From ebe8923e72b9ff4997aef22bc27b169aa66c34c9 Mon Sep 17 00:00:00 2001
From: Ruud van Asseldonk <dev@veniogames.com>
Date: Sat, 24 Aug 2024 12:54:05 +0200
Subject: [PATCH] Implement float conversion for Python

---
 pyrcl/src/lib.rs | 2 +-
 pyrcl/test.py    | 2 ++
 src/decimal.rs   | 7 +++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/pyrcl/src/lib.rs b/pyrcl/src/lib.rs
index 0376f72a..05d3356b 100644
--- a/pyrcl/src/lib.rs
+++ b/pyrcl/src/lib.rs
@@ -34,7 +34,7 @@ fn build_python_value(py: Python, v: &Value) -> PyResult<PyObject> {
         Value::Null => PyNone::get(py).into(),
         Value::Bool(b) => b.to_object(py),
         Value::Int(i) => i.to_object(py),
-        Value::Decimal(_) => unimplemented!("TODO: Convert to Python float."),
+        Value::Decimal(d) => d.to_f64().to_object(py),
         Value::String(s) => s.to_object(py),
         Value::List(xs) => {
             let values = xs
diff --git a/pyrcl/test.py b/pyrcl/test.py
index 111dfc2e..43812b5b 100644
--- a/pyrcl/test.py
+++ b/pyrcl/test.py
@@ -18,6 +18,8 @@
 assert rcl.loads('["foobar"]') == ["foobar"]
 assert rcl.loads("{1, 2, 3}") == {1, 2, 3}
 assert rcl.loads('{1: "one", "two": 2}') == {1: "one", "two": 2}
+assert rcl.loads("1.0") == 1.0
+assert rcl.loads("0.25e-10") == 0.25e-10
 
 # Test that loading files works. This needs to be executed from this directory.
 assert rcl.load_file("test.rcl") == {
diff --git a/src/decimal.rs b/src/decimal.rs
index 9eac0368..74a34eb3 100644
--- a/src/decimal.rs
+++ b/src/decimal.rs
@@ -224,6 +224,13 @@ impl Decimal {
         };
         Some(result)
     }
+
+    /// Convert to a float. For many decimals this will be a lossy operation.
+    pub fn to_f64(&self) -> f64 {
+        let n = self.numer as f64;
+        let exp = 10.0_f64.powi(self.exponent as i32);
+        n * exp
+    }
 }
 
 impl PartialEq for Decimal {