+ // Parse offset datetime `1979-05-27T00:32:00.999999-07:00`.
+ (@array $root:ident $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt . $frac:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $dhr : $min : $sec . $frac - $tzh : $tzm) $($rest)*);
+ };
+ // Space instead of T.
+ (@array $root:ident $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt . $frac:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $day T $hr : $min : $sec . $frac - $tzh : $tzm) $($rest)*);
+ };
+
+ // Parse offset datetime `1979-05-27T00:32:00-07:00`.
+ (@array $root:ident $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $dhr : $min : $sec - $tzh : $tzm) $($rest)*);
+ };
+ // Space instead of T.
+ (@array $root:ident $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt - $tzh:tt : $tzm:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $day T $hr : $min : $sec - $tzh : $tzm) $($rest)*);
+ };
+
+ // Parse local datetime `1979-05-27T00:32:00.999999`.
+ (@array $root:ident $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt . $frac:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $dhr : $min : $sec . $frac) $($rest)*);
+ };
+ // Space instead of T.
+ (@array $root:ident $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt . $frac:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $day T $hr : $min : $sec . $frac) $($rest)*);
+ };
+
+ // Parse offset datetime `1979-05-27T07:32:00Z` and local datetime `1979-05-27T07:32:00`.
+ (@array $root:ident $yr:tt - $mo:tt - $dhr:tt : $min:tt : $sec:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $dhr : $min : $sec) $($rest)*);
+ };
+ // Space instead of T.
+ (@array $root:ident $yr:tt - $mo:tt - $day:tt $hr:tt : $min:tt : $sec:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $day T $hr : $min : $sec) $($rest)*);
+ };
+
+ // Parse local date `1979-05-27`.
+ (@array $root:ident $yr:tt - $mo:tt - $day:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($yr - $mo - $day) $($rest)*);
+ };
+
+ // Parse local time `00:32:00.999999`.
+ (@array $root:ident $hr:tt : $min:tt : $sec:tt . $frac:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($hr : $min : $sec . $frac) $($rest)*);
+ };
+
+ // Parse local time `07:32:00`.
+ (@array $root:ident $hr:tt : $min:tt : $sec:tt , $($rest:tt)*) => {
+ $crate::toml_internal!(@arraydatetime $root ($hr : $min : $sec) $($rest)*);
+ };
+
+ // Parse any other type, probably string or boolean or number.
+ (@array $root:ident $v:tt , $($rest:tt)*) => {
+ $root.push($crate::toml_internal!(@value $v));
+ $crate::toml_internal!(@array $root $($rest)*);
+ };
+
+ // Parse a Datetime from string and continue in @array state.
+ (@arraydatetime $root:ident ($($datetime:tt)*) $($rest:tt)*) => {
+ $root.push($crate::Value::Datetime(concat!($(stringify!($datetime)),+).parse().unwrap()));
+ $crate::toml_internal!(@array $root $($rest)*);
+ };
+
+ // No trailing comma required if the tokens are empty.
+ (@trailingcomma ($($args:tt)*)) => {
+ $crate::toml_internal!($($args)*);
+ };
+
+ // Tokens end with a trailing comma, do not append another one.
+ (@trailingcomma ($($args:tt)*) ,) => {
+ $crate::toml_internal!($($args)* ,);
+ };
+
+ // Tokens end with something other than comma, append a trailing comma.
+ (@trailingcomma ($($args:tt)*) $last:tt) => {
+ $crate::toml_internal!($($args)* $last ,);
+ };
+
+ // Not yet at the last token.
+ (@trailingcomma ($($args:tt)*) $first:tt $($rest:tt)+) => {
+ $crate::toml_internal!(@trailingcomma ($($args)* $first) $($rest)+);
+ };
+}
+
+// Called when parsing a `key = value` pair.
+// Inserts an entry into the table at the given path.
+pub fn insert_toml(root: &mut Value, path: &[&str], value: Value) {
+ *traverse(root, path) = value;
+}
+
+// Called when parsing an `[[array header]]`.
+// Pushes an empty table onto the array at the given path.
+pub fn push_toml(root: &mut Value, path: &[&str]) {
+ let target = traverse(root, path);
+ if !target.is_array() {
+ *target = Value::Array(Array::new());
+ }
+ target
+ .as_array_mut()
+ .unwrap()
+ .push(Value::Table(Table::new()));
+}
+
+fn traverse<'a>(root: &'a mut Value, path: &[&str]) -> &'a mut Value {
+ let mut cur = root;
+ for &key in path {
+ // Lexical lifetimes :D
+ let cur1 = cur;
+
+ // From the TOML spec:
+ //
+ // > Each double-bracketed sub-table will belong to the most recently
+ // > defined table element above it.
+ let cur2 = if cur1.is_array() {
+ cur1.as_array_mut().unwrap().last_mut().unwrap()
+ } else {
+ cur1
+ };
+
+ // We are about to index into this value, so it better be a table.
+ if !cur2.is_table() {
+ *cur2 = Value::Table(Table::new());
+ }
+
+ if !cur2.as_table().unwrap().contains_key(key) {
+ // Insert an empty table for the next loop iteration to point to.
+ let empty = Value::Table(Table::new());
+ cur2.as_table_mut().unwrap().insert(key.to_owned(), empty);
+ }
+
+ // Step into the current table.
+ cur = cur2.as_table_mut().unwrap().get_mut(key).unwrap();
+ }
+ cur
+}