init

vendor/github.com/awalterschulze/gographviz/internal/parser/parser.go

@@ -0,0 +1,216 @@
+// Code generated by gocc; DO NOT EDIT.
+
+package parser
+
+import (
+	"bytes"
+	"fmt"
+
+	parseError "github.com/awalterschulze/gographviz/internal/errors"
+	"github.com/awalterschulze/gographviz/internal/token"
+)
+
+const (
+	numProductions = 60
+	numStates      = 128
+	numSymbols     = 36
+)
+
+// Stack
+
+type stack struct {
+	state  []int
+	attrib []Attrib
+}
+
+const iNITIAL_STACK_SIZE = 100
+
+func newStack() *stack {
+	return &stack{
+		state:  make([]int, 0, iNITIAL_STACK_SIZE),
+		attrib: make([]Attrib, 0, iNITIAL_STACK_SIZE),
+	}
+}
+
+func (s *stack) reset() {
+	s.state = s.state[:0]
+	s.attrib = s.attrib[:0]
+}
+
+func (s *stack) push(state int, a Attrib) {
+	s.state = append(s.state, state)
+	s.attrib = append(s.attrib, a)
+}
+
+func (s *stack) top() int {
+	return s.state[len(s.state)-1]
+}
+
+func (s *stack) peek(pos int) int {
+	return s.state[pos]
+}
+
+func (s *stack) topIndex() int {
+	return len(s.state) - 1
+}
+
+func (s *stack) popN(items int) []Attrib {
+	lo, hi := len(s.state)-items, len(s.state)
+
+	attrib := s.attrib[lo:hi]
+
+	s.state = s.state[:lo]
+	s.attrib = s.attrib[:lo]
+
+	return attrib
+}
+
+func (s *stack) String() string {
+	w := new(bytes.Buffer)
+	fmt.Fprintf(w, "stack:\n")
+	for i, st := range s.state {
+		fmt.Fprintf(w, "\t%d: %d , ", i, st)
+		if s.attrib[i] == nil {
+			fmt.Fprintf(w, "nil")
+		} else {
+			switch attr := s.attrib[i].(type) {
+			case *token.Token:
+				fmt.Fprintf(w, "%s", attr.Lit)
+			default:
+				fmt.Fprintf(w, "%v", attr)
+			}
+		}
+		fmt.Fprintf(w, "\n")
+	}
+	return w.String()
+}
+
+// Parser
+
+type Parser struct {
+	stack     *stack
+	nextToken *token.Token
+	pos       int
+}
+
+type Scanner interface {
+	Scan() (tok *token.Token)
+}
+
+func NewParser() *Parser {
+	p := &Parser{stack: newStack()}
+	p.Reset()
+	return p
+}
+
+func (p *Parser) Reset() {
+	p.stack.reset()
+	p.stack.push(0, nil)
+}
+
+func (p *Parser) Error(err error, scanner Scanner) (recovered bool, errorAttrib *parseError.Error) {
+	errorAttrib = &parseError.Error{
+		Err:            err,
+		ErrorToken:     p.nextToken,
+		ErrorSymbols:   p.popNonRecoveryStates(),
+		ExpectedTokens: make([]string, 0, 8),
+	}
+	for t, action := range actionTab[p.stack.top()].actions {
+		if action != nil {
+			errorAttrib.ExpectedTokens = append(errorAttrib.ExpectedTokens, token.TokMap.Id(token.Type(t)))
+		}
+	}
+
+	if action := actionTab[p.stack.top()].actions[token.TokMap.Type("error")]; action != nil {
+		p.stack.push(int(action.(shift)), errorAttrib) // action can only be shift
+	} else {
+		return
+	}
+
+	if action := actionTab[p.stack.top()].actions[p.nextToken.Type]; action != nil {
+		recovered = true
+	}
+	for !recovered && p.nextToken.Type != token.EOF {
+		p.nextToken = scanner.Scan()
+		if action := actionTab[p.stack.top()].actions[p.nextToken.Type]; action != nil {
+			recovered = true
+		}
+	}
+
+	return
+}
+
+func (p *Parser) popNonRecoveryStates() (removedAttribs []parseError.ErrorSymbol) {
+	if rs, ok := p.firstRecoveryState(); ok {
+		errorSymbols := p.stack.popN(p.stack.topIndex() - rs)
+		removedAttribs = make([]parseError.ErrorSymbol, len(errorSymbols))
+		for i, e := range errorSymbols {
+			removedAttribs[i] = e
+		}
+	} else {
+		removedAttribs = []parseError.ErrorSymbol{}
+	}
+	return
+}
+
+// recoveryState points to the highest state on the stack, which can recover
+func (p *Parser) firstRecoveryState() (recoveryState int, canRecover bool) {
+	recoveryState, canRecover = p.stack.topIndex(), actionTab[p.stack.top()].canRecover
+	for recoveryState > 0 && !canRecover {
+		recoveryState--
+		canRecover = actionTab[p.stack.peek(recoveryState)].canRecover
+	}
+	return
+}
+
+func (p *Parser) newError(err error) error {
+	e := &parseError.Error{
+		Err:        err,
+		StackTop:   p.stack.top(),
+		ErrorToken: p.nextToken,
+	}
+	actRow := actionTab[p.stack.top()]
+	for i, t := range actRow.actions {
+		if t != nil {
+			e.ExpectedTokens = append(e.ExpectedTokens, token.TokMap.Id(token.Type(i)))
+		}
+	}
+	return e
+}
+
+func (p *Parser) Parse(scanner Scanner) (res interface{}, err error) {
+	p.Reset()
+	p.nextToken = scanner.Scan()
+	for acc := false; !acc; {
+		action := actionTab[p.stack.top()].actions[p.nextToken.Type]
+		if action == nil {
+			if recovered, errAttrib := p.Error(nil, scanner); !recovered {
+				p.nextToken = errAttrib.ErrorToken
+				return nil, p.newError(nil)
+			}
+			if action = actionTab[p.stack.top()].actions[p.nextToken.Type]; action == nil {
+				panic("Error recovery led to invalid action")
+			}
+		}
+
+		switch act := action.(type) {
+		case accept:
+			res = p.stack.popN(1)[0]
+			acc = true
+		case shift:
+			p.stack.push(int(act), p.nextToken)
+			p.nextToken = scanner.Scan()
+		case reduce:
+			prod := productionsTable[int(act)]
+			attrib, err := prod.ReduceFunc(p.stack.popN(prod.NumSymbols))
+			if err != nil {
+				return nil, p.newError(err)
+			} else {
+				p.stack.push(gotoTab[p.stack.top()][prod.NTType], attrib)
+			}
+		default:
+			panic("unknown action: " + action.String())
+		}
+	}
+	return res, nil
+}