refactor error handling with error_chain

2 files changed, 33 insertions, 8 deletions

diff --git a/src/bin/mt-tool.rs b/src/bin/mt-tool.rs
index c04d5ab..e554636 100644
--- a/src/bin/mt-tool.rs
+++ b/src/bin/mt-tool.rs
@@ -7,6 +7,7 @@ extern crate modelica_parser;
 use modelthing::transpile_scheme::TranspileScheme;
 use modelthing::transpile_js::TranspileJS;
 use modelthing::modelica_model::ModelicaModelExt;
+use modelthing::Result;
 use clap::{App, SubCommand};
 use std::io::Read;
 use std::fs::File;
@@ -35,7 +36,7 @@ fn parse_modelica_files(paths: Vec<String>) {
     }
 }
 
-fn main() {
+fn run() -> Result<()> {
 
     let matches = App::new("mt-tool")
         .version(env!("CARGO_PKG_VERSION"))
@@ -69,18 +70,18 @@ fn main() {
             let dir = Path::new(subm.value_of("DIR").unwrap());
             let indep = subm.values_of_lossy("indep").unwrap();
             let dep = subm.values_of_lossy("dep").unwrap();
-            let me = modelthing::load_model_entry(dir).unwrap();
-            println!("{:?}", me.ast.solve_for(indep, dep));
+            let me = try!(modelthing::load_model_entry(dir));
+            println!("{:?}", try!(me.ast.solve_for(indep, dep)));
         },
         ("transpile_scheme", Some(subm)) => {
             let dir = Path::new(subm.value_of("DIR").unwrap());
-            let me = modelthing::load_model_entry(dir).unwrap();
-            println!("{}", me.ast.repr_scheme().unwrap());
+            let me = try!(modelthing::load_model_entry(dir));
+            println!("{}", try!(me.ast.repr_scheme()));
         },
         ("transpile_js", Some(subm)) => {
             let dir = Path::new(subm.value_of("DIR").unwrap());
-            let me = modelthing::load_model_entry(dir).unwrap();
-            println!("{}", me.ast.repr_js().unwrap());
+            let me = try!(modelthing::load_model_entry(dir));
+            println!("{}", try!(me.ast.repr_js()));
         },
         ("list", Some(subm)) => {
             let dir = Path::new(subm.value_of("DIR").unwrap_or("examples"));
@@ -90,7 +91,7 @@ fn main() {
         },
         ("load", Some(subm)) => {
             let dir = Path::new(subm.value_of("DIR").unwrap());
-            let me = modelthing::load_model_entry(dir).unwrap();
+            let me = try!(modelthing::load_model_entry(dir));
             println!("{:?}", me);
         },
         _ => {
@@ -99,4 +100,23 @@ fn main() {
             ::std::process::exit(-1);
         },
     }
+    Ok(())
+}
+
+fn main() {
+    if let Err(ref e) = run() {
+        println!("error: {}", e);
+
+        for e in e.iter().skip(1) {
+            println!("caused by: {}", e);
+        }
+
+        // The backtrace is not always generated. Try to run this example
+        // with `RUST_BACKTRACE=1`.
+        if let Some(backtrace) = e.backtrace() {
+            println!("backtrace: {:?}", backtrace);
+        }
+
+        ::std::process::exit(1);
+    }
 }
diff --git a/src/bin/mt-webface.rs b/src/bin/mt-webface.rs
index b35deec..4cdc509 100644
--- a/src/bin/mt-webface.rs
+++ b/src/bin/mt-webface.rs
@@ -15,6 +15,11 @@ use getopts::Options;
 use pencil::Pencil;
 use pencil::{Request, PencilResult, Response, HTTPError, PencilError};
 
+/*
+This command doesn't use error_chain (or raise errors in general) because the
+web framework handles panics as 500 errors automatically.
+*/
+
 
 fn home(r: &mut Request) -> PencilResult {
     let context: BTreeMap<String,String> = BTreeMap::new();