1 files changed, 0 insertions, 145 deletions
diff --git a/grammar/follow.go b/grammar/follow.go
deleted file mode 100644
index 67e5f70..0000000
--- a/grammar/follow.go
+++ /dev/null
@@ -1,145 +0,0 @@
-package grammar
-
-import (
-	"fmt"
-)
-
-type followEntry struct {
-	symbols map[symbol]struct{}
-	eof     bool
-}
-
-func newFollowEntry() *followEntry {
-	return &followEntry{
-		symbols: map[symbol]struct{}{},
-		eof:     false,
-	}
-}
-
-func (e *followEntry) add(sym symbol) bool {
-	if _, ok := e.symbols[sym]; ok {
-		return false
-	}
-	e.symbols[sym] = struct{}{}
-	return true
-}
-
-func (e *followEntry) addEOF() bool {
-	if !e.eof {
-		e.eof = true
-		return true
-	}
-	return false
-}
-
-func (e *followEntry) merge(fst *firstEntry, flw *followEntry) bool {
-	changed := false
-
-	if fst != nil {
-		for sym := range fst.symbols {
-			added := e.add(sym)
-			if added {
-				changed = true
-			}
-		}
-	}
-
-	if flw != nil {
-		for sym := range flw.symbols {
-			added := e.add(sym)
-			if added {
-				changed = true
-			}
-		}
-		if flw.eof {
-			added := e.addEOF()
-			if added {
-				changed = true
-			}
-		}
-	}
-
-	return changed
-}
-
-type followSet struct {
-	set map[symbol]*followEntry
-}
-
-func newFollow(prods *productionSet) *followSet {
-	flw := &followSet{
-		set: map[symbol]*followEntry{},
-	}
-	for _, prod := range prods.getAllProductions() {
-		if _, ok := flw.set[prod.lhs]; ok {
-			continue
-		}
-		flw.set[prod.lhs] = newFollowEntry()
-	}
-	return flw
-}
-
-func (flw *followSet) find(sym symbol) (*followEntry, error) {
-	e, ok := flw.set[sym]
-	if !ok {
-		return nil, fmt.Errorf("an entry of FOLLOW was not found; symbol: %s", sym)
-	}
-	return e, nil
-}
-
-func genFollowSet(prods *productionSet, first *firstSet) (*followSet, error) {
-	ntsyms := map[symbol]struct{}{}
-	for _, prod := range prods.getAllProductions() {
-		if _, ok := ntsyms[prod.lhs]; ok {
-			continue
-		}
-		ntsyms[prod.lhs] = struct{}{}
-	}
-
-	follow := newFollow(prods)
-	for {
-		more := false
-		for ntsym := range ntsyms {
-			e, err := follow.find(ntsym)
-			if err != nil {
-				return nil, err
-			}
-			if ntsym.isStart() {
-				changed := e.addEOF()
-				if changed {
-					more = true
-				}
-			}
-			for _, prod := range prods.getAllProductions() {
-				for i, sym := range prod.rhs {
-					if sym != ntsym {
-						continue
-					}
-					fst, err := first.find(prod, i+1)
-					if err != nil {
-						return nil, err
-					}
-					changed := e.merge(fst, nil)
-					if changed {
-						more = true
-					}
-					if fst.empty {
-						flw, err := follow.find(prod.lhs)
-						if err != nil {
-							return nil, err
-						}
-						changed := e.merge(nil, flw)
-						if changed {
-							more = true
-						}
-					}
-				}
-			}
-		}
-		if !more {
-			break
-		}
-	}
-
-	return follow, nil
-}