1 files changed, 158 insertions, 0 deletions
diff --git a/grammar/grammar.go b/grammar/grammar.go
new file mode 100644
index 0000000..ce0ff19
--- /dev/null
+++ b/grammar/grammar.go
@@ -0,0 +1,158 @@
+package grammar
+
+import (
+	"fmt"
+
+	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
+}