return JSON

.vim/coc-settings.json

@@ -0,0 +1,3 @@
+{
+	"rust-analyzer.cargo.features": ["python-module"]
+}

src/python.rs

@@ -1,6 +1,11 @@
 use std::io::Cursor;
 
-use crate::{error::Error, eval::cache::CBNCache, program::Program};
+use crate::{
+    error::{Error, SerializationError},
+    eval::cache::CBNCache,
+    program::Program,
+    serialize,
+};
 
 use pyo3::{create_exception, exceptions::PyException, prelude::*};
 
@@ -10,18 +15,30 @@ impl std::convert::From<Error> for PyErr {
     fn from(err: Error) -> PyErr {
         match err {
             // TODO better exceptions
-            error => NickelException::new_err(format!("unexpected error: {error:?}")),
+            error => NickelException::new_err(format!("{error:?}")),
         }
     }
 }
 
-// Some test function
+impl std::convert::From<SerializationError> for PyErr {
+    fn from(err: SerializationError) -> PyErr {
+        match err {
+            // TODO better exceptions
+            error => NickelException::new_err(format!("{error:?}")),
+        }
+    }
+}
+
+/// Evaluate from a Python str of a Nickel expression to a Python str of the resulting JSON.
 #[pyfunction]
 pub fn run(s: String) -> PyResult<String> {
     let mut program: Program<CBNCache> =
         Program::new_from_source(Cursor::new(s.to_string()), "python")?;
-    let term = program.eval()?;
-    Ok(term.to_string())
+    let term = program.eval_full()?;
+    serialize::validate(serialize::ExportFormat::Json, &term)?;
+    let json_string = serialize::to_string(serialize::ExportFormat::Json, &term)?;
+
+    Ok(json_string)
 }
 
 #[pymodule]