1 files changed, 23 insertions, 5 deletions
diff --git a/src/package/version.rs b/src/package/version.rs
index c27bf92..359c80f 100644
--- a/src/package/version.rs
+++ b/src/package/version.rs
@@ -10,6 +10,7 @@
 
 use std::ops::Deref;
 
+use anyhow::Context;
 use anyhow::Error;
 use anyhow::Result;
 use pom::parser::Parser as PomParser;
@@ -25,11 +26,7 @@ pub struct PackageVersionConstraint {
 }
 
 impl PackageVersionConstraint {
-    pub fn new(s: String) -> Result<Self> {
-        Self::parser().parse(s.as_bytes()).map_err(Error::from)
-    }
-
-    pub fn parser<'a>() -> PomParser<'a, u8, Self> {
+    fn parser<'a>() -> PomParser<'a, u8, Self> {
         (pom::parser::sym(b'=') + PackageVersion::parser())
             .convert(|(constraint, version)| {
                 String::from_utf8(vec![constraint]).map(|c| (c, version))
@@ -53,6 +50,27 @@ impl PackageVersionConstraint {
     }
 }
 
+impl std::convert::TryFrom<String> for PackageVersionConstraint {
+    type Error = anyhow::Error;
+
+    fn try_from(s: String) -> Result<Self> {
+        Self::try_from(&s as &str)
+    }
+}
+
+impl std::convert::TryFrom<&str> for PackageVersionConstraint {
+    type Error = anyhow::Error;
+
+    fn try_from(s: &str) -> Result<Self> {
+        PackageVersionConstraint::parser()
+            .parse(s.as_bytes())
+            .context("Failed to parse package version constraint")
+            .context("A package version constraint must have a comparator and a version string, like so: =0.1.0")
+            .map_err(Error::from)
+
+    }
+}
+
 #[derive(
     parse_display::Display,
     Serialize,