jani: add Display impls

jani/src/exprs.rs

@@ -1,5 +1,7 @@
 //! Expressions in JANI.
 
+use std::fmt::Display;
+
 use serde::{Deserialize, Serialize};
 
 use crate::Identifier;
@@ -18,6 +20,15 @@ pub enum MathConstant {
     Pi,
 }
 
+impl Display for MathConstant {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            MathConstant::EulersNumber => write!(f, "e"),
+            MathConstant::Pi => write!(f, "π"),
+        }
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone)]
 #[serde(untagged)]
 pub enum ConstantValue {
@@ -36,6 +47,16 @@ impl ConstantValue {
     }
 }
 
+impl Display for ConstantValue {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ConstantValue::Number(n) => write!(f, "{}", n),
+            ConstantValue::Boolean(b) => write!(f, "{}", b),
+            ConstantValue::MathConstant(c) => write!(f, "{}", c),
+        }
+    }
+}
+
 /// If-then-else: computes if `if` then `left` else `right`.
 ///
 /// The result type is the type of `left` if that is assignable from the type of

jani/src/lib.rs

@@ -10,7 +10,7 @@ pub mod models;
 pub mod properties;
 pub mod types;
 
-use std::io::Read;
+use std::{fmt::Display, io::Read};
 
 use models::Model;
 use serde::{Deserialize, Serialize};
@@ -21,6 +21,12 @@ use serde::{Deserialize, Serialize};
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Identifier(pub String);
 
+impl Display for Identifier {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
 /// Parse a JANI model from a `&str`.
 pub fn from_str(s: &str) -> serde_json::Result<Model> {
     serde_json::from_str(s)