func TestNNF(t *testing.T) {
// Build a simple BNF aGrammar description aGrammar.
gb := parser.OpenGrammarBuilder()
gb.Name("a4").
Terminals("a").
Nonterminals("S", "A", "E").
Rule().Lhs("`*").Rhs("S", "`.").
Rule().Lhs("S").Rhs("A", "A", "A", "A").
Rule().Lhs("A").Rhs("a").
Rule().Lhs("A").Rhs("E").
Rule().Lhs("E").Rhs("`e")
g, err := gb.Build()
if err != nil {
t.Error(err)
return
}
var aGrammar parser.Grammar
var rTransform parser.SyntaxTreeTransform
nnf, err := IsNihilisticNormalForm(g)
if err != nil {
t.Error()
return
}
if !nnf {
fmt.Println("Grammar is not NNF, transforming.")
aGrammar, rTransform, err = GetNihilisticAugmentGrammar(g)
if err != nil {
t.Error(err)
return
}
} else {
t.Error("Grammar returned NNF.")
return
}
fmt.Println("Name: " + aGrammar.Name())
terms := make([]string, aGrammar.NumTerminals())
for i, t := range aGrammar.Terminals() {
terms[i] = t.String()
}
nterms := make([]string, aGrammar.NumNonterminals())
for i, t := range aGrammar.Nonterminals() {
nterms[i] = t.String()
}
fmt.Println("Terminals: " + strings.Join(terms, ", "))
fmt.Println("Nonterminals: " + strings.Join(nterms, ", "))
fmt.Println("Productions:")
for _, p := range aGrammar.Productions() {
fmt.Println(" " + p.String())
}
rTransform = rTransform
}
func (ni *NameIndex) Initialize(g parser.Grammar) error {
ni.nonterminalsByName = make(map[string]parser.GrammarParticle)
ni.terminalsByName = make(map[string]parser.GrammarParticle)
for i := 0; i < g.NumNonterminals(); i++ {
nt := g.Nonterminal(i)
ni.nonterminalsByName[nt.Name()] = nt
}
for i := 0; i < g.NumTerminals(); i++ {
t := g.Terminal(i)
ni.terminalsByName[t.Name()] = t
}
ni.lhsNames = make(map[string][]parser.Production)
ni.rhsNames = make(map[string][]parser.Production)
for _, p := range g.Productions() {
var rhs, lhs []byte
for i := 0; i < p.LhsLen(); i++ {
lhs = append(lhs, p.Lhs(i).Name()...)
if i < p.LhsLen()-1 {
lhs = append(lhs, "|"...)
}
}
if _, has := ni.lhsNames[string(lhs)]; !has {
ni.lhsNames[string(lhs)] = []parser.Production{}
}
ni.lhsNames[string(lhs)] = append(ni.lhsNames[string(lhs)], p)
for i := 0; i < p.RhsLen(); i++ {
rhs = append(rhs, p.Rhs(i).Name()...)
if i < p.RhsLen()-1 {
rhs = append(rhs, "|"...)
}
}
if _, has := ni.rhsNames[string(rhs)]; !has {
ni.rhsNames[string(rhs)] = []parser.Production{}
}
ni.rhsNames[string(rhs)] = append(ni.rhsNames[string(rhs)], p)
}
return nil
}