1 files changed, 38 insertions, 0 deletions
diff --git a/src/modelica_ast.rs b/src/modelica_ast.rs
index 68eafaf..9e25b1b 100644
--- a/src/modelica_ast.rs
+++ b/src/modelica_ast.rs
@@ -1,5 +1,6 @@
 
 use std::fmt::{Debug, Formatter, Error};
+use std::collections::HashMap;
 
 #[derive(PartialEq)]
 pub struct ModelicaModel {
@@ -59,6 +60,43 @@ pub enum BinOperator {
     Subtract,
 }
 
+//// Helpers
+
+impl ModelicaModel {
+
+    pub fn get_constant_vars(&self) -> HashMap<String,Expr> {
+        let mut binds = HashMap::new();
+        for c in &self.components {
+            match c.prefix {
+                Some(ComponentPrefix::Constant) => { binds.insert(c.name.clone(), Expr::Integer(123)); },
+                Some(ComponentPrefix::Parameter) => { binds.insert(c.name.clone(), Expr::Float(4.56)); },
+                _ => (),
+            }
+        }
+        binds
+    }
+
+    pub fn get_free_vars(&self) -> Vec<String> {
+        // Start with components, and remove constants and parameters
+        let vars = self.components.iter().filter(|v| match v.prefix {
+                Some(ComponentPrefix::Constant) | Some(ComponentPrefix::Parameter) => false,
+                _ => true,
+            });
+
+        // Remove LHS (bound) vars
+        let mut outputs = vec![];
+        for eq in self.equations.iter() {
+            // TODO:
+            if let Expr::Ident(ref symb) = eq.lhs {
+                outputs.push(symb.to_string());
+            }
+        }
+        let vars = vars.filter(|v| !outputs.contains(&v.name));
+
+        vars.map(|c| c.name.clone()).collect()
+    }
+}
+
 //// Debug Implementations
 
 impl Debug for ModelicaModel {