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|
package grammar
import (
"fmt"
mlcompiler "github.com/nihei9/maleeni/compiler"
mlspec "github.com/nihei9/maleeni/spec"
"github.com/nihei9/vartan/spec"
)
type Grammar struct {
lexSpec *mlspec.LexSpec
productionSet *productionSet
augmentedStartSymbol symbol
symbolTable *symbolTable
}
func NewGrammar(root *spec.RootNode) (*Grammar, error) {
symTab := newSymbolTable()
anonPat2Sym := map[string]symbol{}
var lexSpec *mlspec.LexSpec
{
entries := []*mlspec.LexEntry{}
anonPats := []string{}
for _, prod := range root.Productions {
if isLexicalProduction(prod) {
_, err := symTab.registerTerminalSymbol(prod.LHS)
if err != nil {
return nil, err
}
entries = append(entries, &mlspec.LexEntry{
Kind: mlspec.LexKind(prod.LHS),
Pattern: mlspec.LexPattern(prod.RHS[0].Elements[0].Pattern),
})
continue
}
for _, alt := range prod.RHS {
for _, elem := range alt.Elements {
if elem.Pattern == "" {
continue
}
exist := false
for _, p := range anonPats {
if p == elem.Pattern {
exist = true
break
}
}
if exist {
continue
}
anonPats = append(anonPats, elem.Pattern)
}
}
}
for i, p := range anonPats {
kind := fmt.Sprintf("__%v__", i+1)
sym, err := symTab.registerTerminalSymbol(kind)
if err != nil {
return nil, err
}
anonPat2Sym[p] = sym
entries = append(entries, &mlspec.LexEntry{
Kind: mlspec.LexKind(kind),
Pattern: mlspec.LexPattern(p),
})
}
lexSpec = &mlspec.LexSpec{
Entries: entries,
}
}
prods := newProductionSet()
var augStartSym symbol
{
startProd := root.Productions[0]
augStartText := fmt.Sprintf("%s'", startProd.LHS)
var err error
augStartSym, err = symTab.registerStartSymbol(augStartText)
if err != nil {
return nil, err
}
startSym, err := symTab.registerNonTerminalSymbol(startProd.LHS)
if err != nil {
return nil, err
}
p, err := newProduction(augStartSym, []symbol{
startSym,
})
if err != nil {
return nil, err
}
prods.append(p)
for _, prod := range root.Productions {
if isLexicalProduction(prod) {
continue
}
_, err := symTab.registerNonTerminalSymbol(prod.LHS)
if err != nil {
return nil, err
}
}
for _, prod := range root.Productions {
if isLexicalProduction(prod) {
continue
}
lhsSym, ok := symTab.toSymbol(prod.LHS)
if !ok {
return nil, fmt.Errorf("symbol '%v' is undefined", prod.LHS)
}
for _, alt := range prod.RHS {
altSyms := make([]symbol, len(alt.Elements))
for i, elem := range alt.Elements {
var sym symbol
if elem.Pattern != "" {
var ok bool
sym, ok = anonPat2Sym[elem.Pattern]
if !ok {
return nil, fmt.Errorf("pattern '%v' is undefined", elem.Pattern)
}
} else {
var ok bool
sym, ok = symTab.toSymbol(elem.ID)
if !ok {
return nil, fmt.Errorf("symbol '%v' is undefined", elem.ID)
}
}
altSyms[i] = sym
}
p, err := newProduction(lhsSym, altSyms)
if err != nil {
return nil, err
}
prods.append(p)
}
}
}
return &Grammar{
lexSpec: lexSpec,
productionSet: prods,
augmentedStartSymbol: augStartSym,
symbolTable: symTab,
}, nil
}
func isLexicalProduction(prod *spec.ProductionNode) bool {
if len(prod.RHS) == 1 && len(prod.RHS[0].Elements) == 1 && prod.RHS[0].Elements[0].Pattern != "" {
return true
}
return false
}
func Compile(gram *Grammar) (*spec.CompiledGrammar, error) {
lexSpec, err := mlcompiler.Compile(gram.lexSpec, mlcompiler.CompressionLevel(mlcompiler.CompressionLevelMax))
if err != nil {
return nil, err
}
kind2Term := make([][]int, len(lexSpec.Modes))
for modeNum, spec := range lexSpec.Specs {
if modeNum == 0 {
kind2Term[0] = nil
continue
}
rec := make([]int, len(spec.Kinds))
for n, k := range spec.Kinds {
if n == 0 {
rec[0] = symbolNil.num().Int()
continue
}
sym, ok := gram.symbolTable.toSymbol(k.String())
if !ok {
return nil, fmt.Errorf("terminal symbol '%v' (in '%v' mode) is not found in a symbol table", k, lexSpec.Modes[modeNum])
}
rec[n] = sym.num().Int()
}
kind2Term[modeNum] = rec
}
terms, err := gram.symbolTable.getTerminalTexts()
if err != nil {
return nil, err
}
nonTerms, err := gram.symbolTable.getNonTerminalTexts()
if err != nil {
return nil, err
}
firstSet, err := genFirstSet(gram.productionSet)
if err != nil {
return nil, err
}
followSet, err := genFollowSet(gram.productionSet, firstSet)
if err != nil {
return nil, err
}
lr0, err := genLR0Automaton(gram.productionSet, gram.augmentedStartSymbol)
if err != nil {
return nil, err
}
tab, err := genSLRParsingTable(lr0, gram.productionSet, followSet, len(terms), len(nonTerms))
if err != nil {
return nil, err
}
action := make([]int, len(tab.actionTable))
for i, e := range tab.actionTable {
action[i] = int(e)
}
goTo := make([]int, len(tab.goToTable))
for i, e := range tab.goToTable {
goTo[i] = int(e)
}
lhsSyms := make([]int, len(gram.productionSet.getAllProductions())+1)
altSymCounts := make([]int, len(gram.productionSet.getAllProductions())+1)
for _, p := range gram.productionSet.getAllProductions() {
lhsSyms[p.num] = p.lhs.num().Int()
altSymCounts[p.num] = p.rhsLen
}
return &spec.CompiledGrammar{
LexicalSpecification: &spec.LexicalSpecification{
Lexer: "maleeni",
Maleeni: &spec.Maleeni{
Spec: lexSpec,
KindToTerminal: kind2Term,
},
},
ParsingTable: &spec.ParsingTable{
Action: action,
GoTo: goTo,
StateCount: tab.stateCount,
InitialState: tab.InitialState.Int(),
StartProduction: productionNumStart.Int(),
LHSSymbols: lhsSyms,
AlternativeSymbolCounts: altSymCounts,
Terminals: terms,
TerminalCount: tab.terminalCount,
NonTerminals: nonTerms,
NonTerminalCount: tab.nonTerminalCount,
EOFSymbol: symbolEOF.num().Int(),
},
}, nil
}
|
