fix: Allow CommonTokenStream to reset properly

  - There is a flag in CommonTokenStream that indicates whether EOF has
    already been fetched/seen. This was not being reset when a new TokenSource
    was given to an existing CommonTokenStream and there was no Reset() function
    which was unfortunately not exported and not part of the interface for TokenStream.
  - Reset the flag when a new source is provided
  - Export the Reset() function so that a TokenStream can be rewound

Signed-off-by: Jim.Idle <jimi@idle.ws>

runtime/Go/antlr/v4/common_token_stream.go

@@ -66,7 +66,9 @@ func (c *CommonTokenStream) Mark() int {
 
 func (c *CommonTokenStream) Release(_ int) {}
 
-func (c *CommonTokenStream) reset() {
+func (c *CommonTokenStream) Reset() {
+	c.fetchedEOF = false
+	c.tokens = make([]Token, 0)
 	c.Seek(0)
 }
 
@@ -196,6 +198,7 @@ func (c *CommonTokenStream) SetTokenSource(tokenSource TokenSource) {
 	c.tokenSource = tokenSource
 	c.tokens = make([]Token, 0)
 	c.index = -1
+	c.fetchedEOF = false
 }
 
 // NextTokenOnChannel returns the index of the next token on channel given a

runtime/Go/antlr/v4/token_stream.go

@@ -8,6 +8,7 @@ type TokenStream interface {
 	IntStream
 
 	LT(k int) Token
+	Reset()
 
 	Get(index int) Token
 	GetTokenSource() TokenSource

runtime/Go/antlr/v4/tokenstream_rewriter.go

@@ -304,7 +304,7 @@ func (tsr *TokenStreamRewriter) RollbackDefault(instructionIndex int) {
 	tsr.Rollback(DefaultProgramName, instructionIndex)
 }
 
-// DeleteProgram reset the program so that no instructions exist
+// DeleteProgram Reset the program so that no instructions exist
 func (tsr *TokenStreamRewriter) DeleteProgram(programName string) {
 	tsr.Rollback(programName, MinTokenIndex) //TODO: double test on that cause lower bound is not included
 }