Create an ident::AsVersion trait

This is useful for code that is generic over Ident to be able to require
that the Ident can represent itself as a VersionIdent.

Signed-off-by: J Robert Ray <jrray@imageworks.com>

crates/spk-schema/crates/ident/src/ident.rs

@@ -7,6 +7,8 @@ use std::str::FromStr;
 
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
+use crate::VersionIdent;
+
 #[cfg(test)]
 #[path = "./ident_test.rs"]
 mod ident_test;
@@ -201,3 +203,16 @@ where
         deserializer.deserialize_str(IdentVisitor(PhantomData))
     }
 }
+
+/// Idents that can be turned into a [`VersionIdent`] can implement this trait.
+pub trait AsVersion {
+    /// Return a borrowed version of this ident converted into a
+    /// [`VersionIdent`].
+    fn as_version(&self) -> &VersionIdent;
+}
+
+impl<T> AsVersion for Ident<VersionIdent, T> {
+    fn as_version(&self) -> &VersionIdent {
+        self.base().as_version()
+    }
+}

crates/spk-schema/crates/ident/src/ident_version.rs

@@ -11,7 +11,7 @@ use spk_schema_foundation::ident_ops::{TagPath, TagPathStrategy};
 use spk_schema_foundation::name::{PkgName, PkgNameBuf};
 use spk_schema_foundation::version::Version;
 
-use crate::{parsing, AnyIdent, BuildIdent, Ident, Result, ToAnyWithoutBuild};
+use crate::{parsing, AnyIdent, AsVersion, BuildIdent, Ident, Result, ToAnyWithoutBuild};
 
 /// Identifies a package name and number version.
 pub type VersionIdent = Ident<PkgNameBuf, Version>;
@@ -58,6 +58,12 @@ impl VersionIdent {
     }
 }
 
+impl AsVersion for VersionIdent {
+    fn as_version(&self) -> &VersionIdent {
+        self
+    }
+}
+
 macro_rules! version_ident_methods {
     ($Ident:ty $(, .$($access:ident).+)?) => {
         impl $Ident {

crates/spk-schema/crates/ident/src/lib.rs

@@ -15,7 +15,7 @@ mod request;
 mod satisfy;
 
 pub use error::{Error, Result};
-pub use ident::Ident;
+pub use ident::{AsVersion, Ident};
 pub use ident_any::{parse_ident, AnyIdent, ToAnyWithoutBuild};
 pub use ident_build::{parse_build_ident, BuildIdent};
 pub use ident_located::{LocatedBuildIdent, LocatedVersionIdent};