Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
3 contributors

Users who have contributed to this file

@willfaught @parrt @pboyer
719 lines (627 sloc) 19.4 KB
// 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
import (
"fmt"
"strconv"
)
type Parser interface {
Recognizer
GetInterpreter() *ParserATNSimulator
GetTokenStream() TokenStream
GetTokenFactory() TokenFactory
GetParserRuleContext() ParserRuleContext
SetParserRuleContext(ParserRuleContext)
Consume() Token
GetParseListeners() []ParseTreeListener
GetErrorHandler() ErrorStrategy
SetErrorHandler(ErrorStrategy)
GetInputStream() IntStream
GetCurrentToken() Token
GetExpectedTokens() *IntervalSet
NotifyErrorListeners(string, Token, RecognitionException)
IsExpectedToken(int) bool
GetPrecedence() int
GetRuleInvocationStack(ParserRuleContext) []string
}
type BaseParser struct {
*BaseRecognizer
Interpreter *ParserATNSimulator
BuildParseTrees bool
input TokenStream
errHandler ErrorStrategy
precedenceStack IntStack
ctx ParserRuleContext
tracer *TraceListener
parseListeners []ParseTreeListener
_SyntaxErrors int
}
// p.is all the parsing support code essentially most of it is error
// recovery stuff.//
func NewBaseParser(input TokenStream) *BaseParser {
p := new(BaseParser)
p.BaseRecognizer = NewBaseRecognizer()
// The input stream.
p.input = nil
// The error handling strategy for the parser. The default value is a new
// instance of {@link DefaultErrorStrategy}.
p.errHandler = NewDefaultErrorStrategy()
p.precedenceStack = make([]int, 0)
p.precedenceStack.Push(0)
// The {@link ParserRuleContext} object for the currently executing rule.
// p.is always non-nil during the parsing process.
p.ctx = nil
// Specifies whether or not the parser should construct a parse tree during
// the parsing process. The default value is {@code true}.
p.BuildParseTrees = true
// When {@link //setTrace}{@code (true)} is called, a reference to the
// {@link TraceListener} is stored here so it can be easily removed in a
// later call to {@link //setTrace}{@code (false)}. The listener itself is
// implemented as a parser listener so p.field is not directly used by
// other parser methods.
p.tracer = nil
// The list of {@link ParseTreeListener} listeners registered to receive
// events during the parse.
p.parseListeners = nil
// The number of syntax errors Reported during parsing. p.value is
// incremented each time {@link //NotifyErrorListeners} is called.
p._SyntaxErrors = 0
p.SetInputStream(input)
return p
}
// p.field maps from the serialized ATN string to the deserialized {@link
// ATN} with
// bypass alternatives.
//
// @see ATNDeserializationOptions//isGenerateRuleBypassTransitions()
//
var bypassAltsAtnCache = make(map[string]int)
// reset the parser's state//
func (p *BaseParser) reset() {
if p.input != nil {
p.input.Seek(0)
}
p.errHandler.reset(p)
p.ctx = nil
p._SyntaxErrors = 0
p.SetTrace(nil)
p.precedenceStack = make([]int, 0)
p.precedenceStack.Push(0)
if p.Interpreter != nil {
p.Interpreter.reset()
}
}
func (p *BaseParser) GetErrorHandler() ErrorStrategy {
return p.errHandler
}
func (p *BaseParser) SetErrorHandler(e ErrorStrategy) {
p.errHandler = e
}
// Match current input symbol against {@code ttype}. If the symbol type
// Matches, {@link ANTLRErrorStrategy//ReportMatch} and {@link //consume} are
// called to complete the Match process.
//
// <p>If the symbol type does not Match,
// {@link ANTLRErrorStrategy//recoverInline} is called on the current error
// strategy to attempt recovery. If {@link //getBuildParseTree} is
// {@code true} and the token index of the symbol returned by
// {@link ANTLRErrorStrategy//recoverInline} is -1, the symbol is added to
// the parse tree by calling {@link ParserRuleContext//addErrorNode}.</p>
//
// @param ttype the token type to Match
// @return the Matched symbol
// @panics RecognitionException if the current input symbol did not Match
// {@code ttype} and the error strategy could not recover from the
// mismatched symbol
func (p *BaseParser) Match(ttype int) Token {
t := p.GetCurrentToken()
if t.GetTokenType() == ttype {
p.errHandler.ReportMatch(p)
p.Consume()
} else {
t = p.errHandler.RecoverInline(p)
if p.BuildParseTrees && t.GetTokenIndex() == -1 {
// we must have conjured up a Newtoken during single token
// insertion
// if it's not the current symbol
p.ctx.AddErrorNode(t)
}
}
return t
}
// Match current input symbol as a wildcard. If the symbol type Matches
// (i.e. has a value greater than 0), {@link ANTLRErrorStrategy//ReportMatch}
// and {@link //consume} are called to complete the Match process.
//
// <p>If the symbol type does not Match,
// {@link ANTLRErrorStrategy//recoverInline} is called on the current error
// strategy to attempt recovery. If {@link //getBuildParseTree} is
// {@code true} and the token index of the symbol returned by
// {@link ANTLRErrorStrategy//recoverInline} is -1, the symbol is added to
// the parse tree by calling {@link ParserRuleContext//addErrorNode}.</p>
//
// @return the Matched symbol
// @panics RecognitionException if the current input symbol did not Match
// a wildcard and the error strategy could not recover from the mismatched
// symbol
func (p *BaseParser) MatchWildcard() Token {
t := p.GetCurrentToken()
if t.GetTokenType() > 0 {
p.errHandler.ReportMatch(p)
p.Consume()
} else {
t = p.errHandler.RecoverInline(p)
if p.BuildParseTrees && t.GetTokenIndex() == -1 {
// we must have conjured up a Newtoken during single token
// insertion
// if it's not the current symbol
p.ctx.AddErrorNode(t)
}
}
return t
}
func (p *BaseParser) GetParserRuleContext() ParserRuleContext {
return p.ctx
}
func (p *BaseParser) SetParserRuleContext(v ParserRuleContext) {
p.ctx = v
}
func (p *BaseParser) GetParseListeners() []ParseTreeListener {
if p.parseListeners == nil {
return make([]ParseTreeListener, 0)
}
return p.parseListeners
}
// Registers {@code listener} to receive events during the parsing process.
//
// <p>To support output-preserving grammar transformations (including but not
// limited to left-recursion removal, automated left-factoring, and
// optimized code generation), calls to listener methods during the parse
// may differ substantially from calls made by
// {@link ParseTreeWalker//DEFAULT} used after the parse is complete. In
// particular, rule entry and exit events may occur in a different order
// during the parse than after the parser. In addition, calls to certain
// rule entry methods may be omitted.</p>
//
// <p>With the following specific exceptions, calls to listener events are
// <em>deterministic</em>, i.e. for identical input the calls to listener
// methods will be the same.</p>
//
// <ul>
// <li>Alterations to the grammar used to generate code may change the
// behavior of the listener calls.</li>
// <li>Alterations to the command line options passed to ANTLR 4 when
// generating the parser may change the behavior of the listener calls.</li>
// <li>Changing the version of the ANTLR Tool used to generate the parser
// may change the behavior of the listener calls.</li>
// </ul>
//
// @param listener the listener to add
//
// @panics nilPointerException if {@code} listener is {@code nil}
//
func (p *BaseParser) AddParseListener(listener ParseTreeListener) {
if listener == nil {
panic("listener")
}
if p.parseListeners == nil {
p.parseListeners = make([]ParseTreeListener, 0)
}
p.parseListeners = append(p.parseListeners, listener)
}
//
// Remove {@code listener} from the list of parse listeners.
//
// <p>If {@code listener} is {@code nil} or has not been added as a parse
// listener, p.method does nothing.</p>
// @param listener the listener to remove
//
func (p *BaseParser) RemoveParseListener(listener ParseTreeListener) {
if p.parseListeners != nil {
idx := -1
for i, v := range p.parseListeners {
if v == listener {
idx = i
break
}
}
if idx == -1 {
return
}
// remove the listener from the slice
p.parseListeners = append(p.parseListeners[0:idx], p.parseListeners[idx+1:]...)
if len(p.parseListeners) == 0 {
p.parseListeners = nil
}
}
}
// Remove all parse listeners.
func (p *BaseParser) removeParseListeners() {
p.parseListeners = nil
}
// Notify any parse listeners of an enter rule event.
func (p *BaseParser) TriggerEnterRuleEvent() {
if p.parseListeners != nil {
ctx := p.ctx
for _, listener := range p.parseListeners {
listener.EnterEveryRule(ctx)
ctx.EnterRule(listener)
}
}
}
//
// Notify any parse listeners of an exit rule event.
//
// @see //addParseListener
//
func (p *BaseParser) TriggerExitRuleEvent() {
if p.parseListeners != nil {
// reverse order walk of listeners
ctx := p.ctx
l := len(p.parseListeners) - 1
for i := range p.parseListeners {
listener := p.parseListeners[l-i]
ctx.ExitRule(listener)
listener.ExitEveryRule(ctx)
}
}
}
func (p *BaseParser) GetInterpreter() *ParserATNSimulator {
return p.Interpreter
}
func (p *BaseParser) GetATN() *ATN {
return p.Interpreter.atn
}
func (p *BaseParser) GetTokenFactory() TokenFactory {
return p.input.GetTokenSource().GetTokenFactory()
}
// Tell our token source and error strategy about a Newway to create tokens.//
func (p *BaseParser) setTokenFactory(factory TokenFactory) {
p.input.GetTokenSource().setTokenFactory(factory)
}
// The ATN with bypass alternatives is expensive to create so we create it
// lazily.
//
// @panics UnsupportedOperationException if the current parser does not
// implement the {@link //getSerializedATN()} method.
//
func (p *BaseParser) GetATNWithBypassAlts() {
// TODO
panic("Not implemented!")
// serializedAtn := p.getSerializedATN()
// if (serializedAtn == nil) {
// panic("The current parser does not support an ATN with bypass alternatives.")
// }
// result := p.bypassAltsAtnCache[serializedAtn]
// if (result == nil) {
// deserializationOptions := NewATNDeserializationOptions(nil)
// deserializationOptions.generateRuleBypassTransitions = true
// result = NewATNDeserializer(deserializationOptions).deserialize(serializedAtn)
// p.bypassAltsAtnCache[serializedAtn] = result
// }
// return result
}
// The preferred method of getting a tree pattern. For example, here's a
// sample use:
//
// <pre>
// ParseTree t = parser.expr()
// ParseTreePattern p = parser.compileParseTreePattern("&ltID&gt+0",
// MyParser.RULE_expr)
// ParseTreeMatch m = p.Match(t)
// String id = m.Get("ID")
// </pre>
func (p *BaseParser) compileParseTreePattern(pattern, patternRuleIndex, lexer Lexer) {
panic("NewParseTreePatternMatcher not implemented!")
//
// if (lexer == nil) {
// if (p.GetTokenStream() != nil) {
// tokenSource := p.GetTokenStream().GetTokenSource()
// if _, ok := tokenSource.(ILexer); ok {
// lexer = tokenSource
// }
// }
// }
// if (lexer == nil) {
// panic("Parser can't discover a lexer to use")
// }
// m := NewParseTreePatternMatcher(lexer, p)
// return m.compile(pattern, patternRuleIndex)
}
func (p *BaseParser) GetInputStream() IntStream {
return p.GetTokenStream()
}
func (p *BaseParser) SetInputStream(input TokenStream) {
p.SetTokenStream(input)
}
func (p *BaseParser) GetTokenStream() TokenStream {
return p.input
}
// Set the token stream and reset the parser.//
func (p *BaseParser) SetTokenStream(input TokenStream) {
p.input = nil
p.reset()
p.input = input
}
// Match needs to return the current input symbol, which gets put
// into the label for the associated token ref e.g., x=ID.
//
func (p *BaseParser) GetCurrentToken() Token {
return p.input.LT(1)
}
func (p *BaseParser) NotifyErrorListeners(msg string, offendingToken Token, err RecognitionException) {
if offendingToken == nil {
offendingToken = p.GetCurrentToken()
}
p._SyntaxErrors++
line := offendingToken.GetLine()
column := offendingToken.GetColumn()
listener := p.GetErrorListenerDispatch()
listener.SyntaxError(p, offendingToken, line, column, msg, err)
}
func (p *BaseParser) Consume() Token {
o := p.GetCurrentToken()
if o.GetTokenType() != TokenEOF {
p.GetInputStream().Consume()
}
hasListener := p.parseListeners != nil && len(p.parseListeners) > 0
if p.BuildParseTrees || hasListener {
if p.errHandler.inErrorRecoveryMode(p) {
node := p.ctx.AddErrorNode(o)
if p.parseListeners != nil {
for _, l := range p.parseListeners {
l.VisitErrorNode(node)
}
}
} else {
node := p.ctx.AddTokenNode(o)
if p.parseListeners != nil {
for _, l := range p.parseListeners {
l.VisitTerminal(node)
}
}
}
// node.invokingState = p.state
}
return o
}
func (p *BaseParser) addContextToParseTree() {
// add current context to parent if we have a parent
if p.ctx.GetParent() != nil {
p.ctx.GetParent().(ParserRuleContext).AddChild(p.ctx)
}
}
func (p *BaseParser) EnterRule(localctx ParserRuleContext, state, ruleIndex int) {
p.SetState(state)
p.ctx = localctx
p.ctx.SetStart(p.input.LT(1))
if p.BuildParseTrees {
p.addContextToParseTree()
}
if p.parseListeners != nil {
p.TriggerEnterRuleEvent()
}
}
func (p *BaseParser) ExitRule() {
p.ctx.SetStop(p.input.LT(-1))
// trigger event on ctx, before it reverts to parent
if p.parseListeners != nil {
p.TriggerExitRuleEvent()
}
p.SetState(p.ctx.GetInvokingState())
if p.ctx.GetParent() != nil {
p.ctx = p.ctx.GetParent().(ParserRuleContext)
} else {
p.ctx = nil
}
}
func (p *BaseParser) EnterOuterAlt(localctx ParserRuleContext, altNum int) {
localctx.SetAltNumber(altNum)
// if we have Newlocalctx, make sure we replace existing ctx
// that is previous child of parse tree
if p.BuildParseTrees && p.ctx != localctx {
if p.ctx.GetParent() != nil {
p.ctx.GetParent().(ParserRuleContext).RemoveLastChild()
p.ctx.GetParent().(ParserRuleContext).AddChild(localctx)
}
}
p.ctx = localctx
}
// Get the precedence level for the top-most precedence rule.
//
// @return The precedence level for the top-most precedence rule, or -1 if
// the parser context is not nested within a precedence rule.
func (p *BaseParser) GetPrecedence() int {
if len(p.precedenceStack) == 0 {
return -1
}
return p.precedenceStack[len(p.precedenceStack)-1]
}
func (p *BaseParser) EnterRecursionRule(localctx ParserRuleContext, state, ruleIndex, precedence int) {
p.SetState(state)
p.precedenceStack.Push(precedence)
p.ctx = localctx
p.ctx.SetStart(p.input.LT(1))
if p.parseListeners != nil {
p.TriggerEnterRuleEvent() // simulates rule entry for
// left-recursive rules
}
}
//
// Like {@link //EnterRule} but for recursive rules.
func (p *BaseParser) PushNewRecursionContext(localctx ParserRuleContext, state, ruleIndex int) {
previous := p.ctx
previous.SetParent(localctx)
previous.SetInvokingState(state)
previous.SetStop(p.input.LT(-1))
p.ctx = localctx
p.ctx.SetStart(previous.GetStart())
if p.BuildParseTrees {
p.ctx.AddChild(previous)
}
if p.parseListeners != nil {
p.TriggerEnterRuleEvent() // simulates rule entry for
// left-recursive rules
}
}
func (p *BaseParser) UnrollRecursionContexts(parentCtx ParserRuleContext) {
p.precedenceStack.Pop()
p.ctx.SetStop(p.input.LT(-1))
retCtx := p.ctx // save current ctx (return value)
// unroll so ctx is as it was before call to recursive method
if p.parseListeners != nil {
for p.ctx != parentCtx {
p.TriggerExitRuleEvent()
p.ctx = p.ctx.GetParent().(ParserRuleContext)
}
} else {
p.ctx = parentCtx
}
// hook into tree
retCtx.SetParent(parentCtx)
if p.BuildParseTrees && parentCtx != nil {
// add return ctx into invoking rule's tree
parentCtx.AddChild(retCtx)
}
}
func (p *BaseParser) GetInvokingContext(ruleIndex int) ParserRuleContext {
ctx := p.ctx
for ctx != nil {
if ctx.GetRuleIndex() == ruleIndex {
return ctx
}
ctx = ctx.GetParent().(ParserRuleContext)
}
return nil
}
func (p *BaseParser) Precpred(localctx RuleContext, precedence int) bool {
return precedence >= p.precedenceStack[len(p.precedenceStack)-1]
}
func (p *BaseParser) inContext(context ParserRuleContext) bool {
// TODO: useful in parser?
return false
}
//
// Checks whether or not {@code symbol} can follow the current state in the
// ATN. The behavior of p.method is equivalent to the following, but is
// implemented such that the complete context-sensitive follow set does not
// need to be explicitly constructed.
//
// <pre>
// return getExpectedTokens().contains(symbol)
// </pre>
//
// @param symbol the symbol type to check
// @return {@code true} if {@code symbol} can follow the current state in
// the ATN, otherwise {@code false}.
func (p *BaseParser) IsExpectedToken(symbol int) bool {
atn := p.Interpreter.atn
ctx := p.ctx
s := atn.states[p.state]
following := atn.NextTokens(s, nil)
if following.contains(symbol) {
return true
}
if !following.contains(TokenEpsilon) {
return false
}
for ctx != nil && ctx.GetInvokingState() >= 0 && following.contains(TokenEpsilon) {
invokingState := atn.states[ctx.GetInvokingState()]
rt := invokingState.GetTransitions()[0]
following = atn.NextTokens(rt.(*RuleTransition).followState, nil)
if following.contains(symbol) {
return true
}
ctx = ctx.GetParent().(ParserRuleContext)
}
if following.contains(TokenEpsilon) && symbol == TokenEOF {
return true
}
return false
}
// Computes the set of input symbols which could follow the current parser
// state and context, as given by {@link //GetState} and {@link //GetContext},
// respectively.
//
// @see ATN//getExpectedTokens(int, RuleContext)
//
func (p *BaseParser) GetExpectedTokens() *IntervalSet {
return p.Interpreter.atn.getExpectedTokens(p.state, p.ctx)
}
func (p *BaseParser) GetExpectedTokensWithinCurrentRule() *IntervalSet {
atn := p.Interpreter.atn
s := atn.states[p.state]
return atn.NextTokens(s, nil)
}
// Get a rule's index (i.e., {@code RULE_ruleName} field) or -1 if not found.//
func (p *BaseParser) GetRuleIndex(ruleName string) int {
var ruleIndex, ok = p.GetRuleIndexMap()[ruleName]
if ok {
return ruleIndex
}
return -1
}
// Return List&ltString&gt of the rule names in your parser instance
// leading up to a call to the current rule. You could override if
// you want more details such as the file/line info of where
// in the ATN a rule is invoked.
//
// this very useful for error messages.
func (p *BaseParser) GetRuleInvocationStack(c ParserRuleContext) []string {
if c == nil {
c = p.ctx
}
stack := make([]string, 0)
for c != nil {
// compute what follows who invoked us
ruleIndex := c.GetRuleIndex()
if ruleIndex < 0 {
stack = append(stack, "n/a")
} else {
stack = append(stack, p.GetRuleNames()[ruleIndex])
}
vp := c.GetParent()
if vp == nil {
break
}
c = vp.(ParserRuleContext)
}
return stack
}
// For debugging and other purposes.//
func (p *BaseParser) GetDFAStrings() string {
return fmt.Sprint(p.Interpreter.decisionToDFA)
}
// For debugging and other purposes.//
func (p *BaseParser) DumpDFA() {
seenOne := false
for _, dfa := range p.Interpreter.decisionToDFA {
if dfa.numStates() > 0 {
if seenOne {
fmt.Println()
}
fmt.Println("Decision " + strconv.Itoa(dfa.decision) + ":")
fmt.Print(dfa.String(p.LiteralNames, p.SymbolicNames))
seenOne = true
}
}
}
func (p *BaseParser) GetSourceName() string {
return p.GrammarFileName
}
// During a parse is sometimes useful to listen in on the rule entry and exit
// events as well as token Matches. p.is for quick and dirty debugging.
//
func (p *BaseParser) SetTrace(trace *TraceListener) {
if trace == nil {
p.RemoveParseListener(p.tracer)
p.tracer = nil
} else {
if p.tracer != nil {
p.RemoveParseListener(p.tracer)
}
p.tracer = NewTraceListener(p)
p.AddParseListener(p.tracer)
}
}
You can’t perform that action at this time.