Begin implementation of tie handling

build.sh

@@ -22,4 +22,4 @@ perl -0777 -i -pe 's#key \(a\) > key \(b\) \?#__gt__\(key \(a\), key \(b\)\) \?#
 rollup __target__/pyRCV2.transcrypt.js -o $OUTFILE --name py -f iife --no-treeshake || exit 1
 
 # Patch incorrectly generated iterator functions
-perl -0777 -i -pe "s#'__index0__'#__index0__#g" $OUTFILE || exit 1
+#perl -0777 -i -pe "s#'__index0__'#__index0__#g" $OUTFILE || exit 1

html/worker.js

@@ -49,6 +49,14 @@ onmessage = function(evt) {
 		counter = py.pyRCV2.method.base_stv.BaseWIGSTVCounter(election, evt.data.options);
 	}
 	
+	if (evt.data.options['ties'] === 'backwards_random') {
+		counter.options['ties'] = [py.pyRCV2.ties.TiesBackwards(), py.pyRCV2.ties.TiesRandom()];
+	} else if (evt.data.options['ties'] === 'random') {
+		counter.options['ties'] = [py.pyRCV2.ties.TiesRandom()];
+	} //else if (evt.data.options['ties'] === 'prompt') {
+	//	counter.options['ties'] = [py.pyRCV2.ties.TiesPrompt()];
+	//}
+	
 	// Reset
 	let result = counter.reset();
 	

pyRCV2/cli/stv.py

@@ -20,18 +20,20 @@ import pyRCV2.numbers
 
 from pyRCV2.method.base_stv import BaseUIGSTVCounter, BaseWIGSTVCounter
 from pyRCV2.method.wright import WrightSTVCounter
+from pyRCV2.ties import TiesBackwards, TiesPrompt, TiesRandom
 
 def add_parser(subparsers):
 	parser = subparsers.add_parser('stv', help='single transferable vote')
 	parser.add_argument('file', help='path to BLT file')
 	
 	parser.add_argument('--quota', '-q', choices=['droop', 'droop_exact', 'hare', 'hare_exact'], default='droop', help='quota calculation (default: droop)')
-	parser.add_argument('--quota-criterion', '-qc', choices=['geq', 'gt'], default='geq', help='quota criterion (default: geq)')
+	parser.add_argument('--quota-criterion', '-c', choices=['geq', 'gt'], default='geq', help='quota criterion (default: geq)')
 	parser.add_argument('--prog-quota', action='store_true', help='progressively reducing quota')
 	parser.add_argument('--numbers', '-n', choices=['fixed', 'rational', 'int', 'native'], default='fixed', help='numbers mode (default: fixed)')
 	parser.add_argument('--decimals', type=int, default=5, help='decimal places if --numbers fixed (default: 5)')
 	parser.add_argument('--surplus-order', '-s', choices=['size', 'order'], default='size', help='whether to distribute surpluses by size or by order of election (default: size)')
 	parser.add_argument('--method', '-m', choices=['wig', 'uig', 'wright'], default='wig', help='method of surpluses and exclusions (default: wig - weighted inclusive Gregory)')
+	parser.add_argument('--ties', '-t', action='append', choices=['backwards', 'prompt', 'random'], default=None, help='how to resolve ties (default: backwards then random)')
 
 def print_step(result):
 	print(result.comment)
@@ -80,6 +82,18 @@ def main(args):
 	else:
 		counter = BaseWIGSTVCounter(election, vars(args))
 	
+	if args.ties is None:
+		args.ties = ['backwards', 'random']
+	
+	counter.options['ties'] = []
+	for t in args.ties:
+		if t == 'backwards':
+			counter.options['ties'].append(TiesBackwards())
+		elif t == 'prompt':
+			counter.options['ties'].append(TiesPrompt())
+		elif t == 'random':
+			counter.options['ties'].append(TiesRandom())
+	
 	# Reset
 	result = counter.reset()
 	

pyRCV2/method/base_stv.py

@@ -19,6 +19,7 @@ __pragma__ = lambda x: None
 from pyRCV2.model import CandidateState, CountCard, CountCompleted, CountStepResult
 from pyRCV2.numbers import Num, Rational
 from pyRCV2.safedict import SafeDict
+from pyRCV2.ties import TiesBackwards, TiesPrompt, TiesRandom
 
 class STVException(Exception):
 	pass
@@ -39,6 +40,7 @@ class BaseSTVCounter:
 			'quota': 'droop', # 'droop', 'droop_exact', 'hare' or 'hare_exact'
 			'quota_criterion': 'geq', # 'geq' or 'gt'
 			'surplus_order': 'size', # 'size' or 'order'
+			'ties': [TiesBackwards(), TiesRandom()]
 		}
 		
 		if options is not None:
@@ -174,12 +176,13 @@ class BaseSTVCounter:
 			# Distribute surpluses in specified order
 			if self.options['surplus_order'] == 'size':
 				has_surplus.sort(key=lambda x: x[1].votes, reverse=True)
+				candidate_surplus, count_card = self.choose_highest(has_surplus) # May need to break ties
 			elif self.options['surplus_order'] == 'order':
 				has_surplus.sort(key=lambda x: x[1].order_elected)
+				candidate_surplus, count_card = has_surplus[0] # Ties were already broken when these were assigned
 			else:
 				raise STVException('Invalid surplus order option')
 			
-			candidate_surplus, count_card = has_surplus[0]
 			count_card.state = CandidateState.ELECTED
 			
 			__pragma__('opov')
@@ -253,8 +256,7 @@ class BaseSTVCounter:
 		hopefuls = [(c, cc) for c, cc in self.candidates.items() if cc.state == CandidateState.HOPEFUL]
 		hopefuls.sort(key=lambda x: x[1].votes)
 		
-		# TODO: Handle ties
-		candidate_excluded, count_card = hopefuls[0]
+		candidate_excluded, count_card = self.choose_lowest(hopefuls)
 		
 		return candidate_excluded, count_card
 	
@@ -312,11 +314,60 @@ class BaseSTVCounter:
 		meets_quota = [(c, cc) for c, cc in self.candidates.items() if cc.state == CandidateState.HOPEFUL and self.meets_quota(cc)]
 		
 		if len(meets_quota) > 0:
+			meets_quota.sort(key=lambda x: x[1].votes, reverse=True)
+			
 			# Declare elected any candidate who meets the quota
-			for candidate, count_card in meets_quota:
+			while len(meets_quota) > 0:
+				x = self.choose_highest(meets_quota)
+				candidate, count_card = x[0], x[1]
+				
 				count_card.state = CandidateState.PROVISIONALLY_ELECTED
 				count_card.order_elected = self.num_elected
 				self.num_elected += 1
+				
+				meets_quota.remove(x)
+	
+	def choose_lowest(self, l):
+		"""
+		Provided a list of tuples (Candidate, CountCard), sorted in ASCENDING order of votes, choose the tuple with the fewest votes, breaking ties appropriately
+		"""
+		
+		if len(l) == 1:
+			return l[0]
+		
+		tied = [(c, cc) for c, cc in l if cc.votes == l[0][1].votes]
+		
+		if len(tied) == 1:
+			return tied[0]
+		
+		# A tie exists
+		for tie in self.options['ties']:
+			result = tie.choose_lowest(tied)
+			if result is not None:
+				return result
+		
+		raise Exception('Unable to resolve tie')
+	
+	def choose_highest(self, l):
+		"""
+		Provided a list of tuples (Candidate, CountCard), sorted in DESCENDING order of votes, choose the tuple with the most votes, breaking ties appropriately
+		"""
+		
+		if len(l) == 1:
+			return l[0]
+		
+		tied = [(c, cc) for c, cc in l if cc.votes == l[0][1].votes]
+		
+		if len(tied) == 1:
+			return tied[0]
+		
+		# A tie exists
+		for tie in self.options['ties']:
+			result = tie.choose_highest(tied)
+			if result is not None:
+				return result
+		
+		raise Exception('Unable to resolve tie')
 
 class BaseWIGSTVCounter(BaseSTVCounter):
 	"""

pyRCV2/numbers/fixed_js.py

@@ -48,6 +48,8 @@ class Fixed:
 	def __div__(self, other):
 		return Fixed(self.impl.div(other.impl))
 	
+	def __eq__(self, other):
+		return self.impl.eq(other.impl)
 	def __gt__(self, other):
 		return self.impl.gt(other.impl)
 	def __ge__(self, other):

pyRCV2/numbers/fixed_py.py

@@ -52,6 +52,8 @@ class Fixed:
 	def __truediv__(self, other):
 		return Fixed(self.impl / other.impl)
 	
+	def __eq__(self, other):
+		return self.impl == other.impl
 	def __gt__(self, other):
 		return self.impl > other.impl
 	def __ge__(self, other):

pyRCV2/numbers/int_js.py

@@ -43,6 +43,8 @@ class NativeInt:
 	def __div__(self, other):
 		return NativeInt(self.impl / other.impl)
 	
+	def __eq__(self, other):
+		return self.impl == other.impl
 	def __gt__(self, other):
 		return self.impl > other.impl
 	def __ge__(self, other):

pyRCV2/numbers/int_py.py

@@ -45,6 +45,8 @@ class NativeInt:
 	def __truediv__(self, other):
 		return NativeInt(self.impl / other.impl)
 	
+	def __eq__(self, other):
+		return self.impl == other.impl
 	def __gt__(self, other):
 		return self.impl > other.impl
 	def __ge__(self, other):

pyRCV2/numbers/native_js.py

@@ -43,6 +43,8 @@ class Native:
 	def __div__(self, other):
 		return Native(self.impl / other.impl)
 	
+	def __eq__(self, other):
+		return self.impl == other.impl
 	def __gt__(self, other):
 		return self.impl > other.impl
 	def __ge__(self, other):

pyRCV2/numbers/native_py.py

@@ -45,6 +45,8 @@ class Native:
 	def __truediv__(self, other):
 		return Native(self.impl / other.impl)
 	
+	def __eq__(self, other):
+		return self.impl == other.impl
 	def __gt__(self, other):
 		return self.impl > other.impl
 	def __ge__(self, other):

pyRCV2/numbers/rational_js.py

@@ -53,6 +53,8 @@ class Rational:
 	def __div__(self, other):
 		return Rational(self.impl.divide(other.impl))
 	
+	def __eq__(self, other):
+		return self.impl.equals(other.impl)
 	def __gt__(self, other):
 		return self.impl.greater(other.impl)
 	def __ge__(self, other):

pyRCV2/numbers/rational_py.py

@@ -54,6 +54,8 @@ class Rational:
 	def __truediv__(self, other):
 		return Rational(self.impl / other.impl)
 	
+	def __eq__(self, other):
+		return self.impl == other.impl
 	def __gt__(self, other):
 		return self.impl > other.impl
 	def __ge__(self, other):

pyRCV2/ties.py

@@ -0,0 +1,78 @@
+#   pyRCV2: Preferential vote counting
+#   Copyright © 2020  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/>.
+
+__pragma__ = lambda x: None
+is_py = False
+__pragma__('skip')
+is_py = True
+__pragma__('noskip')
+
+class TiesPrompt:
+	"""Prompt the user to break ties"""
+	
+	def choose_lowest(self, l):
+		if is_py:
+			print('Multiple tied candidates:')
+			for i, x in enumerate(l):
+				print('{}. {}'.format(i + 1, x[0].name))
+			
+			while True:
+				choice = input('Which candidate to select? ')
+				try:
+					choice = int(choice)
+					if choice >= 1 and choice < len(l) + 1:
+						break
+				except ValueError:
+					pass
+			
+			print()
+			
+			return l[i - 1]
+		else:
+			# UNUSED IN JS - Cannot call window.prompt from Web Worker
+			# TODO: Work this out
+			message = ''
+			for i, x in enumerate(l):
+				message += (i + 1) + '. ' + x[0].name
+			message += 'Which candidate to select?'
+			
+			while True:
+				choice = window.prompt(message)
+				try:
+					choice = int(choice)
+					if choice >= 1 and choice < len(l) + 1:
+						break
+				except ValueError:
+					pass
+			
+			return l[i - 1]
+	
+	def choose_highest(self, l):
+		return self.choose_lowest(l)
+
+class TiesBackwards:
+	def choose_lowest(self, l):
+		raise Exception('Not yet implemented')
+	
+	def choose_highest(self, l):
+		raise Exception('Not yet implemented')
+
+class TiesRandom:
+	def choose_lowest(self, l):
+		raise Exception('Not yet implemented')
+	
+	def choose_highest(self, l):
+		raise Exception('Not yet implemented')

pyRCV2/transcrypt.py

@@ -18,5 +18,6 @@ import pyRCV2.blt
 import pyRCV2.model
 import pyRCV2.method, pyRCV2.method.base_stv, pyRCV2.method.wright
 import pyRCV2.numbers
+import pyRCV2.ties
 
 __pragma__('js', '{}', 'export {pyRCV2, isinstance, repr, str};')