From fefe370e0bdb3e80427a26a3eb2727b47e22ed03 Mon Sep 17 00:00:00 2001
From: bnewbold <bnewbold@robocracy.org>
Date: Mon, 16 Jan 2017 18:04:14 -0800
Subject: add 'ode' transpile variant for javascript

---
 src/bin/mt-webface.rs |  3 ++-
 src/transpile_js.rs   | 56 ++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/src/bin/mt-webface.rs b/src/bin/mt-webface.rs
index b26e4fe..59b0621 100644
--- a/src/bin/mt-webface.rs
+++ b/src/bin/mt-webface.rs
@@ -20,7 +20,7 @@ use pencil::{redirect, abort};
 use pencil::method::{Get, Post};
 use regex::Regex;
 use modelthing::transpile_scheme::TranspileScheme;
-use modelthing::transpile_js::TranspileJS;
+use modelthing::transpile_js::{TranspileJS, TranspileJSODE};
 use modelthing::repr_latex::ReprLaTeX;
 
 /*
@@ -112,6 +112,7 @@ fn model_repr(r: &mut Request) -> PencilResult {
             match format {
                 "scheme" => Ok(Response::from(me.ast.transpile_scheme().unwrap())),
                 "javascript" => Ok(Response::from(me.ast.transpile_js().unwrap())),
+                "javascript_ode" => Ok(Response::from(me.ast.transpile_js_ode().unwrap())),
                 "latex" => Ok(Response::from(me.ast.repr_latex().unwrap())),
                 _ => abort(403),
             }
diff --git a/src/transpile_js.rs b/src/transpile_js.rs
index 219364a..225aa99 100644
--- a/src/transpile_js.rs
+++ b/src/transpile_js.rs
@@ -8,6 +8,10 @@ pub trait TranspileJS {
     fn transpile_js(&self) -> Result<String>;
 }
 
+pub trait TranspileJSODE {
+    fn transpile_js_ode(&self) -> Result<String>;
+}
+
 
 impl TranspileJS for ModelicaModel {
     fn transpile_js(&self) -> Result<String> {
@@ -28,17 +32,59 @@ impl TranspileJS for ModelicaModel {
             }
         }
         let args: Vec<String> = self.get_free_vars().iter().map(|s| s.clone()).collect();
-        Ok(format!(r#"function {slug}({args}) {{
+        Ok(format!(r#"function ({args}) {{
                 {constants}
                 {binds}
                 return [{outputs}];
-        }}"#,
-                   slug = "f",
+        }};"#,
                    args = args.join(", "),
                    constants = constants.join("\n    "),
                    binds = binds.join("\n    "),
                    outputs = outputs.join(", ")))
     }
+
+}
+
+impl TranspileJSODE for ModelicaModel {
+
+    fn transpile_js_ode(&self) -> Result<String> {
+        // TODO: distinguish true constants from parameters?
+        let mut params: Vec<String> = vec![];
+        let mut constants = vec![];
+        for (c, e) in self.get_constant_vars() {
+            if let Some(v) = e {
+                constants.push(format!("var {} = {};", c, try!(v.transpile_js())));
+            } else {
+                params.push(c);
+            }
+        }
+        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_js()));
+            } else {
+                bail!("Not a simple set of ODEs (aka, all derivatives on LHS of equations)");
+            }
+        }
+        let args: Vec<String> = self.get_free_vars().iter().map(|s| s.clone()).collect();
+        Ok(format!(r#"function ({params}) {{
+            return function({args}) {{
+                {constants}
+                return [
+                    {expressions}
+                ];
+            }};
+        }};"#,
+                   params = params.join(", "),
+                   args = args.join(", "),
+                   constants = constants.join("\n    "),
+                   expressions = exprs.join(",\n    ")))
+    }
 }
 
 impl TranspileJS for Expr {
@@ -51,8 +97,8 @@ impl TranspileJS for Expr {
             Boolean(false) => Ok(format!("false")),
             StringLiteral(ref s) => Ok(format!("\"{}\"", s)),
             Ident(ref e) => Ok(format!("{}", e)),
-            Der(ref e) => Ok(format!("der({})", try!(e.transpile_js()))),
-            Sign(ref e) => Ok(format!("sign({})", try!(e.transpile_js()))),
+            Der(_) => unimplemented!(),
+            Sign(_) => unimplemented!(),
             MathUnaryExpr(func, ref e) => Ok(format!("{:?}({})", func, try!(e.transpile_js()))),
             BinExpr(op, ref l, ref r) => {
                 Ok(format!("({} {:?} {})", try!(l.transpile_js()), op, try!(r.transpile_js())))
-- 
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