implement Clone for Expression (really works)

src/compiler.rs

@@ -6,7 +6,7 @@ use std::{
 
 use derive_new::new;
 use derive_wrapper::{AsRef, From};
-use fasteval::{Compiler, Evaler, Instruction, Slab};
+use fasteval::{Compiler, EvalNamespace, Evaler, Instruction, Slab};
 use thiserror::Error;
 
 const SAMPLE_RATE: u16 = 48000;
@@ -118,13 +118,16 @@ impl Token for Slope<'_> {
 #[derive(new)]
 #[cfg_attr(any(debug_assertions, test), derive(Debug))]
 pub struct Expression {
+    from: String,
     pub(crate) instruction: Instruction,
     pub(crate) slab: Slab,
 }
 
 impl Clone for Expression {
     fn clone(&self) -> Self {
-        unimplemented!()
+        self.from
+            .parse()
+            .expect(&format!("expression {self:?} have an invalid from"))
     }
 }
 
@@ -143,7 +146,11 @@ impl FromStr for Expression {
             .parse(s, &mut slab.ps)?
             .from(&slab.ps)
             .compile(&slab.ps, &mut slab.cs);
-        Ok(Expression::new(instruction, slab))
+        Ok(Expression::new(
+            s.trim_start().trim_end().to_string(),
+            instruction,
+            slab,
+        ))
     }
 }
 
@@ -197,24 +204,32 @@ impl Context {
         *self.get_mut('t')? += 1f64 / SAMPLE_RATE as f64;
         {
             let changes = self
-            .slopes
-            .iter()
-            .map(
-                |(v, Expression { instruction, slab })| -> Result<(char, f64), fasteval::Error> {
-                    Ok((
-                        *v,
-                        instruction.eval(
+                .slopes
+                .iter()
+                .map(
+                    |(
+                        v,
+                        Expression {
+                            from: _,
+                            instruction,
                             slab,
-                            &mut self
-                                .variables
-                                .iter()
-                                .map(|(c, f)| (c.to_string(), *f))
-                                .collect::<BTreeMap<String, f64>>(),
-                        )?,
-                    ))
-                },
-            )
-            .collect::<Result<Vec<(char, f64)>, fasteval::Error>>()?;
+                        },
+                    )|
+                     -> Result<(char, f64), fasteval::Error> {
+                        Ok((
+                            *v,
+                            instruction.eval(
+                                slab,
+                                &mut self
+                                    .variables
+                                    .iter()
+                                    .map(|(c, f)| (c.to_string(), *f))
+                                    .collect::<BTreeMap<String, f64>>(),
+                            )?,
+                        ))
+                    },
+                )
+                .collect::<Result<Vec<(char, f64)>, fasteval::Error>>()?;
             for (variable, new_value) in changes {
                 *self.get_mut(variable)? = new_value;
             }
@@ -229,11 +244,20 @@ impl Context {
             .collect()
     }
 
-    pub fn eval(
+    pub fn eval(&self, expr: &Expression) -> Result<f64, fasteval::Error> {
+        self.eval_with(expr, &mut self.namespace_generator())
+    }
+
+    pub fn eval_with(
         &self,
-        Expression { instruction, slab }: &Expression,
+        Expression {
+            from: _,
+            instruction,
+            slab,
+        }: &Expression,
+        ns: &mut impl EvalNamespace,
     ) -> Result<f64, fasteval::Error> {
-        instruction.eval(&slab, &mut self.namespace_generator())
+        instruction.eval(&slab, ns)
     }
 
     pub fn render(&mut self, n: Option<u8>) -> Result<Vec<f64>, CompilerError> {
@@ -242,13 +266,8 @@ impl Context {
             let mut result = Vec::new();
             while (self.current_length()? * SAMPLE_RATE as f64) > *self.get('t')? - curr_t {
                 {
-                    let Expression { instruction, slab } = &self.instrument;
-                    result.push(instruction.eval(&slab, &mut {
-                        let mut map = self
-                            .variables
-                            .iter()
-                            .map(|(c, f)| (format!("{c}"), *f))
-                            .collect::<BTreeMap<String, f64>>();
+                    result.push(self.eval_with(&self.instrument, &mut {
+                        let mut map = self.namespace_generator();
                         map.insert('n'.to_string(), note as f64);
                         map
                     })?);
@@ -264,3 +283,14 @@ impl Context {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::compiler::Expression;
+
+    #[test]
+    fn expression_is_clone() {
+        let expr: Expression = "1 + 5 / x".parse().unwrap();
+        assert_eq!(expr, expr.clone());
+    }
+}