bendns' repos / treaty
Diffstat (limited to 'src/walk/walkers/core/value.rs')
-rw-r--r--src/walk/walkers/core/value.rs89
1 files changed, 89 insertions, 0 deletions
diff --git a/src/walk/walkers/core/value.rs b/src/walk/walkers/core/value.rs
new file mode 100644
index 0000000..4f75750
--- /dev/null
+++ b/src/walk/walkers/core/value.rs
@@ -0,0 +1,89 @@
+use crate::{
+ any::static_wrapper::{BorrowedStatic, OwnedStatic},
+ effect::{Effect, Future},
+ never::Never,
+ protocol::{visitor::value::visit_value, Visitor},
+ WalkerTypes,
+};
+
+/// A very basic walker that uses the [`Value`][crate::protocol::visitor::value::Value] protocol.
+///
+/// Primitive types use this walker as their main walker.
+/// This walker doesn't consider it an error if the visitor doesn't have the protocol.
+pub struct ValueWalker<T>(T);
+
+impl<T> ValueWalker<T> {
+ /// Create walker from a value.
+ pub fn new(value: T) -> Self {
+ Self(value)
+ }
+}
+
+impl<T> From<T> for ValueWalker<T> {
+ fn from(value: T) -> Self {
+ Self::new(value)
+ }
+}
+
+impl<T: Copy> From<&T> for ValueWalker<T> {
+ fn from(value: &T) -> Self {
+ Self::new(*value)
+ }
+}
+
+impl<T> WalkerTypes for ValueWalker<T> {
+ type Error = Never;
+
+ type Output = ();
+}
+
+impl<'ctx, T: Send + 'static, E: Effect<'ctx>> crate::Walker<'ctx, E> for ValueWalker<T> {
+ fn walk<'a>(
+ self,
+ visitor: Visitor<'a, 'ctx>,
+ ) -> Future<'a, 'ctx, Result<Self::Output, Self::Error>, E>
+ where
+ Self: 'a,
+ {
+ // Attempt to visit using the value protocol.
+ E::map(
+ visit_value::<_, E>(visitor, OwnedStatic(self.0)),
+ |_| Ok(()),
+ )
+ }
+}
+
+/// Borrowed form of [`ValueWalker`].
+///
+/// This walker supports values borrowed for `'ctx` or longer.
+pub struct BorrowWalker<'ctx, T: ?Sized>(&'ctx T);
+
+impl<'ctx, T: ?Sized> BorrowWalker<'ctx, T> {
+ /// Create walker from a value.
+ pub fn new(value: &'ctx T) -> Self {
+ Self(value)
+ }
+}
+
+impl<'ctx, T: ?Sized> WalkerTypes for BorrowWalker<'ctx, T> {
+ type Error = Never;
+
+ type Output = ();
+}
+
+impl<'ctx, T: ?Sized + Sync + 'static, E: Effect<'ctx>> crate::Walker<'ctx, E>
+ for BorrowWalker<'ctx, T>
+{
+ fn walk<'a>(
+ self,
+ visitor: Visitor<'a, 'ctx>,
+ ) -> Future<'a, 'ctx, Result<Self::Output, Self::Error>, E>
+ where
+ Self: 'a,
+ {
+ // Attempt to visit using the value protocol.
+ E::map(visit_value::<_, E>(visitor, BorrowedStatic(self.0)), |_| {
+ Ok(())
+ })
+ }
+}