Move model parameter parsing out of main

fj-app/src/args.rs

@@ -1,5 +1,7 @@
 use std::{path::PathBuf, str::FromStr as _};
 
+use anyhow::anyhow;
+use fj_host::Parameters;
 use fj_kernel::algorithms::Tolerance;
 use fj_math::Scalar;
 
@@ -15,8 +17,8 @@ pub struct Args {
     pub export: Option<PathBuf>,
 
     /// Parameters for the model, each in the form `key=value`
-    #[clap(short, long)]
+    #[clap(short, long, parse(try_from_str = parse_parameters))]
-    pub parameters: Vec<String>,
+    pub parameters: Option<Parameters>,
 
     /// Model deviation tolerance
     #[clap[short, long, parse(try_from_str = parse_tolerance)]]
@@ -33,6 +35,27 @@ impl Args {
     }
 }
 
+fn parse_parameters(input: &str) -> anyhow::Result<Parameters> {
+    let mut parameters = Parameters::empty();
+
+    for parameter in input.split(',') {
+        let mut parameter = parameter.splitn(2, '=');
+
+        let key = parameter
+            .next()
+            .ok_or_else(|| anyhow!("Expected model parameter key"))?
+            .to_owned();
+        let value = parameter
+            .next()
+            .ok_or_else(|| anyhow!("Expected model parameter value"))?
+            .to_owned();
+
+        parameters.0.insert(key, value);
+    }
+
+    Ok(parameters)
+}
+
 fn parse_tolerance(input: &str) -> anyhow::Result<Tolerance> {
     let tolerance = f64::from_str(input)?;
     let tolerance = Scalar::from_f64(tolerance);

fj-app/src/main.rs

@@ -6,7 +6,7 @@ mod input;
 mod window;
 
 use std::path::PathBuf;
-use std::{collections::HashMap, time::Instant};
+use std::time::Instant;
 
 use fj_host::{Model, Parameters};
 use fj_interop::{debug::DebugInfo, mesh::Mesh};
@@ -61,29 +61,14 @@ fn main() -> anyhow::Result<()> {
     }
 
     let model = Model::from_path(path, config.target_dir)?;
-
+    let parameters = args.parameters.unwrap_or_else(Parameters::empty);
-    let mut parameters = HashMap::new();
-    for parameter in args.parameters {
-        let mut parameter = parameter.splitn(2, '=');
-
-        let key = parameter
-            .next()
-            .expect("model parameter: key not found")
-            .to_owned();
-        let value = parameter
-            .next()
-            .expect("model parameter: value not found")
-            .to_owned();
-
-        parameters.insert(key, value);
-    }
 
     let shape_processor = ShapeProcessor {
         tolerance: args.tolerance,
     };
 
     if let Some(path) = args.export {
-        let shape = model.load_once(&Parameters(parameters))?;
+        let shape = model.load_once(&parameters)?;
         let shape = shape_processor.process(&shape);
 
         let vertices =
@@ -111,7 +96,7 @@ fn main() -> anyhow::Result<()> {
         return Ok(());
     }
 
-    let watcher = model.load_and_watch(Parameters(parameters))?;
+    let watcher = model.load_and_watch(parameters)?;
 
     let event_loop = EventLoop::new();
     let window = Window::new(&event_loop);