value: add TryFrom implementations to get inner type from value

Cargo.toml

@@ -23,3 +23,4 @@ serde_derive = { version = "1.0.79", optional = true }
 
 [features]
 serde-1 = ["serde", "serde_bytes", "serde_derive", "indexmap/serde-1"]
+try_from = []

src/lib.rs

@@ -1,4 +1,5 @@
 #![cfg_attr(test, feature(test))]
+#![cfg_attr(feature = "try_from", feature(try_from))]
 
 extern crate byteorder;
 extern crate bytes;

src/value/mod.rs

@@ -1,3 +1,5 @@
+#[cfg(feature = "try_from")]
+use std::convert::TryFrom;
 use std::fmt;
 use std::net::Ipv4Addr;
 use std::str::FromStr;
@@ -412,6 +414,18 @@ macro_rules! construct_types {
           Value::$konst(value)
         }
       }
+
+      #[cfg(feature = "try_from")]
+      impl TryFrom<Value> for $($value_type)* {
+        type Error = KbinError;
+
+        fn try_from(value: Value) -> Result<Self, Self::Error> {
+          match value {
+            Value::$konst(v) => Ok(v),
+            value => Err(KbinErrorKind::ValueTypeMismatch(StandardType::$konst, value).into()),
+          }
+        }
+      }
     )+
 
     impl Value {