diff --git a/multigrid/src/eval.rs b/multigrid/src/eval.rs
index 7fe4c38..c530224 100644
--- a/multigrid/src/eval.rs
+++ b/multigrid/src/eval.rs
@@ -1,24 +1,14 @@
-use euler::GAMMA;
-use evalexpr::*;
-use ndarray::{azip, ArrayView, ArrayViewMut, Dimension};
+use ndarray::{ArrayView, ArrayViewMut, Dimension};
 use sbp::Float;
 
+pub mod evalexpr;
+
 #[derive(Clone, Debug)]
 pub enum Evaluator {
-    Pressure(EvaluatorPressure),
-    Conservation(EvaluatorConservation),
+    EvalExpr(evalexpr::Evaluator),
 }
 
-#[derive(Debug, Clone)]
-pub struct EvaluatorConservation {
-    pub(crate) ctx: HashMapContext,
-    pub(crate) rho: Node,
-    pub(crate) rhou: Node,
-    pub(crate) rhov: Node,
-    pub(crate) e: Node,
-}
-
-impl<D: ndarray::Dimension> euler::eval::Evaluator<D> for Evaluator {
+impl<D: Dimension> euler::eval::Evaluator<D> for Evaluator {
     fn evaluate(
         &self,
         t: Float,
@@ -30,338 +20,7 @@ impl<D: ndarray::Dimension> euler::eval::Evaluator<D> for Evaluator {
         e: ArrayViewMut<Float, D>,
     ) {
         match self {
-            Self::Conservation(c) => c.evaluate(t, x, y, rho, rhou, rhov, e),
-            Self::Pressure(p) => {
-                euler::eval::EvaluatorPressureWrapper::new(p).evaluate(t, x, y, rho, rhou, rhov, e)
-            }
+            Self::EvalExpr(c) => c.evaluate(t, x, y, rho, rhou, rhov, e),
         }
     }
 }
-
-#[derive(Debug, Clone)]
-pub struct EvaluatorPressure {
-    pub(crate) ctx: HashMapContext,
-    pub(crate) rho: Node,
-    pub(crate) u: Node,
-    pub(crate) v: Node,
-    pub(crate) p: Node,
-}
-
-struct ContextWrapper<'a> {
-    ctx: &'a HashMapContext,
-    x: Option<Value>,
-    y: Option<Value>,
-    t: Value,
-    rho: Option<Value>,
-    u: Option<Value>,
-    v: Option<Value>,
-    rhou: Option<Value>,
-    rhov: Option<Value>,
-    id: std::collections::HashMap<String, Value>,
-}
-
-impl<'a> ContextWrapper<'a> {
-    fn wrap(ctx: &'a HashMapContext, t: Value) -> Self {
-        Self {
-            ctx,
-            t,
-            x: None,
-            y: None,
-            rho: None,
-            rhou: None,
-            rhov: None,
-            u: None,
-            v: None,
-            id: std::collections::HashMap::new(),
-        }
-    }
-}
-
-impl Context for ContextWrapper<'_> {
-    fn get_value(&self, identifier: &str) -> Option<&Value> {
-        match identifier {
-            "t" => Some(&self.t),
-            "x" => self.x.as_ref(),
-            "y" => self.y.as_ref(),
-            "rho" => self.rho.as_ref(),
-            "rhou" => self.rhou.as_ref(),
-            "rhov" => self.rhov.as_ref(),
-            "u" => self.u.as_ref(),
-            "v" => self.v.as_ref(),
-            id => self.id.get(id).or_else(|| self.ctx.get_value(id)),
-        }
-    }
-
-    fn call_function(&self, identifier: &str, argument: &Value) -> EvalexprResult<Value> {
-        self.ctx.call_function(identifier, argument)
-    }
-}
-
-impl ContextWithMutableVariables for ContextWrapper<'_> {
-    fn set_value(&mut self, identifier: String, value: Value) -> EvalexprResult<()> {
-        self.id.insert(identifier, value);
-        Ok(())
-    }
-}
-
-impl<D: Dimension> euler::eval::Evaluator<D> for EvaluatorConservation {
-    fn evaluate(
-        &self,
-        t: Float,
-        x: ArrayView<Float, D>,
-        y: ArrayView<Float, D>,
-        mut rho: ArrayViewMut<Float, D>,
-        mut rhou: ArrayViewMut<Float, D>,
-        mut rhov: ArrayViewMut<Float, D>,
-        mut e: ArrayViewMut<Float, D>,
-    ) {
-        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
-
-        azip!((&x in &x.view(), &y in &y, rho in &mut rho) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-
-            *rho = self.rho.eval_number_with_context_mut(&mut ctx).unwrap();
-        });
-
-        azip!((&x in &x, &y in &y, &rho in &rho, rhou in &mut rhou) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-            ctx.rho = Some(rho.into());
-
-            *rhou = self.rhou.eval_number_with_context_mut(&mut ctx).unwrap();
-        });
-
-        azip!((&x in &x, &y in &y, &rho in &rho, rhov in &mut rhov) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-            ctx.rho = Some(rho.into());
-
-            *rhov = self.rhov.eval_number_with_context_mut(&mut ctx).unwrap();
-        });
-
-        azip!((&x in &x, &y in &y, &rho in &rho, &rhou in &rhou, &rhov in &rhov, e in &mut e) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-            ctx.rho = Some(rho.into());
-            ctx.rhou = Some(rhou.into());
-            ctx.rhov = Some(rhov.into());
-
-            *e = self.e.eval_number_with_context_mut(&mut ctx).unwrap();
-        });
-    }
-}
-
-impl<D: Dimension> euler::eval::EvaluatorPressure<D> for EvaluatorPressure {
-    fn rho(
-        &self,
-        t: Float,
-        x: ArrayView<Float, D>,
-        y: ArrayView<Float, D>,
-        mut rho: ArrayViewMut<Float, D>,
-    ) {
-        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
-
-        azip!((&x in &x, &y in &y, rho in &mut rho) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-
-            *rho = self.rho.eval_number_with_context_mut(&mut ctx).unwrap();
-        })
-    }
-
-    fn u(
-        &self,
-        t: Float,
-        x: ArrayView<Float, D>,
-        y: ArrayView<Float, D>,
-        rho: ArrayView<Float, D>,
-        mut u: ArrayViewMut<Float, D>,
-    ) {
-        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
-
-        azip!((&x in &x, &y in &y, &rho in &rho, u in &mut u) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-            ctx.rho = Some(rho.into());
-
-            *u = self.u.eval_number_with_context_mut(&mut ctx).unwrap();
-        })
-    }
-    fn v(
-        &self,
-        t: Float,
-        x: ArrayView<Float, D>,
-        y: ArrayView<Float, D>,
-        rho: ArrayView<Float, D>,
-        mut v: ArrayViewMut<Float, D>,
-    ) {
-        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
-
-        azip!((&x in &x, &y in &y, &rho in &rho, v in &mut v) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-            ctx.rho = Some(rho.into());
-
-            *v = self.v.eval_number_with_context_mut(&mut ctx).unwrap();
-        })
-    }
-
-    fn p(
-        &self,
-        t: Float,
-        x: ArrayView<Float, D>,
-        y: ArrayView<Float, D>,
-        rho: ArrayView<Float, D>,
-        u: ArrayView<Float, D>,
-        v: ArrayView<Float, D>,
-        mut p: ArrayViewMut<Float, D>,
-    ) {
-        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
-
-        azip!((&x in &x, &y in &y, &rho in &rho, &u in &u, &v in &v, p in &mut p) {
-            ctx.x = Some(x.into());
-            ctx.y = Some(y.into());
-            ctx.rho = Some(rho.into());
-            ctx.u = Some(u.into());
-            ctx.v = Some(v.into());
-
-            *p = self.p.eval_number_with_context_mut(&mut ctx).unwrap();
-        })
-    }
-}
-
-#[test]
-fn append_default_context() {
-    let basic_ctx = context_map! {
-        "a" => 2,
-    }
-    .unwrap();
-
-    let mut ctx = ContextWrapper::wrap(&basic_ctx, Value::from(4));
-    ctx.x = Some(3.into());
-
-    let expr = "a + x + t";
-
-    let node = build_operator_tree(expr).unwrap();
-
-    assert_eq!(node.eval_with_context(&ctx).unwrap().as_int().unwrap(), 9);
-}
-
-pub fn default_context() -> HashMapContext {
-    let mut context = math_consts_context! {}.unwrap();
-    let gamma = *GAMMA.get().expect("GAMMA is not defined");
-    context.set_value("GAMMA".into(), gamma.into()).unwrap();
-
-    context
-        .set_function(
-            "if".into(),
-            Function::new(|arg| {
-                let arg = arg.as_tuple()?;
-                if arg.len() != 3 {
-                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
-                        expected: 3,
-                        actual: arg.len(),
-                    });
-                }
-                let b = arg[0].as_boolean()?;
-                if b {
-                    Ok(arg[1].clone())
-                } else {
-                    Ok(arg[2].clone())
-                }
-            }),
-        )
-        .unwrap();
-
-    context
-        .set_function(
-            "case".into(),
-            Function::new(|arg| {
-                let mut arg = arg.as_tuple()?;
-                if arg.len() % 2 == 0 {
-                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
-                        expected: arg.len() + 1,
-                        actual: arg.len(),
-                    });
-                }
-                //let mut arg = arg.as_slice();
-                while arg.len() > 2 {
-                    let boolean = arg.remove(0);
-                    let value = arg.remove(0);
-
-                    if boolean.as_boolean()? {
-                        return Ok(value);
-                    }
-                }
-                Ok(arg.pop().unwrap())
-            }),
-        )
-        .unwrap();
-
-    context
-        .set_function(
-            "math::atan2".into(),
-            Function::new(|arg| {
-                let arg = arg.as_tuple()?;
-                if arg.len() != 2 {
-                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
-                        expected: 2,
-                        actual: arg.len(),
-                    });
-                }
-                let s = arg[0].as_number()?;
-                let o = arg[1].as_number()?;
-                Ok(s.atan2(o).into())
-            }),
-        )
-        .unwrap();
-
-    context
-        .set_function(
-            "math::hypot".into(),
-            Function::new(|arg| {
-                let arg = arg.as_tuple()?;
-                if arg.len() != 2 {
-                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
-                        expected: 2,
-                        actual: arg.len(),
-                    });
-                }
-                let s = arg[0].as_number()?;
-                let o = arg[1].as_number()?;
-                Ok(s.hypot(o).into())
-            }),
-        )
-        .unwrap();
-
-    context
-        .set_function(
-            "math::exp".into(),
-            Function::new(|arg| {
-                let arg = arg.as_number()?;
-                Ok(arg.exp().into())
-            }),
-        )
-        .unwrap();
-
-    context
-        .set_function(
-            "math::pow".into(),
-            Function::new(|arg| {
-                let arg = arg.as_tuple()?;
-                if arg.len() != 2 {
-                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
-                        expected: 2,
-                        actual: arg.len(),
-                    });
-                }
-                let s = arg[0].as_number()?;
-                let o = arg[1].as_number()?;
-                Ok(s.powf(o).into())
-            }),
-        )
-        .unwrap();
-
-    context
-}
diff --git a/multigrid/src/eval/evalexpr.rs b/multigrid/src/eval/evalexpr.rs
new file mode 100644
index 0000000..939f7e7
--- /dev/null
+++ b/multigrid/src/eval/evalexpr.rs
@@ -0,0 +1,367 @@
+use euler::GAMMA;
+use evalexpr::*;
+use ndarray::{azip, ArrayView, ArrayViewMut, Dimension};
+use sbp::Float;
+
+#[derive(Clone, Debug)]
+pub enum Evaluator {
+    Pressure(EvaluatorPressure),
+    Conservation(EvaluatorConservation),
+}
+
+#[derive(Debug, Clone)]
+pub struct EvaluatorConservation {
+    pub(crate) ctx: HashMapContext,
+    pub(crate) rho: Node,
+    pub(crate) rhou: Node,
+    pub(crate) rhov: Node,
+    pub(crate) e: Node,
+}
+
+impl<D: Dimension> euler::eval::Evaluator<D> for Evaluator {
+    fn evaluate(
+        &self,
+        t: Float,
+        x: ArrayView<Float, D>,
+        y: ArrayView<Float, D>,
+        rho: ArrayViewMut<Float, D>,
+        rhou: ArrayViewMut<Float, D>,
+        rhov: ArrayViewMut<Float, D>,
+        e: ArrayViewMut<Float, D>,
+    ) {
+        match self {
+            Self::Conservation(c) => c.evaluate(t, x, y, rho, rhou, rhov, e),
+            Self::Pressure(p) => {
+                euler::eval::EvaluatorPressureWrapper::new(p).evaluate(t, x, y, rho, rhou, rhov, e)
+            }
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct EvaluatorPressure {
+    pub(crate) ctx: HashMapContext,
+    pub(crate) rho: Node,
+    pub(crate) u: Node,
+    pub(crate) v: Node,
+    pub(crate) p: Node,
+}
+
+struct ContextWrapper<'a> {
+    ctx: &'a HashMapContext,
+    x: Option<Value>,
+    y: Option<Value>,
+    t: Value,
+    rho: Option<Value>,
+    u: Option<Value>,
+    v: Option<Value>,
+    rhou: Option<Value>,
+    rhov: Option<Value>,
+    id: std::collections::HashMap<String, Value>,
+}
+
+impl<'a> ContextWrapper<'a> {
+    fn wrap(ctx: &'a HashMapContext, t: Value) -> Self {
+        Self {
+            ctx,
+            t,
+            x: None,
+            y: None,
+            rho: None,
+            rhou: None,
+            rhov: None,
+            u: None,
+            v: None,
+            id: std::collections::HashMap::new(),
+        }
+    }
+}
+
+impl Context for ContextWrapper<'_> {
+    fn get_value(&self, identifier: &str) -> Option<&Value> {
+        match identifier {
+            "t" => Some(&self.t),
+            "x" => self.x.as_ref(),
+            "y" => self.y.as_ref(),
+            "rho" => self.rho.as_ref(),
+            "rhou" => self.rhou.as_ref(),
+            "rhov" => self.rhov.as_ref(),
+            "u" => self.u.as_ref(),
+            "v" => self.v.as_ref(),
+            id => self.id.get(id).or_else(|| self.ctx.get_value(id)),
+        }
+    }
+
+    fn call_function(&self, identifier: &str, argument: &Value) -> EvalexprResult<Value> {
+        self.ctx.call_function(identifier, argument)
+    }
+}
+
+impl ContextWithMutableVariables for ContextWrapper<'_> {
+    fn set_value(&mut self, identifier: String, value: Value) -> EvalexprResult<()> {
+        self.id.insert(identifier, value);
+        Ok(())
+    }
+}
+
+impl<D: Dimension> euler::eval::Evaluator<D> for EvaluatorConservation {
+    fn evaluate(
+        &self,
+        t: Float,
+        x: ArrayView<Float, D>,
+        y: ArrayView<Float, D>,
+        mut rho: ArrayViewMut<Float, D>,
+        mut rhou: ArrayViewMut<Float, D>,
+        mut rhov: ArrayViewMut<Float, D>,
+        mut e: ArrayViewMut<Float, D>,
+    ) {
+        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
+
+        azip!((&x in &x.view(), &y in &y, rho in &mut rho) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+
+            *rho = self.rho.eval_number_with_context_mut(&mut ctx).unwrap();
+        });
+
+        azip!((&x in &x, &y in &y, &rho in &rho, rhou in &mut rhou) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+            ctx.rho = Some(rho.into());
+
+            *rhou = self.rhou.eval_number_with_context_mut(&mut ctx).unwrap();
+        });
+
+        azip!((&x in &x, &y in &y, &rho in &rho, rhov in &mut rhov) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+            ctx.rho = Some(rho.into());
+
+            *rhov = self.rhov.eval_number_with_context_mut(&mut ctx).unwrap();
+        });
+
+        azip!((&x in &x, &y in &y, &rho in &rho, &rhou in &rhou, &rhov in &rhov, e in &mut e) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+            ctx.rho = Some(rho.into());
+            ctx.rhou = Some(rhou.into());
+            ctx.rhov = Some(rhov.into());
+
+            *e = self.e.eval_number_with_context_mut(&mut ctx).unwrap();
+        });
+    }
+}
+
+impl<D: Dimension> euler::eval::EvaluatorPressure<D> for EvaluatorPressure {
+    fn rho(
+        &self,
+        t: Float,
+        x: ArrayView<Float, D>,
+        y: ArrayView<Float, D>,
+        mut rho: ArrayViewMut<Float, D>,
+    ) {
+        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
+
+        azip!((&x in &x, &y in &y, rho in &mut rho) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+
+            *rho = self.rho.eval_number_with_context_mut(&mut ctx).unwrap();
+        })
+    }
+
+    fn u(
+        &self,
+        t: Float,
+        x: ArrayView<Float, D>,
+        y: ArrayView<Float, D>,
+        rho: ArrayView<Float, D>,
+        mut u: ArrayViewMut<Float, D>,
+    ) {
+        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
+
+        azip!((&x in &x, &y in &y, &rho in &rho, u in &mut u) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+            ctx.rho = Some(rho.into());
+
+            *u = self.u.eval_number_with_context_mut(&mut ctx).unwrap();
+        })
+    }
+    fn v(
+        &self,
+        t: Float,
+        x: ArrayView<Float, D>,
+        y: ArrayView<Float, D>,
+        rho: ArrayView<Float, D>,
+        mut v: ArrayViewMut<Float, D>,
+    ) {
+        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
+
+        azip!((&x in &x, &y in &y, &rho in &rho, v in &mut v) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+            ctx.rho = Some(rho.into());
+
+            *v = self.v.eval_number_with_context_mut(&mut ctx).unwrap();
+        })
+    }
+
+    fn p(
+        &self,
+        t: Float,
+        x: ArrayView<Float, D>,
+        y: ArrayView<Float, D>,
+        rho: ArrayView<Float, D>,
+        u: ArrayView<Float, D>,
+        v: ArrayView<Float, D>,
+        mut p: ArrayViewMut<Float, D>,
+    ) {
+        let mut ctx = ContextWrapper::wrap(&self.ctx, t.into());
+
+        azip!((&x in &x, &y in &y, &rho in &rho, &u in &u, &v in &v, p in &mut p) {
+            ctx.x = Some(x.into());
+            ctx.y = Some(y.into());
+            ctx.rho = Some(rho.into());
+            ctx.u = Some(u.into());
+            ctx.v = Some(v.into());
+
+            *p = self.p.eval_number_with_context_mut(&mut ctx).unwrap();
+        })
+    }
+}
+
+#[test]
+fn append_default_context() {
+    let basic_ctx = context_map! {
+        "a" => 2,
+    }
+    .unwrap();
+
+    let mut ctx = ContextWrapper::wrap(&basic_ctx, Value::from(4));
+    ctx.x = Some(3.into());
+
+    let expr = "a + x + t";
+
+    let node = build_operator_tree(expr).unwrap();
+
+    assert_eq!(node.eval_with_context(&ctx).unwrap().as_int().unwrap(), 9);
+}
+
+pub fn default_context() -> HashMapContext {
+    let mut context = math_consts_context! {}.unwrap();
+    let gamma = *GAMMA.get().expect("GAMMA is not defined");
+    context.set_value("GAMMA".into(), gamma.into()).unwrap();
+
+    context
+        .set_function(
+            "if".into(),
+            Function::new(|arg| {
+                let arg = arg.as_tuple()?;
+                if arg.len() != 3 {
+                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
+                        expected: 3,
+                        actual: arg.len(),
+                    });
+                }
+                let b = arg[0].as_boolean()?;
+                if b {
+                    Ok(arg[1].clone())
+                } else {
+                    Ok(arg[2].clone())
+                }
+            }),
+        )
+        .unwrap();
+
+    context
+        .set_function(
+            "case".into(),
+            Function::new(|arg| {
+                let mut arg = arg.as_tuple()?;
+                if arg.len() % 2 == 0 {
+                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
+                        expected: arg.len() + 1,
+                        actual: arg.len(),
+                    });
+                }
+                //let mut arg = arg.as_slice();
+                while arg.len() > 2 {
+                    let boolean = arg.remove(0);
+                    let value = arg.remove(0);
+
+                    if boolean.as_boolean()? {
+                        return Ok(value);
+                    }
+                }
+                Ok(arg.pop().unwrap())
+            }),
+        )
+        .unwrap();
+
+    context
+        .set_function(
+            "math::atan2".into(),
+            Function::new(|arg| {
+                let arg = arg.as_tuple()?;
+                if arg.len() != 2 {
+                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
+                        expected: 2,
+                        actual: arg.len(),
+                    });
+                }
+                let s = arg[0].as_number()?;
+                let o = arg[1].as_number()?;
+                Ok(s.atan2(o).into())
+            }),
+        )
+        .unwrap();
+
+    context
+        .set_function(
+            "math::hypot".into(),
+            Function::new(|arg| {
+                let arg = arg.as_tuple()?;
+                if arg.len() != 2 {
+                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
+                        expected: 2,
+                        actual: arg.len(),
+                    });
+                }
+                let s = arg[0].as_number()?;
+                let o = arg[1].as_number()?;
+                Ok(s.hypot(o).into())
+            }),
+        )
+        .unwrap();
+
+    context
+        .set_function(
+            "math::exp".into(),
+            Function::new(|arg| {
+                let arg = arg.as_number()?;
+                Ok(arg.exp().into())
+            }),
+        )
+        .unwrap();
+
+    context
+        .set_function(
+            "math::pow".into(),
+            Function::new(|arg| {
+                let arg = arg.as_tuple()?;
+                if arg.len() != 2 {
+                    return Err(error::EvalexprError::WrongFunctionArgumentAmount {
+                        expected: 2,
+                        actual: arg.len(),
+                    });
+                }
+                let s = arg[0].as_number()?;
+                let o = arg[1].as_number()?;
+                Ok(s.powf(o).into())
+            }),
+        )
+        .unwrap();
+
+    context
+}
diff --git a/multigrid/src/parsing.rs b/multigrid/src/parsing.rs
index c5f43e1..e064dd8 100644
--- a/multigrid/src/parsing.rs
+++ b/multigrid/src/parsing.rs
@@ -9,7 +9,7 @@ use crate::input;
 impl TryFrom<input::Expressions> for eval::Evaluator {
     type Error = ();
     fn try_from(expr: input::Expressions) -> Result<Self, Self::Error> {
-        let mut context = eval::default_context();
+        let mut context = eval::evalexpr::default_context();
         match expr {
             input::Expressions::Pressure(input::ExpressionsPressure {
                 globals,
@@ -27,13 +27,15 @@ impl TryFrom<input::Expressions> for eval::Evaluator {
                     evalexpr::build_operator_tree(&v).unwrap(),
                     evalexpr::build_operator_tree(&p).unwrap(),
                 ];
-                Ok(eval::Evaluator::Pressure(eval::EvaluatorPressure {
-                    ctx: context,
-                    rho,
-                    u,
-                    v,
-                    p,
-                }))
+                Ok(eval::Evaluator::EvalExpr(
+                    eval::evalexpr::Evaluator::Pressure(eval::evalexpr::EvaluatorPressure {
+                        ctx: context,
+                        rho,
+                        u,
+                        v,
+                        p,
+                    }),
+                ))
             }
             input::Expressions::Conservation(input::ExpressionsConservation {
                 globals,
@@ -51,13 +53,17 @@ impl TryFrom<input::Expressions> for eval::Evaluator {
                     evalexpr::build_operator_tree(&rhov).unwrap(),
                     evalexpr::build_operator_tree(&e).unwrap(),
                 ];
-                Ok(eval::Evaluator::Conservation(eval::EvaluatorConservation {
-                    ctx: context,
-                    rho,
-                    rhou,
-                    rhov,
-                    e,
-                }))
+                Ok(eval::Evaluator::EvalExpr(
+                    eval::evalexpr::Evaluator::Conservation(
+                        eval::evalexpr::EvaluatorConservation {
+                            ctx: context,
+                            rho,
+                            rhou,
+                            rhov,
+                            e,
+                        },
+                    ),
+                ))
             }
         }
     }