1 files changed, 0 insertions, 148 deletions
diff --git a/src/urubu/grammar/first.go b/src/urubu/grammar/first.go
deleted file mode 100644
index 6443bcf..0000000
--- a/src/urubu/grammar/first.go
+++ /dev/null
@@ -1,148 +0,0 @@
-package grammar
-
-import (
-	"fmt"
-
-	"urubu/grammar/symbol"
-)
-
-type firstEntry struct {
-	symbols map[symbol.Symbol]struct{}
-	empty   bool
-}
-
-func newFirstEntry() *firstEntry {
-	return &firstEntry{
-		symbols: map[symbol.Symbol]struct{}{},
-		empty:   false,
-	}
-}
-
-func (e *firstEntry) add(sym symbol.Symbol) bool {
-	if _, ok := e.symbols[sym]; ok {
-		return false
-	}
-	e.symbols[sym] = struct{}{}
-	return true
-}
-
-func (e *firstEntry) addEmpty() bool {
-	if !e.empty {
-		e.empty = true
-		return true
-	}
-	return false
-}
-
-func (e *firstEntry) mergeExceptEmpty(target *firstEntry) bool {
-	if target == nil {
-		return false
-	}
-	changed := false
-	for sym := range target.symbols {
-		added := e.add(sym)
-		if added {
-			changed = true
-		}
-	}
-	return changed
-}
-
-type firstSet struct {
-	set map[symbol.Symbol]*firstEntry
-}
-
-func newFirstSet(prods *productionSet) *firstSet {
-	fst := &firstSet{
-		set: map[symbol.Symbol]*firstEntry{},
-	}
-	for _, prod := range prods.getAllProductions() {
-		if _, ok := fst.set[prod.lhs]; ok {
-			continue
-		}
-		fst.set[prod.lhs] = newFirstEntry()
-	}
-
-	return fst
-}
-
-func (fst *firstSet) find(prod *production, head int) (*firstEntry, error) {
-	entry := newFirstEntry()
-	if prod.rhsLen <= head {
-		entry.addEmpty()
-		return entry, nil
-	}
-	for _, sym := range prod.rhs[head:] {
-		if sym.IsTerminal() {
-			entry.add(sym)
-			return entry, nil
-		}
-
-		e := fst.findBySymbol(sym)
-		if e == nil {
-			return nil, fmt.Errorf("an entry of FIRST was not found; symbol: %s", sym)
-		}
-		for s := range e.symbols {
-			entry.add(s)
-		}
-		if !e.empty {
-			return entry, nil
-		}
-	}
-	entry.addEmpty()
-	return entry, nil
-}
-
-func (fst *firstSet) findBySymbol(sym symbol.Symbol) *firstEntry {
-	return fst.set[sym]
-}
-
-type firstComContext struct {
-	first *firstSet
-}
-
-func newFirstComContext(prods *productionSet) *firstComContext {
-	return &firstComContext{
-		first: newFirstSet(prods),
-	}
-}
-
-func genFirstSet(prods *productionSet) (*firstSet, error) {
-	cc := newFirstComContext(prods)
-	for {
-		more := false
-		for _, prod := range prods.getAllProductions() {
-			e := cc.first.findBySymbol(prod.lhs)
-			changed, err := genProdFirstEntry(cc, e, prod)
-			if err != nil {
-				return nil, err
-			}
-			if changed {
-				more = true
-			}
-		}
-		if !more {
-			break
-		}
-	}
-	return cc.first, nil
-}
-
-func genProdFirstEntry(cc *firstComContext, acc *firstEntry, prod *production) (bool, error) {
-	if prod.isEmpty() {
-		return acc.addEmpty(), nil
-	}
-
-	for _, sym := range prod.rhs {
-		if sym.IsTerminal() {
-			return acc.add(sym), nil
-		}
-
-		e := cc.first.findBySymbol(sym)
-		changed := acc.mergeExceptEmpty(e)
-		if !e.empty {
-			return changed, nil
-		}
-	}
-	return acc.addEmpty(), nil
-}