fix: Rework of all Hash() and Equals() methods - implement generic collections

 - Implement new collections using generics that implement the functionality
   required by the Java runtime in a more idiomatic Go way.
 - Fix Hash() and Equals() for all objects in the runtime
 - Fix getConflictingAlts so that it behaves the same way as Java, using a
   new generic collection
 - Replaces the use of the array2DHashSet, which was causing unneeded memory
   allocations. Replaced with generic collection that allocates minimally
   (though, I think I can improve on that with a little analysis).

Jim Idle - [email protected]

Signed-off-by: Jim.Idle <[email protected]>

Author: Jim.Idle

runtime/Go/antlr/atn_config.go

@@ -8,21 +8,14 @@ import (
 	"fmt"
 )
 
-type comparable interface {
-	equals(other interface{}) bool
-}
-
 // ATNConfig is a tuple: (ATN state, predicted alt, syntactic, semantic
 // context). The syntactic context is a graph-structured stack node whose
 // path(s) to the root is the rule invocation(s) chain used to arrive at the
 // state. The semantic context is the tree of semantic predicates encountered
 // before reaching an ATN state.
 type ATNConfig interface {
-	comparable
-
-	gequals(other Collectable[ATNConfig]) bool
-
-	hash() int
+	Equals(o Collectable[ATNConfig]) bool
+	Hash() int
 
 	GetState() ATNState
 	GetAlt() int
@@ -136,15 +129,17 @@ func (b *BaseATNConfig) GetReachesIntoOuterContext() int {
 func (b *BaseATNConfig) SetReachesIntoOuterContext(v int) {
 	b.reachesIntoOuterContext = v
 }
-func (b *BaseATNConfig) equals(o interface{}) bool {
-	return b.gequals(o.(Collectable[ATNConfig]))
-}
 
+// Equals is the default comparison function for an ATNConfig when no specialist implementation is required
+// for a collection.
+//
 // An ATN configuration is equal to another if both have the same state, they
 // predict the same alternative, and syntactic/semantic contexts are the same.
-func (b *BaseATNConfig) gequals(o Collectable[ATNConfig]) bool {
+func (b *BaseATNConfig) Equals(o Collectable[ATNConfig]) bool {
 	if b == o {
 		return true
+	} else if o == nil {
+		return false
 	}
 
 	var other, ok = o.(*BaseATNConfig)
@@ -158,30 +153,32 @@ func (b *BaseATNConfig) gequals(o Collectable[ATNConfig]) bool {
 	if b.context == nil {
 		equal = other.context == nil
 	} else {
-		equal = b.context.gequals(other.context)
+		equal = b.context.Equals(other.context)
 	}
 
 	var (
 		nums = b.state.GetStateNumber() == other.state.GetStateNumber()
 		alts = b.alt == other.alt
-		cons = b.semanticContext.equals(other.semanticContext)
+		cons = b.semanticContext.Equals(other.semanticContext)
 		sups = b.precedenceFilterSuppressed == other.precedenceFilterSuppressed
 	)
 
 	return nums && alts && cons && sups && equal
 }
 
-func (b *BaseATNConfig) hash() int {
+// Hash is the default hash function for BaseATNConfig, when no specialist hash function
+// is required for a collection
+func (b *BaseATNConfig) Hash() int {
 	var c int
 	if b.context != nil {
-		c = b.context.hash()
+		c = b.context.Hash()
 	}
 
 	h := murmurInit(7)
 	h = murmurUpdate(h, b.state.GetStateNumber())
 	h = murmurUpdate(h, b.alt)
 	h = murmurUpdate(h, c)
-	h = murmurUpdate(h, b.semanticContext.hash())
+	h = murmurUpdate(h, b.semanticContext.Hash())
 	return murmurFinish(h, 4)
 }
 
@@ -248,7 +245,9 @@ func NewLexerATNConfig1(state ATNState, alt int, context PredictionContext) *Lex
 	return &LexerATNConfig{BaseATNConfig: NewBaseATNConfig5(state, alt, context, SemanticContextNone)}
 }
 
-func (l *LexerATNConfig) hash() int {
+// Hash is the default hash function for LexerATNConfig objects, it can be used directly or via
+// the default comparator [ObjEqComparator].
+func (l *LexerATNConfig) Hash() int {
 	var f int
 	if l.passedThroughNonGreedyDecision {
 		f = 1
@@ -258,19 +257,20 @@ func (l *LexerATNConfig) hash() int {
 	h := murmurInit(7)
 	h = murmurUpdate(h, l.state.GetStateNumber())
 	h = murmurUpdate(h, l.alt)
-	h = murmurUpdate(h, l.context.hash())
-	h = murmurUpdate(h, l.semanticContext.hash())
+	h = murmurUpdate(h, l.context.Hash())
+	h = murmurUpdate(h, l.semanticContext.Hash())
 	h = murmurUpdate(h, f)
-	h = murmurUpdate(h, l.lexerActionExecutor.hash())
+	h = murmurUpdate(h, l.lexerActionExecutor.Hash())
 	h = murmurFinish(h, 6)
 	return h
 }
 
-func (l *LexerATNConfig) equals(other interface{}) bool {
-	return l.gequals(other.(Collectable[ATNConfig]))
-}
-
-func (l *LexerATNConfig) gequals(other Collectable[ATNConfig]) bool {
+// Equals is the default comparison function for LexerATNConfig objects, it can be used directly or via
+// the default comparator [ObjEqComparator].
+func (l *LexerATNConfig) Equals(other Collectable[ATNConfig]) bool {
+	if l == other {
+		return true
+	}
 	var othert, ok = other.(*LexerATNConfig)
 
 	if l == other {
@@ -284,7 +284,7 @@ func (l *LexerATNConfig) gequals(other Collectable[ATNConfig]) bool {
 	var b bool
 
 	if l.lexerActionExecutor != nil {
-		b = !l.lexerActionExecutor.equals(othert.lexerActionExecutor)
+		b = !l.lexerActionExecutor.Equals(othert.lexerActionExecutor)
 	} else {
 		b = othert.lexerActionExecutor != nil
 	}
@@ -293,7 +293,7 @@ func (l *LexerATNConfig) gequals(other Collectable[ATNConfig]) bool {
 		return false
 	}
 
-	return l.BaseATNConfig.equals(othert.BaseATNConfig)
+	return l.BaseATNConfig.Equals(othert.BaseATNConfig)
 }
 
 func checkNonGreedyDecision(source *LexerATNConfig, target ATNState) bool {

runtime/Go/antlr/atn_config_set.go

@@ -7,18 +7,17 @@ package antlr
 import "fmt"
 
 type ATNConfigSet interface {
-	hash() int
+	Hash() int
+	Equals(o Collectable[ATNConfig]) bool
 	Add(ATNConfig, *DoubleDict) bool
 	AddAll([]ATNConfig) bool
 
-	GetStates() Set
+	GetStates() *JStore[ATNState, Comparator[ATNState]]
 	GetPredicates() []SemanticContext
 	GetItems() []ATNConfig
 
 	OptimizeConfigs(interpreter *BaseATNSimulator)
 
-	Equals(other interface{}) bool
-
 	Length() int
 	IsEmpty() bool
 	Contains(ATNConfig) bool
@@ -57,7 +56,7 @@ type BaseATNConfigSet struct {
 	// effectively doubles the number of objects associated with ATNConfigs. All
 	// keys are hashed by (s, i, _, pi), not including the context. Wiped out when
 	// read-only because a set becomes a DFA state.
-	configLookup Set
+	configLookup *JStore[ATNConfig, Comparator[ATNConfig]]
 
 	// configs is the added elements.
 	configs []ATNConfig
@@ -83,7 +82,7 @@ type BaseATNConfigSet struct {
 
 	// readOnly is whether it is read-only. Do not
 	// allow any code to manipulate the set if true because DFA states will point at
-	// sets and those must not change. It not protect other fields; conflictingAlts
+	// sets and those must not change. It not, protect other fields; conflictingAlts
 	// in particular, which is assigned after readOnly.
 	readOnly bool
 
@@ -104,7 +103,7 @@ func (b *BaseATNConfigSet) Alts() *BitSet {
 func NewBaseATNConfigSet(fullCtx bool) *BaseATNConfigSet {
 	return &BaseATNConfigSet{
 		cachedHash:   -1,
-		configLookup: newArray2DHashSetWithCap(hashATNConfig, equalATNConfigs, 16, 2),
+		configLookup: NewJStore[ATNConfig, Comparator[ATNConfig]](&ATNConfigComparator[ATNConfig]{}),
 		fullCtx:      fullCtx,
 	}
 }
@@ -126,9 +125,11 @@ func (b *BaseATNConfigSet) Add(config ATNConfig, mergeCache *DoubleDict) bool {
 		b.dipsIntoOuterContext = true
 	}
 
-	existing := b.configLookup.Add(config).(ATNConfig)
+	existing, present := b.configLookup.Put(config)
 
-	if existing == config {
+	// The config was not already in the set
+	//
+	if !present {
 		b.cachedHash = -1
 		b.configs = append(b.configs, config) // Track order here
 		return true
@@ -154,11 +155,14 @@ func (b *BaseATNConfigSet) Add(config ATNConfig, mergeCache *DoubleDict) bool {
 	return true
 }
 
-func (b *BaseATNConfigSet) GetStates() Set {
-	states := newArray2DHashSet(nil, nil)
+func (b *BaseATNConfigSet) GetStates() *JStore[ATNState, Comparator[ATNState]] {
+
+	// states uses the standard comparator provided by the ATNState instance
+	//
+	states := NewJStore[ATNState, Comparator[ATNState]](&ObjEqComparator[ATNState]{})
 
 	for i := 0; i < len(b.configs); i++ {
-		states.Add(b.configs[i].GetState())
+		states.Put(b.configs[i].GetState())
 	}
 
 	return states
@@ -227,7 +231,7 @@ func (b *BaseATNConfigSet) Compare(bs *BaseATNConfigSet) bool {
 	for _, c := range b.configs {
 		found := false
 		for _, c2 := range bs.configs {
-			if c.equals(c2) {
+			if c.Equals(c2) {
 				found = true
 				break
 			}
@@ -241,7 +245,7 @@ func (b *BaseATNConfigSet) Compare(bs *BaseATNConfigSet) bool {
 	return true
 }
 
-func (b *BaseATNConfigSet) Equals(other interface{}) bool {
+func (b *BaseATNConfigSet) Equals(other Collectable[ATNConfig]) bool {
 	if b == other {
 		return true
 	} else if _, ok := other.(*BaseATNConfigSet); !ok {
@@ -259,7 +263,7 @@ func (b *BaseATNConfigSet) Equals(other interface{}) bool {
 		b.Compare(other2)
 }
 
-func (b *BaseATNConfigSet) hash() int {
+func (b *BaseATNConfigSet) Hash() int {
 	if b.readOnly {
 		if b.cachedHash == -1 {
 			b.cachedHash = b.hashCodeConfigs()
@@ -274,7 +278,7 @@ func (b *BaseATNConfigSet) hash() int {
 func (b *BaseATNConfigSet) hashCodeConfigs() int {
 	h := 1
 	for _, config := range b.configs {
-		h = 31*h + config.hash()
+		h = 31*h + config.Hash()
 	}
 	return h
 }
@@ -310,7 +314,7 @@ func (b *BaseATNConfigSet) Clear() {
 
 	b.configs = make([]ATNConfig, 0)
 	b.cachedHash = -1
-	b.configLookup = newArray2DHashSet(nil, equalATNConfigs)
+	b.configLookup = NewJStore[ATNConfig, Comparator[ATNConfig]](&BaseATNConfigComparator[ATNConfig]{})
 }
 
 func (b *BaseATNConfigSet) FullContext() bool {
@@ -392,7 +396,8 @@ type OrderedATNConfigSet struct {
 func NewOrderedATNConfigSet() *OrderedATNConfigSet {
 	b := NewBaseATNConfigSet(false)
 
-	b.configLookup = newArray2DHashSet(nil, nil)
+	// This set uses the standard Hash() and Equals() from ATNConfig
+	b.configLookup = NewJStore[ATNConfig, Comparator[ATNConfig]](&ObjEqComparator[ATNConfig]{})
 
 	return &OrderedATNConfigSet{BaseATNConfigSet: b}
 }
@@ -402,7 +407,7 @@ func hashATNConfig(i interface{}) int {
 	hash := 7
 	hash = 31*hash + o.GetState().GetStateNumber()
 	hash = 31*hash + o.GetAlt()
-	hash = 31*hash + o.GetSemanticContext().hash()
+	hash = 31*hash + o.GetSemanticContext().Hash()
 	return hash
 }
 
@@ -430,5 +435,5 @@ func equalATNConfigs(a, b interface{}) bool {
 		return false
 	}
 
-	return ai.GetSemanticContext().equals(bi.GetSemanticContext())
+	return ai.GetSemanticContext().Equals(bi.GetSemanticContext())
 }

runtime/Go/antlr/atn_state.go

@@ -49,7 +49,8 @@ type ATNState interface {
 	AddTransition(Transition, int)
 
 	String() string
-	hash() int
+	Hash() int
+	Equals(Collectable[ATNState]) bool
 }
 
 type BaseATNState struct {
@@ -123,15 +124,15 @@ func (as *BaseATNState) SetNextTokenWithinRule(v *IntervalSet) {
 	as.NextTokenWithinRule = v
 }
 
-func (as *BaseATNState) hash() int {
+func (as *BaseATNState) Hash() int {
 	return as.stateNumber
 }
 
 func (as *BaseATNState) String() string {
 	return strconv.Itoa(as.stateNumber)
 }
 
-func (as *BaseATNState) equals(other interface{}) bool {
+func (as *BaseATNState) Equals(other Collectable[ATNState]) bool {
 	if ot, ok := other.(ATNState); ok {
 		return as.stateNumber == ot.GetStateNumber()
 	}