Better error messages

build_wasm.sh

@@ -4,9 +4,9 @@ PATH=$PATH:$HOME/.cargo/bin
 # Build cargo
 PROFILE=${1:-release}
 if [ $PROFILE == 'debug' ]; then
-	cargo build --lib --target wasm32-unknown-unknown
+	cargo build --lib --target wasm32-unknown-unknown || exit 1
 else
-	cargo build --lib --target wasm32-unknown-unknown --$PROFILE
+	cargo build --lib --target wasm32-unknown-unknown --$PROFILE || exit 1
 fi
 
 # Apply wasm-bindgen

html/index.js

@@ -97,6 +97,9 @@ worker.onmessage = function(evt) {
 			response = window.prompt(evt.data.message);
 		}
 		worker.postMessage({'type': 'userInput', 'response': response});
+		
+	} else if (evt.data.type === 'errorMessage') {
+		divLogs2.insertAdjacentHTML('beforeend', evt.data.message);
 	}
 }
 
@@ -155,6 +158,9 @@ async function clickCount() {
 		parseInt(document.getElementById('txtPPDP').value),
 	];
 	
+	// Reset UI
+	document.getElementById('printPane').style.display = 'none';
+	divLogs2.innerHTML = ''; // Might have error messages from previous execution
 	
 	// Dispatch to worker
 	worker.postMessage({

html/worker.js

@@ -20,7 +20,10 @@ initWasm();
 var numbers, election, opts, state, stageNum;
 
 onmessage = function(evt) {
+	try {
 		if (evt.data.type === 'countElection') {
+			errored = false;
+			
 			if (evt.data.numbers === 'fixed') {
 				numbers = 'Fixed';
 				wasm.fixed_set_dps(evt.data.decimals);
@@ -78,6 +81,13 @@ onmessage = function(evt) {
 			wasmRaw.asyncify_start_rewind(DATA_ADDR);
 			resumeCount();
 		}
+	} catch (ex) {
+		if (errored) {
+			// Panic already logged and sent to UI
+		} else {
+			throw ex;
+		}
+	}
 }
 
 function resumeCount() {
@@ -102,6 +112,12 @@ function resumeCount() {
 	postMessage({'type': 'finalResultSummary', 'summary': wasm['final_result_summary_' + numbers](state, opts)});
 }
 
+var errored = false;
+function wasm_error(message) {
+	postMessage({'type': 'errorMessage', 'message': message});
+	errored = true;
+}
+
 var userInputBuffer = null;
 
 function get_user_input(message) {

src/election.rs

@@ -18,12 +18,21 @@
 use crate::constraints::{Constraints, ConstraintMatrix};
 use crate::logger::Logger;
 use crate::numbers::Number;
-use crate::parser::blt::BLTParser;
+use crate::parser::blt::{BLTParser, ParseError};
 use crate::sharandom::SHARandom;
 
 use std::collections::HashMap;
 use std::iter::Peekable;
 
+#[cfg(not(target_arch = "wasm32"))]
+use utf8_chars::BufReadCharsExt;
+#[cfg(not(target_arch = "wasm32"))]
+use std::fs::File;
+#[cfg(not(target_arch = "wasm32"))]
+use std::io::BufReader;
+#[cfg(not(target_arch = "wasm32"))]
+use std::path::Path;
+
 /// An election to be counted
 pub struct Election<N> {
 	/// Name of the election
@@ -42,12 +51,18 @@ pub struct Election<N> {
 
 impl<N: Number> Election<N> {
 	/// Parse the given BLT file and return an [Election]
-	pub fn from_blt<I: Iterator<Item=char>>(input: Peekable<I>) -> Self {
+	pub fn from_blt<I: Iterator<Item=char>>(input: Peekable<I>) -> Result<Self, ParseError> {
 		let mut parser = BLTParser::new(input);
-		match parser.parse_blt() {
+		parser.parse_blt()?;
-			Ok(_) => { return parser.as_election(); }
+		return Ok(parser.as_election());
-			Err(e) => { panic!("Syntax Error: {}", e); }
 	}
+	
+	/// Parse the BLT file at the given path and return an [Election]
+	#[cfg(not(target_arch = "wasm32"))]
+	pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Self, ParseError> {
+		let mut reader = BufReader::new(File::open(path).expect("IO Error"));
+		let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
+		return Ok(Election::from_blt(chars)?);
 	}
 	
 	/// Convert ballots with weight >1 to multiple ballots of weight 1

src/main.rs

@@ -21,11 +21,10 @@ use opentally::numbers::{Fixed, GuardedFixed, NativeFloat64, Number, Rational};
 use opentally::stv;
 
 use clap::{AppSettings, Clap};
-use utf8_chars::BufReadCharsExt;
 
 use std::cmp::max;
 use std::fs::File;
-use std::io::{self, BufRead, BufReader};
+use std::io::{self, BufRead};
 use std::ops;
 
 /// Open-source election vote counting
@@ -186,36 +185,54 @@ struct STV {
 }
 
 fn main() {
+	match main_() {
+		Ok(_) => {}
+		Err(code) => {
+			std::process::exit(code);
+		}
+	}
+}
+
+fn main_() -> Result<(), i32> {
 	// Read arguments
 	let opts: Opts = Opts::parse();
 	let Command::STV(cmd_opts) = opts.command;
 	
-	// Read BLT file
+	// Read and count election according to --numbers
-	let mut reader = BufReader::new(File::open(&cmd_opts.filename).expect("IO Error"));
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	
-	// Create and count election according to --numbers
 	if cmd_opts.numbers == "rational" {
-		let mut election: Election<Rational> = Election::from_blt(chars);
+		let mut election = election_from_file(&cmd_opts.filename)?;
 		maybe_load_constraints(&mut election, &cmd_opts.constraints);
 		
 		// Must specify ::<N> here and in a few other places because ndarray causes E0275 otherwise
-		count_election::<Rational>(election, cmd_opts);
+		count_election::<Rational>(election, cmd_opts)?;
 	} else if cmd_opts.numbers == "float64" {
-		let mut election: Election<NativeFloat64> = Election::from_blt(chars);
+		let mut election = election_from_file(&cmd_opts.filename)?;
 		maybe_load_constraints(&mut election, &cmd_opts.constraints);
-		count_election::<NativeFloat64>(election, cmd_opts);
+		count_election::<NativeFloat64>(election, cmd_opts)?;
 	} else if cmd_opts.numbers == "fixed" {
 		Fixed::set_dps(cmd_opts.decimals);
-		let mut election: Election<Fixed> = Election::from_blt(chars);
+		
+		let mut election = election_from_file(&cmd_opts.filename)?;
 		maybe_load_constraints(&mut election, &cmd_opts.constraints);
-		count_election::<Fixed>(election, cmd_opts);
+		count_election::<Fixed>(election, cmd_opts)?;
 	} else if cmd_opts.numbers == "gfixed" {
 		GuardedFixed::set_dps(cmd_opts.decimals);
 		
-		let mut election: Election<GuardedFixed> = Election::from_blt(chars);
+		let mut election = election_from_file(&cmd_opts.filename)?;
 		maybe_load_constraints(&mut election, &cmd_opts.constraints);
-		count_election::<GuardedFixed>(election, cmd_opts);
+		count_election::<GuardedFixed>(election, cmd_opts)?;
+	}
+	
+	return Ok(());
+}
+
+fn election_from_file<N: Number>(path: &str) -> Result<Election<N>, i32> {
+	match Election::from_file(path) {
+		Ok(e) => return Ok(e),
+		Err(err) => {
+			println!("Syntax Error: {}", err);
+			return Err(1);
+		}
 	}
 }
 
@@ -227,7 +244,7 @@ fn maybe_load_constraints<N: Number>(election: &mut Election<N>, constraints: &O
 	}
 }
 
-fn count_election<N: Number>(mut election: Election<N>, cmd_opts: STV)
+fn count_election<N: Number>(mut election: Election<N>, cmd_opts: STV) -> Result<(), i32>
 where
 	for<'r> &'r N: ops::Sub<&'r N, Output=N>,
 	for<'r> &'r N: ops::Mul<&'r N, Output=N>,
@@ -263,7 +280,13 @@ where
 	);
 	
 	// Validate options
-	stv_opts.validate();
+	match stv_opts.validate() {
+		Ok(_) => {}
+		Err(err) => {
+			println!("Error: {}", err.describe());
+			return Err(1);
+		}
+	}
 	
 	// Describe count
 	let total_ballots = election.ballots.iter().fold(N::zero(), |acc, b| { acc + &b.orig_value });
@@ -285,15 +308,30 @@ where
 	let mut state = CountState::new(&election);
 	
 	// Distribute first preferences
-	stv::count_init(&mut state, &stv_opts).unwrap();
+	match stv::count_init(&mut state, &stv_opts) {
+		Ok(_) => {}
+		Err(err) => {
+			println!("Error: {}", err.describe());
+			return Err(1);
+		}
+	}
+	
 	let mut stage_num = 1;
 	print_stage(stage_num, &state, &cmd_opts);
 	
 	loop {
-		let is_done = stv::count_one_stage(&mut state, &stv_opts);
+		match stv::count_one_stage(&mut state, &stv_opts) {
-		if is_done.unwrap() {
+			Ok(is_done) => {
+				if is_done {
 					break;
 				}
+			}
+			Err(err) => {
+				println!("Error: {}", err.describe());
+				return Err(1);
+			}
+		}
+		
 		stage_num += 1;
 		print_stage(stage_num, &state, &cmd_opts);
 	}
@@ -315,6 +353,8 @@ where
 			println!("{}. {}", i + 1, winner.name);
 		}
 	}
+	
+	return Ok(());
 }
 
 fn print_candidates<'a, N: 'a + Number, I: Iterator<Item=(&'a Candidate, &'a CountCard<'a, N>)>>(candidates: I, cmd_opts: &STV) {

src/parser/blt.rs

@@ -61,6 +61,12 @@ impl fmt::Display for ParseError {
 	}
 }
 
+impl fmt::Debug for ParseError {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		return fmt::Display::fmt(self, f);
+	}
+}
+
 impl<N: Number, I: Iterator<Item=char>> BLTParser<N, I> {
 	// NON-TERMINALS - HIGHER LEVEL
 	

src/stv/mod.rs

@@ -36,6 +36,7 @@ use itertools::Itertools;
 use wasm_bindgen::prelude::wasm_bindgen;
 
 use std::collections::HashMap;
+use std::fmt;
 use std::ops;
 
 /// Options for conducting an STV count
@@ -228,11 +229,12 @@ impl STVOptions {
 	}
 	
 	/// Validate the combination of [STVOptions] and panic if invalid
-	pub fn validate(&self) {
+	pub fn validate(&self) -> Result<(), STVError> {
 		if self.surplus == SurplusMethod::Meek {
-			if self.transferable_only { panic!("--surplus meek is incompatible with --transferable-only"); }
+			if self.transferable_only { return Err(STVError::InvalidOptions("--surplus meek is incompatible with --transferable-only")); }
-			if self.exclusion != ExclusionMethod::SingleStage { panic!("--surplus meek requires --exclusion single_stage"); }
+			if self.exclusion != ExclusionMethod::SingleStage { return Err(STVError::InvalidOptions("--surplus meek requires --exclusion single_stage")); }
 		}
+		return Ok(());
 	}
 }
 
@@ -431,25 +433,31 @@ impl ConstraintMode {
 }
 
 /// An error during the STV count
-#[wasm_bindgen]
 #[derive(Debug)]
 pub enum STVError {
-	/// User input is required
+	/// Options for the count are invalid
-	RequireInput,
+	InvalidOptions(&'static str),
 	/// Tie could not be resolved
 	UnresolvedTie,
 }
 
 impl STVError {
-	/// Return the name of the error as a string
+	/// Describe the error
-	pub fn name(&self) -> &'static str {
+	pub fn describe(&self) -> &'static str {
 		match self {
-			STVError::RequireInput => "RequireInput",
+			STVError::InvalidOptions(s) => s,
-			STVError::UnresolvedTie => "UnresolvedTie",
+			STVError::UnresolvedTie => "Unable to resolve tie",
 		}
 	}
 }
 
+impl fmt::Display for STVError {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.write_str(self.describe())?;
+		return Ok(());
+	}
+}
+
 /// Distribute first preferences, and initialise other states such as the random number generator and tie-breaking rules
 pub fn count_init<'a, N: Number>(state: &mut CountState<'a, N>, opts: &'a STVOptions) -> Result<bool, STVError>
 where
@@ -1288,7 +1296,7 @@ fn choose_highest<'c, N: Number>(state: &mut CountState<N>, opts: &STVOptions, c
 			}
 		}
 	}
-	panic!("Unable to resolve tie");
+	return Err(STVError::UnresolvedTie);
 }
 
 /// Break a tie between the given candidates according to [STVOptions::ties], selecting the lowest candidate
@@ -1309,7 +1317,7 @@ fn choose_lowest<'c, N: Number>(state: &mut CountState<N>, opts: &STVOptions, ca
 			}
 		}
 	}
-	panic!("Unable to resolve tie");
+	return Err(STVError::UnresolvedTie);
 }
 
 /// If required, initialise the state of the forwards or backwards tie-breaking strategies, according to [STVOptions::ties]

src/stv/wasm.rs

@@ -16,6 +16,7 @@
  */
 
 #![allow(rustdoc::private_intra_doc_links)]
+#![allow(unused_unsafe)] // Confuses cargo check
 
 use crate::constraints::Constraints;
 use crate::election::{CandidateState, CountState, Election};
@@ -25,10 +26,24 @@ use crate::stv;
 extern crate console_error_panic_hook;
 
 use js_sys::Array;
-use wasm_bindgen::{JsValue, prelude::wasm_bindgen};
+use wasm_bindgen::prelude::wasm_bindgen;
 
 use std::cmp::max;
 
+// Error handling
+
+#[wasm_bindgen]
+extern "C" {
+	fn wasm_error(message: String);
+}
+
+macro_rules! wasm_error {
+	($type:expr, $err:expr) => { {
+		unsafe { wasm_error(format!("{}: {}", $type, $err)); }
+		panic!("{}: {}", $type, $err);
+	} }
+}
+
 // Init
 
 /// Wrapper for [Fixed::set_dps]
@@ -56,7 +71,10 @@ macro_rules! impl_type {
 			// Install panic! hook
 			console_error_panic_hook::set_once();
 			
-			let election: Election<$type> = Election::from_blt(text.chars().peekable());
+			let election: Election<$type> = match Election::from_blt(text.chars().peekable()) {
+				Ok(e) => e,
+				Err(err) => wasm_error!("Syntax Error", err),
+			};
 			return [<Election$type>](election);
 		}
 		
@@ -77,20 +95,20 @@ macro_rules! impl_type {
 		/// Wrapper for [stv::count_init]
 		#[wasm_bindgen]
 		#[allow(non_snake_case)]
-		pub fn [<count_init_$type>](state: &mut [<CountState$type>], opts: &STVOptions) -> Result<bool, JsValue> {
+		pub fn [<count_init_$type>](state: &mut [<CountState$type>], opts: &STVOptions) -> bool {
 			match stv::count_init(&mut state.0, opts.as_static()) {
-				Ok(v) => Ok(v),
+				Ok(v) => v,
-				Err(e) => Err(e.name().into()),
+				Err(err) => wasm_error!("Error", err),
 			}
 		}
 		
 		/// Wrapper for [stv::count_one_stage]
 		#[wasm_bindgen]
 		#[allow(non_snake_case)]
-		pub fn [<count_one_stage_$type>](state: &mut [<CountState$type>], opts: &STVOptions) -> Result<bool, JsValue> {
+		pub fn [<count_one_stage_$type>](state: &mut [<CountState$type>], opts: &STVOptions) -> bool {
 			match stv::count_one_stage::<[<$type>]>(&mut state.0, &opts.0) {
-				Ok(v) => Ok(v),
+				Ok(v) => v,
-				Err(e) => Err(e.name().into()),
+				Err(err) => wasm_error!("Error", err),
 			}
 		}
 		
@@ -248,7 +266,10 @@ impl STVOptions {
 	
 	/// Wrapper for [stv::STVOptions::validate]
 	pub fn validate(&self) {
-		self.0.validate();
+		match self.0.validate() {
+			Ok(_) => {}
+			Err(err) => { wasm_error!("Error", err) }
+		}
 	}
 }
 

tests/aec.rs

@@ -52,7 +52,7 @@ fn aec_tas19_rational() {
 	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
 	
 	// Read BLT
-	let election: Election<Rational> = Election::from_blt(chars);
+	let election: Election<Rational> = Election::from_blt(chars).expect("Syntax Error");
 	
 	// Validate candidate names
 	for (i, candidate) in candidates.iter().enumerate() {

tests/constraints.rs

@@ -21,19 +21,16 @@ use opentally::constraints::Constraints;
 use opentally::election::{CandidateState, CountState, Election};
 use opentally::numbers::Rational;
 use opentally::stv;
-use utf8_chars::BufReadCharsExt;
 
 use std::fs::File;
-use std::io::{self, BufRead, BufReader}; 
+use std::io::{self, BufRead}; 
 
 #[test]
 fn prsa1_constr1_rational() {
 	// FIXME: This is unvalidated!
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open("tests/data/prsa1.blt").expect("IO Error"));
+	let mut election: Election<Rational> = Election::from_file("tests/data/prsa1.blt").expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	let mut election: Election<Rational> = Election::from_blt(chars);
 	
 	// Read CON
 	let file = File::open("tests/data/prsa1_constr1.con").expect("IO Error");
@@ -94,9 +91,7 @@ fn prsa1_constr2_rational() {
 	// FIXME: This is unvalidated!
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open("tests/data/prsa1.blt").expect("IO Error"));
+	let mut election: Election<Rational> = Election::from_file("tests/data/prsa1.blt").expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	let mut election: Election<Rational> = Election::from_blt(chars);
 	
 	// Read CON
 	let file = File::open("tests/data/prsa1_constr2.con").expect("IO Error");
@@ -157,9 +152,7 @@ fn prsa1_constr3_rational() {
 	// FIXME: This is unvalidated!
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open("tests/data/prsa1.blt").expect("IO Error"));
+	let mut election: Election<Rational> = Election::from_file("tests/data/prsa1.blt").expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	let mut election: Election<Rational> = Election::from_blt(chars);
 	
 	// Read CON
 	let file = File::open("tests/data/prsa1_constr3.con").expect("IO Error");

tests/meek.rs

@@ -87,9 +87,7 @@ fn meek06_ers97_fixed12() {
 	Fixed::set_dps(12);
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open("tests/data/ers97.blt").expect("IO Error"));
+	let election: Election<Fixed> = Election::from_file("tests/data/ers97.blt").expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	let election: Election<Fixed> = Election::from_blt(chars);
 	
 	// Initialise count state
 	let mut state = CountState::new(&election);
@@ -161,9 +159,7 @@ fn meeknz_ers97_fixed12() {
 	Fixed::set_dps(12);
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open("tests/data/ers97.blt").expect("IO Error"));
+	let election: Election<Fixed> = Election::from_file("tests/data/ers97.blt").expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	let election: Election<Fixed> = Election::from_blt(chars);
 	
 	// Initialise count state
 	let mut state = CountState::new(&election);

tests/scotland.rs

@@ -113,9 +113,7 @@ where
 	let num_stages = root.get_child("headerrow").expect("Syntax Error").children.len();
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open("tests/data/linn07.blt").expect("IO Error"));
+	let mut election: Election<N> = Election::from_file("tests/data/linn07.blt").expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	let mut election: Election<N> = Election::from_blt(chars);
 	
 	// !!! FOR SCOTTISH STV !!!
 	election.normalise_ballots();

tests/utils/mod.rs

@@ -20,10 +20,7 @@ use opentally::numbers::Number;
 use opentally::stv;
 
 use csv::StringRecord;
-use utf8_chars::BufReadCharsExt;
 
-use std::fs::File;
-use std::io::BufReader;
 use std::ops;
 
 #[allow(dead_code)] // Suppress false positive
@@ -49,10 +46,7 @@ where
 	let stages: Vec<usize> = records.first().unwrap().iter().skip(1).step_by(2).map(|s| s.parse().unwrap()).collect();
 	
 	// Read BLT
-	let mut reader = BufReader::new(File::open(blt_file).expect("IO Error"));
+	let election: Election<N> = Election::from_file(blt_file).expect("Syntax Error");
-	let chars = reader.chars().map(|r| r.expect("IO Error")).peekable();
-	
-	let election: Election<N> = Election::from_blt(chars);
 	
 	// Validate candidate names
 	for (i, candidate) in candidates.iter().enumerate() {