1 files changed, 147 insertions, 0 deletions
diff --git a/src/transpile_python.rs b/src/transpile_python.rs
new file mode 100644
index 0000000..d980e60
--- /dev/null
+++ b/src/transpile_python.rs
@@ -0,0 +1,147 @@
+
+extern crate modelica_parser;
+
+use self::modelica_parser::*;
+use errors::Result;
+
+pub trait TranspilePython {
+    fn transpile_python(&self) -> Result<String>;
+}
+
+pub trait TranspilePythonODE {
+    fn transpile_python_ode(&self) -> Result<String>;
+}
+
+
+impl TranspilePython for ModelicaModel {
+    fn transpile_python(&self) -> Result<String> {
+        let mut params = vec![];
+        let mut constants = vec![];
+        for (c, e) in self.get_constant_vars() {
+            if let Some(v) = e {
+                constants.push(format!("{} = {}", c, try!(v.transpile_python())));
+            } else {
+                params.push(c);
+            }
+        }
+        // HashMaps are unsorted, so we need to re-sort here
+        constants.sort();
+        params.sort();
+        let mut binds = vec![];
+        let mut outputs = vec![];
+        for eq in self.equations.iter() {
+            if let Expr::Ident(ref symb) = eq.lhs {
+                binds.push(format!("{} = {}",
+                    symb,
+                    try!(eq.rhs.transpile_python())));
+                outputs.push(symb.to_string());
+
+            } else {
+                bail!("Expected an identifier on LHS (in this partial implementation)")
+            }
+        }
+        let mut args: Vec<String> = self.get_free_vars().iter().map(|s| s.clone()).collect();
+        args.sort();
+        args.extend(params);
+        Ok(format!(
+r#"def {slug}({args}):
+    """{description}
+
+    Args:
+        {param_doc}
+
+    Returns array of:
+        {ret_doc}
+    """
+    {constants}
+    {binds}
+    return ({outputs})
+"#,
+                   description = self.description.clone().unwrap_or("(undocumented)".to_string()),
+                   param_doc = args.join("\n        "), // whitespace sensitive
+                   ret_doc = outputs.join("\n        "), // whitespace sensitive
+                   slug = self.name,
+                   args = args.join(", "),
+                   constants = constants.join("\n    "), // whitespace sensitive
+                   binds = binds.join("\n    "), // whitespace sensitive
+                   outputs = outputs.join(", ")))
+    }
+
+}
+
+impl TranspilePythonODE for ModelicaModel {
+
+    fn transpile_python_ode(&self) -> Result<String> {
+        let mut params = vec![];
+        let mut constants = vec![];
+        for (c, e) in self.get_constant_vars() {
+            if let Some(v) = e {
+                constants.push(format!("{} = {}", c, try!(v.transpile_python())));
+            } else {
+                params.push(c);
+            }
+        }
+        // HashMaps are unsorted, so we need to re-sort here
+        constants.sort();
+        params.sort();
+        let mut exprs = vec![];
+        for eq in self.equations.iter() {
+            if let Expr::Der(ref der_of) = eq.lhs {
+                if let &Expr::Ident(_) = der_of.as_ref() {
+                    // Ok
+                } else {
+                    bail!("Non-trivial derivatives not supported (aka, of non-variable expressions)");
+                }
+                exprs.push(try!(eq.rhs.transpile_python()));
+            } else {
+                bail!("Not a simple set of ODEs (aka, all derivatives on LHS of equations)");
+            }
+        }
+        let mut args: Vec<String> = self.get_free_vars().iter().map(|s| s.clone()).collect();
+        args.sort();
+        Ok(format!(
+r#"def {slug}_ode({params}):
+    def f({args}):
+        {constants}
+        return (
+            {expressions}
+        )
+    return f
+"#,
+                   slug = self.name,
+                   params = params.join(", "),
+                   args = args.join(", "),
+                   constants = constants.join("\n        "), // NB: whitespace
+                   expressions = exprs.join(",\n            "))) // NB: whitespace
+    }
+}
+
+impl TranspilePython for Expr {
+    fn transpile_python(&self) -> Result<String> {
+        use modelica_parser::Expr::*;
+        use modelica_parser::BinOperator::*;
+        match *self {
+            Integer(e) => Ok(format!("{}", e)),
+            Float(e) => Ok(format!("{}", e)),
+            Boolean(true) => Ok(format!("True")),
+            Boolean(false) => Ok(format!("False")),
+            StringLiteral(ref s) => Ok(format!("\"{}\"", s)),
+            Ident(ref e) => Ok(format!("{}", e)),
+            Der(_) => unimplemented!(),
+            Sign(_) => unimplemented!(),
+            MathUnaryExpr(func, ref e) => Ok(format!("{:?}({})", func, try!(e.transpile_python()))),
+            BinExpr(op, ref l, ref r) => {
+                // Have override for Python's exponentiation
+                let op_str = match op {
+                    Multiply => "*",
+                    Divide => "/",
+                    Exponentiate => "**",
+                    Add => "+",
+                    Subtract => "-",
+                };
+                Ok(format!("({} {} {})", try!(l.transpile_python()), op_str, try!(r.transpile_python())))
+            }
+            Array(_) => unimplemented!(),
+        }
+    }
+}