Added pickling support to lexicons

Author: MichaelGoodale

python/tests/test_mg.py

@@ -1,4 +1,5 @@
 import pytest
+import pickle
 
 from python_mg import Lexicon, Continuation
 
@@ -13,6 +14,12 @@ def test_lexicon():
     )
 
 
+def test_pickling():
+    x = Lexicon("a::b= a\nb::b")
+    x_pickle = pickle.dumps(x)
+    assert pickle.loads(x_pickle) == x
+
+
 def test_memory_load():
     grammar = Lexicon("a::b= c= +a +e C\nb::b -a\nc::c -e")
     parse = grammar.parse("c b a", "C")[0]

src/lib.rs

@@ -117,7 +117,7 @@ impl PySyntacticStructure {
     }
 }
 
-#[pyclass(name = "Lexicon", str, eq, frozen)]
+#[pyclass(name = "Lexicon", str, eq, frozen, module = "python_mg")]
 #[derive(Debug, Clone, Eq, PartialEq)]
 struct PyLexicon {
     lexicon: Lexicon<String, String>,
@@ -332,6 +332,10 @@ impl PyLexicon {
 
 #[pymethods]
 impl PyLexicon {
+    fn __getnewargs__(&self) -> (String,) {
+        (self.lexicon.to_string(),)
+    }
+
     fn mdl(&self, n_phonemes: u16) -> PyResult<f64> {
         Ok(self.lexicon.mdl_score(n_phonemes).map_err(|e| anyhow!(e))?)
     }