BLT editor: Basic BLT import functionality

html/blt/index.html

@@ -28,8 +28,8 @@
 			<input type="file" id="inpFile" style="display: none;" onchange="changeInpFile()">
 			<button onclick="clickOpenJSON()">Open JSON</button>
 			<button onclick="clickSaveJSON()">Save JSON</button>
-			<!--<button>Import BLT</button>
-			<button>Export BLT</button>-->
+			<button onclick="clickImportBLT()">Import BLT</button>
+			<!--<button>Export BLT</button>-->
 			<!--GITREV-->
 			<a href="https://yingtongli.me/blog/2020/12/24/pyrcv2.html">Information and instructions</a>
 		</div>
@@ -55,6 +55,7 @@
 			<div>Warning: Adding, removing or reordering candidates once ballots have been input may result in unexpected behaviour.</div>
 		</div>
 		
+		<script src="../bundle.js?v=GITVERSION"></script>
 		<script src="index.js?v=GITVERSION"></script>
 	</body>
 </html>

html/blt/index.js

@@ -106,13 +106,23 @@ function changeBallot() {
 	tblBallot.querySelector('input').select();
 }
 
+let openMode = 'json';
+
 function clickOpenJSON() {
+	openMode = 'json';
+	inpFile.value = '';
+	inpFile.click();
+}
+
+function clickImportBLT() {
+	openMode = 'blt';
 	inpFile.value = '';
 	inpFile.click();
 }
 
 async function changeInpFile() {
 	if (inpFile.value !== '') {
+		if (openMode === 'json') {
 			// Open JSON file
 			let text = await inpFile.files[0].text();
 			let obj = JSON.parse(text);
@@ -120,6 +130,35 @@ async function changeInpFile() {
 			// Load data
 			candidates = obj['candidates'];
 			ballots = obj['ballots'];
+		} else if (openMode === 'blt') {
+			// Open BLT file
+			let text = await inpFile.files[0].text();
+			
+			// Import data
+			py.pyRCV2.numbers.set_numclass(py.pyRCV2.numbers.StringNum);
+			let election = py.pyRCV2.blt.readBLT(text);
+			
+			candidates = [];
+			for (let candidate of election.candidates) {
+				candidates.push(candidate.py_name);
+			}
+			
+			ballots = [];
+			for (let ballot of election.ballots) {
+				let js_ballot = {'value': ballot.value.impl, 'preferences': []};
+				for (let i = 0; i < candidates.length; i++) {
+					js_ballot['preferences'].push('');
+				}
+				
+				// Add preference numbers
+				for (let i = 0; i < ballot.preferences.length; i++) {
+					candidate = ballot.preferences[i];
+					js_ballot['preferences'][election.candidates.indexOf(candidate)] = '' + (i + 1);
+				}
+				
+				ballots.push(js_ballot);
+			}
+		}
 		
 		// Update ballot entry
 		initBallot();
@@ -133,8 +172,9 @@ async function changeInpFile() {
 			elOption.innerText = 'Ballot ' + (i + 1);
 			selBallots.insertBefore(elOption, selBallots.selectedOptions[0]);
 		}
-	}
+		
 		inpFile.value = '';
+	}
 }
 
 function clickSaveJSON() {

pyRCV2/numbers/__init__.py

@@ -34,6 +34,7 @@ else: # pragma: no cover
 	from pyRCV2.numbers.gfixed_js import FixedGuarded, _gfixed_set_dps
 	from pyRCV2.numbers.native_js import Native
 	from pyRCV2.numbers.rational_js import Rational
+	from pyRCV2.numbers.string_js import StringNum
 
 # GLOBALS
 

pyRCV2/numbers/fixed_js.py

@@ -16,7 +16,11 @@
 
 from pyRCV2.numbers.base import BaseNum, compatible_types
 
-Big.DP = 6
+if __pragma__('js', '{}', 'typeof(bigInt)') != 'undefined':
+	Big.DP = 6
+else:
+	# Fail gracefully if dependencies not present
+	pass
 
 def _fixed_set_dps(dps):
 	Big.DP = dps

pyRCV2/numbers/gfixed_js.py

@@ -16,9 +16,13 @@
 
 from pyRCV2.numbers.base import BaseNum, compatible_types
 
-Big.DP = 12
-_pos_epsilon = Big('10').pow(-6).div('2')
-_neg_epsilon = _pos_epsilon.times('-1')
+if __pragma__('js', '{}', 'typeof(bigInt)') != 'undefined':
+	Big.DP = 12
+	_pos_epsilon = Big('10').pow(-6).div('2')
+	_neg_epsilon = _pos_epsilon.times('-1')
+else:
+	# Fail gracefully if dependencies not present
+	pass
 
 def _gfixed_set_dps(dps):
 	global _pos_epsilon, _neg_epsilon

pyRCV2/numbers/string_js.py

@@ -0,0 +1,28 @@
+#   pyRCV2: Preferential vote counting
+#   Copyright © 2020–2021  Lee Yingtong Li (RunasSudo)
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from pyRCV2.numbers.base import BaseNum
+
+class StringNum(BaseNum):
+	"""
+	Dummy class wrapping simple strings
+	Used when reading/writing BLTs with no arithmetic required - avoids loading dependencies
+	"""
+	
+	@classmethod
+	def _to_impl(cls, value):
+		"""Implements BaseNum._to_impl"""
+		return value

pyRCV2/random/sharandom_js.py

@@ -14,8 +14,14 @@
 #   You should have received a copy of the GNU Affero General Public License
 #   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+if __pragma__('js', '{}', 'typeof(bigInt)') != 'undefined':
+	_MAX_VAL = bigInt(2).pow(256).subtract(1)
+else:
+	# Fail gracefully if dependencies not present
+	_MAX_VAL = None
+
 class SHARandom:
-	MAX_VAL = bigInt(2).pow(256).subtract(1)
+	MAX_VAL = _MAX_VAL
 	
 	def __init__(self, seed):
 		self.seed = seed