diff --git a/multigrid/src/eval.rs b/multigrid/src/eval.rs
index c530224..8b4b903 100644
--- a/multigrid/src/eval.rs
+++ b/multigrid/src/eval.rs
@@ -1,5 +1,6 @@
 use ndarray::{ArrayView, ArrayViewMut, Dimension};
 use sbp::Float;
+use std::convert::{TryFrom, TryInto};
 
 pub mod evalexpr;
 
@@ -24,3 +25,10 @@ impl<D: Dimension> euler::eval::Evaluator<D> for Evaluator {
         }
     }
 }
+
+impl TryFrom<crate::input::Expressions> for Evaluator {
+    type Error = ();
+    fn try_from(expr: crate::input::Expressions) -> Result<Self, Self::Error> {
+        Ok(Self::EvalExpr(expr.try_into()?))
+    }
+}
diff --git a/multigrid/src/eval/evalexpr.rs b/multigrid/src/eval/evalexpr.rs
index 939f7e7..a0511e5 100644
--- a/multigrid/src/eval/evalexpr.rs
+++ b/multigrid/src/eval/evalexpr.rs
@@ -2,6 +2,9 @@ use euler::GAMMA;
 use evalexpr::*;
 use ndarray::{azip, ArrayView, ArrayViewMut, Dimension};
 use sbp::Float;
+use std::convert::TryFrom;
+
+use crate::input;
 
 #[derive(Clone, Debug)]
 pub enum Evaluator {
@@ -9,6 +12,63 @@ pub enum Evaluator {
     Conservation(EvaluatorConservation),
 }
 
+impl TryFrom<input::Expressions> for Evaluator {
+    type Error = ();
+    fn try_from(expr: input::Expressions) -> Result<Self, Self::Error> {
+        let mut context = default_context();
+        match expr {
+            input::Expressions::Pressure(input::ExpressionsPressure {
+                globals,
+                rho,
+                u,
+                v,
+                p,
+            }) => {
+                if let Some(globals) = &globals {
+                    evalexpr::eval_with_context_mut(globals, &mut context).unwrap();
+                }
+                let [rho, u, v, p] = [
+                    evalexpr::build_operator_tree(&rho).unwrap(),
+                    evalexpr::build_operator_tree(&u).unwrap(),
+                    evalexpr::build_operator_tree(&v).unwrap(),
+                    evalexpr::build_operator_tree(&p).unwrap(),
+                ];
+                Ok(Evaluator::Pressure(EvaluatorPressure {
+                    ctx: context,
+                    rho,
+                    u,
+                    v,
+                    p,
+                }))
+            }
+            input::Expressions::Conservation(input::ExpressionsConservation {
+                globals,
+                rho,
+                rhou,
+                rhov,
+                e,
+            }) => {
+                if let Some(globals) = &globals {
+                    evalexpr::eval_with_context_mut(globals, &mut context).unwrap();
+                }
+                let [rho, rhou, rhov, e] = [
+                    evalexpr::build_operator_tree(&rho).unwrap(),
+                    evalexpr::build_operator_tree(&rhou).unwrap(),
+                    evalexpr::build_operator_tree(&rhov).unwrap(),
+                    evalexpr::build_operator_tree(&e).unwrap(),
+                ];
+                Ok(Evaluator::Conservation(EvaluatorConservation {
+                    ctx: context,
+                    rho,
+                    rhou,
+                    rhov,
+                    e,
+                }))
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub struct EvaluatorConservation {
     pub(crate) ctx: HashMapContext,
diff --git a/multigrid/src/parsing.rs b/multigrid/src/parsing.rs
index e064dd8..f0d5c14 100644
--- a/multigrid/src/parsing.rs
+++ b/multigrid/src/parsing.rs
@@ -6,69 +6,6 @@ use sbp::Float;
 use crate::eval;
 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::evalexpr::default_context();
-        match expr {
-            input::Expressions::Pressure(input::ExpressionsPressure {
-                globals,
-                rho,
-                u,
-                v,
-                p,
-            }) => {
-                if let Some(globals) = &globals {
-                    evalexpr::eval_with_context_mut(globals, &mut context).unwrap();
-                }
-                let [rho, u, v, p] = [
-                    evalexpr::build_operator_tree(&rho).unwrap(),
-                    evalexpr::build_operator_tree(&u).unwrap(),
-                    evalexpr::build_operator_tree(&v).unwrap(),
-                    evalexpr::build_operator_tree(&p).unwrap(),
-                ];
-                Ok(eval::Evaluator::EvalExpr(
-                    eval::evalexpr::Evaluator::Pressure(eval::evalexpr::EvaluatorPressure {
-                        ctx: context,
-                        rho,
-                        u,
-                        v,
-                        p,
-                    }),
-                ))
-            }
-            input::Expressions::Conservation(input::ExpressionsConservation {
-                globals,
-                rho,
-                rhou,
-                rhov,
-                e,
-            }) => {
-                if let Some(globals) = &globals {
-                    evalexpr::eval_with_context_mut(globals, &mut context).unwrap();
-                }
-                let [rho, rhou, rhov, e] = [
-                    evalexpr::build_operator_tree(&rho).unwrap(),
-                    evalexpr::build_operator_tree(&rhou).unwrap(),
-                    evalexpr::build_operator_tree(&rhov).unwrap(),
-                    evalexpr::build_operator_tree(&e).unwrap(),
-                ];
-                Ok(eval::Evaluator::EvalExpr(
-                    eval::evalexpr::Evaluator::Conservation(
-                        eval::evalexpr::EvaluatorConservation {
-                            ctx: context,
-                            rho,
-                            rhou,
-                            rhov,
-                            e,
-                        },
-                    ),
-                ))
-            }
-        }
-    }
-}
-
 impl TryFrom<input::InitialConditions> for InitialConditions {
     type Error = ();
     fn try_from(v: input::InitialConditions) -> Result<Self, Self::Error> {