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// Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
// Use of this file is governed by the BSD 3-clause license that
// can be found in the LICENSE.txt file in the project root.
package antlr
// The root of the ANTLR exception hierarchy. In general, ANTLR tracks just
// 3 kinds of errors: prediction errors, failed predicate errors, and
// mismatched input errors. In each case, the parser knows where it is
// in the input, where it is in the ATN, the rule invocation stack,
// and what kind of problem occurred.
type RecognitionException interface {
GetOffendingToken() Token
GetMessage() string
GetInputStream() IntStream
}
type BaseRecognitionException struct {
message string
recognizer Recognizer
offendingToken Token
offendingState int
ctx RuleContext
input IntStream
}
func NewBaseRecognitionException(message string, recognizer Recognizer, input IntStream, ctx RuleContext) *BaseRecognitionException {
// todo
// Error.call(this)
//
// if (!!Error.captureStackTrace) {
// Error.captureStackTrace(this, RecognitionException)
// } else {
// stack := NewError().stack
// }
// TODO may be able to use - "runtime" func Stack(buf []byte, all bool) int
t := new(BaseRecognitionException)
t.message = message
t.recognizer = recognizer
t.input = input
t.ctx = ctx
// The current {@link Token} when an error occurred. Since not all streams
// support accessing symbols by index, we have to track the {@link Token}
// instance itself.
t.offendingToken = nil
// Get the ATN state number the parser was in at the time the error
// occurred. For {@link NoViableAltException} and
// {@link LexerNoViableAltException} exceptions, this is the
// {@link DecisionState} number. For others, it is the state whose outgoing
// edge we couldn't Match.
t.offendingState = -1
if t.recognizer != nil {
t.offendingState = t.recognizer.GetState()
}
return t
}
func (b *BaseRecognitionException) GetMessage() string {
return b.message
}
func (b *BaseRecognitionException) GetOffendingToken() Token {
return b.offendingToken
}
func (b *BaseRecognitionException) GetInputStream() IntStream {
return b.input
}
// <p>If the state number is not known, b method returns -1.</p>
//
// Gets the set of input symbols which could potentially follow the
// previously Matched symbol at the time b exception was panicn.
//
// <p>If the set of expected tokens is not known and could not be computed,
// b method returns {@code nil}.</p>
//
// @return The set of token types that could potentially follow the current
// state in the ATN, or {@code nil} if the information is not available.
// /
func (b *BaseRecognitionException) getExpectedTokens() *IntervalSet {
if b.recognizer != nil {
return b.recognizer.GetATN().getExpectedTokens(b.offendingState, b.ctx)
}
return nil
}
func (b *BaseRecognitionException) String() string {
return b.message
}
type LexerNoViableAltException struct {
*BaseRecognitionException
startIndex int
deadEndConfigs ATNConfigSet
}
func NewLexerNoViableAltException(lexer Lexer, input CharStream, startIndex int, deadEndConfigs ATNConfigSet) *LexerNoViableAltException {
l := new(LexerNoViableAltException)
l.BaseRecognitionException = NewBaseRecognitionException("", lexer, input, nil)
l.startIndex = startIndex
l.deadEndConfigs = deadEndConfigs
return l
}
func (l *LexerNoViableAltException) String() string {
symbol := ""
if l.startIndex >= 0 && l.startIndex < l.input.Size() {
symbol = l.input.(CharStream).GetTextFromInterval(NewInterval(l.startIndex, l.startIndex))
}
return "LexerNoViableAltException" + symbol
}
type NoViableAltException struct {
*BaseRecognitionException
startToken Token
offendingToken Token
ctx ParserRuleContext
deadEndConfigs ATNConfigSet
}
// Indicates that the parser could not decide which of two or more paths
// to take based upon the remaining input. It tracks the starting token
// of the offending input and also knows where the parser was
// in the various paths when the error. Reported by ReportNoViableAlternative()
//
func NewNoViableAltException(recognizer Parser, input TokenStream, startToken Token, offendingToken Token, deadEndConfigs ATNConfigSet, ctx ParserRuleContext) *NoViableAltException {
if ctx == nil {
ctx = recognizer.GetParserRuleContext()
}
if offendingToken == nil {
offendingToken = recognizer.GetCurrentToken()
}
if startToken == nil {
startToken = recognizer.GetCurrentToken()
}
if input == nil {
input = recognizer.GetInputStream().(TokenStream)
}
n := new(NoViableAltException)
n.BaseRecognitionException = NewBaseRecognitionException("", recognizer, input, ctx)
// Which configurations did we try at input.Index() that couldn't Match
// input.LT(1)?//
n.deadEndConfigs = deadEndConfigs
// The token object at the start index the input stream might
// not be buffering tokens so get a reference to it. (At the
// time the error occurred, of course the stream needs to keep a
// buffer all of the tokens but later we might not have access to those.)
n.startToken = startToken
n.offendingToken = offendingToken
return n
}
type InputMisMatchException struct {
*BaseRecognitionException
}
// This signifies any kind of mismatched input exceptions such as
// when the current input does not Match the expected token.
//
func NewInputMisMatchException(recognizer Parser) *InputMisMatchException {
i := new(InputMisMatchException)
i.BaseRecognitionException = NewBaseRecognitionException("", recognizer, recognizer.GetInputStream(), recognizer.GetParserRuleContext())
i.offendingToken = recognizer.GetCurrentToken()
return i
}
// A semantic predicate failed during validation. Validation of predicates
// occurs when normally parsing the alternative just like Matching a token.
// Disambiguating predicate evaluation occurs when we test a predicate during
// prediction.
type FailedPredicateException struct {
*BaseRecognitionException
ruleIndex int
predicateIndex int
predicate string
}
func NewFailedPredicateException(recognizer Parser, predicate string, message string) *FailedPredicateException {
f := new(FailedPredicateException)
f.BaseRecognitionException = NewBaseRecognitionException(f.formatMessage(predicate, message), recognizer, recognizer.GetInputStream(), recognizer.GetParserRuleContext())
s := recognizer.GetInterpreter().atn.states[recognizer.GetState()]
trans := s.GetTransitions()[0]
if trans2, ok := trans.(*PredicateTransition); ok {
f.ruleIndex = trans2.ruleIndex
f.predicateIndex = trans2.predIndex
} else {
f.ruleIndex = 0
f.predicateIndex = 0
}
f.predicate = predicate
f.offendingToken = recognizer.GetCurrentToken()
return f
}
func (f *FailedPredicateException) formatMessage(predicate, message string) string {
if message != "" {
return message
}
return "failed predicate: {" + predicate + "}?"
}
type ParseCancellationException struct {
}
func NewParseCancellationException() *ParseCancellationException {
// Error.call(this)
// Error.captureStackTrace(this, ParseCancellationException)
return new(ParseCancellationException)
}
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