示例#1
0
文件: dfa.go 项目: cznic/lex
func (n *nfa) powerSet() (d *dfa) {
	d = &dfa{}
	m := map[string]*lexer.NfaState{}

	s := func(c map[int]*stateSet, i int) (p *stateSet) {
		if !bits32 && !(i >= 0 && i <= 255) {
			panic(fmt.Errorf("unsupported value %d > 255", i))
		}

		p, ok := c[i]
		if !ok {
			p = newStateSet(len(n.nfa))
			c[i] = p
		}
		return
	}

	var f func(*stateSet) *lexer.NfaState

	f = func(closure *stateSet) (state *lexer.NfaState) {
		var prio int
		id := closure.id()
		state, ok := m[id]
		if !ok {
			state = d.nfa.nfa.NewState()
			m[id] = state
			if closure.has(n.out, &prio) {
				d.accept = append(d.accept, state)
				d.acceptRule = append(d.acceptRule, prio)
			}
			closures := map[int]*stateSet{}
			for i := uint(0); i < closure.count; i++ {
				nfaState := n.nfa[closure.dense[i].id]
				prio = closure.dense[i].priority
				for _, edge := range nfaState.Consuming {
					p := edge.Priority()
					if p == 0 {
						p = prio
					}
					switch x := edge.(type) {
					default:
						panic(fmt.Errorf("unexpeceted type %T", edge))
					case *lexer.RuneEdge:
						s(closures, int(x.Rune)).closure(x.Target(), p)
					case *lexer.RangesEdge:
						if !bits32 {
							var m [256]bool
							for _, r := range x.Ranges.R16 {
								for c := r.Lo; c <= r.Hi; c += r.Stride {
									m[c] = true
								}
							}
							for _, r := range x.Ranges.R32 {
								for c := r.Lo; c <= r.Hi; c += r.Stride {
									m[c] = true
								}
							}
							for i, v := range m {
								if v != x.Invert {
									s(closures, i).closure(x.Target(), p)
								}
							}
						} else { // bits32
							panic("unreachable")
							/* mode32 disabled
							r := rangeSlice(x.Ranges)
							if x.Invert {
								r.invert()
							}
							cnt := 0
							for _, v := range r {
								for c := v.Lo; c <= v.Hi; c += v.Stride {
									cnt++
									if cnt > 256 {
										panic(fmt.Errorf("not yet implemented feature"))
									}
									s(closures, c).closure(x.Target(), p)
								}
							}
							*/
						}
					}
				}
			}
			mm := map[*lexer.NfaState][]int{}

			// Stabilize
			a := []int{}
			for char := range closures {
				a = append(a, char)
			}
			sort.Ints(a)
			for _, char := range a {
				closure = closures[char]
				state := f(closure)
				mm[state] = append(mm[state], char)
			}

			// Stabilize
			ai, as := []int{}, map[int]*lexer.NfaState{}
			for s := range mm {
				i := int(s.Index)
				ai = append(ai, i)
				as[i] = s
			}
			sort.Ints(ai)
			for _, si := range ai {
				s := as[si]
				slice := mm[s]
				switch len(slice) {
				case 1:
					state.AddConsuming(lexer.NewRuneEdge(s, rune(slice[0])))
				default:
					r := []unicode.Range32{}
					for _, char := range slice {
						r = append(r, unicode.Range32{uint32(char), uint32(char), 1})
					}
					(*rangeSlice)(&r).normalize()
					state.AddConsuming(lexer.NewRangesEdge(s, false, &unicode.RangeTable{R32: r}))
				}
			}
		}
		return
	}

	d.nfa.in = f(newStateSet(len(n.nfa)).closure(n.in, 0))
	return
}
示例#2
0
文件: dfa.go 项目: cznic/lex
func computeAllNfa() {
	in, out := allNfa.nfa.NewState(), allNfa.nfa.NewState()
	seenBol := false
	for irule, dfa := range partialDFAs {
		if irule == 0 {
			continue
		}

		if rules[irule].bol {
			seenBol = true
			continue
		}

		ruleIn := allNfa.nfa.NewState()
		rules[irule].in = ruleIn
		// an irule priority e-edge from ruleIn to the partial dfa.in
		ruleIn.AddNonConsuming(&lexer.EpsilonEdge{irule, dfa.in})
		for _, state := range dfa.nfa.nfa {
			allNfa.nfa.AddState(state)
		}
		for _, state := range dfa.accept {
			state.AddNonConsuming(&lexer.EpsilonEdge{0, out})
		}
		conds := rules[irule].conds
		if len(conds) == 0 { // rule is active in all non exclusive start conditions
			for _, sc := range sStarts {
				in.AddConsuming(lexer.NewRuneEdge(ruleIn, rune(iStarts[sc])))
			}
			continue
		}

		// len(conds) != 0
		for _, sc := range conds {
			if sc != "*" { // rule is active in all its explicitly declared start conditions
				in.AddConsuming(lexer.NewRuneEdge(ruleIn, rune(iStarts[sc])))
				continue
			}

			// sc == "*", rule is always active
			for sc := range defStarts {
				in.AddConsuming(lexer.NewRuneEdge(ruleIn, rune(iStarts[sc])))
			}
		}
	}

	if seenBol {
		for irule, dfa := range partialDFAs {
			if irule == 0 {
				continue
			}

			ruleIn := allNfa.nfa.NewState()
			rules[irule].bolIn = ruleIn
			// an irule priority e-edge from ruleIn to the partial dfa.in
			ruleIn.AddNonConsuming(&lexer.EpsilonEdge{irule, dfa.in})
			for _, state := range dfa.nfa.nfa {
				allNfa.nfa.AddState(state)
			}
			for _, state := range dfa.accept {
				state.AddNonConsuming(&lexer.EpsilonEdge{0, out})
			}
			conds := rules[irule].conds
			if len(conds) == 0 { // rule is active in all non exclusive start conditions
				for _, sc := range sStarts {
					in.AddConsuming(lexer.NewRuneEdge(ruleIn, rune(iStarts[sc]+128)))
				}
				continue
			}

			// len(conds) != 0
			for _, sc := range conds {
				if sc != "*" { // rule is active in all its explicitly declared start conditions
					in.AddConsuming(lexer.NewRuneEdge(ruleIn, rune(iStarts[sc]+128)))
					continue
				}

				// sc == "*", rule is always active
				for sc := range defStarts {
					in.AddConsuming(lexer.NewRuneEdge(ruleIn, rune(iStarts[sc]+128)))
				}
			}
		}
	}
	allNfa.in, allNfa.out = in, out
}