preserve init error

Makefile

@@ -118,12 +118,10 @@ cpu: cpu.out
 	go tool pprof -top cpu.out
 
 fmt: $(SOURCES)
-	@echo fmt
-	@gofmt -w -s $(SOURCES)
+	gofmt -w -s $(SOURCES)
 
 checkfmt: $(SOURCES)
-	@echo check fmt
-	@if [ "$$(gofmt -s -d $(SOURCES))" != "" ]; then false; else true; fi
+	if [ "$$(gofmt -s -d $(SOURCES))" != "" ]; then false; else true; fi
 
 vet:
 	go vet ./...

cmd/treerack/open.go

@@ -2,12 +2,12 @@ package main
 
 import (
 	"bytes"
+	"code.squareroundforest.org/arpio/treerack"
 	"flag"
+	"golang.org/x/crypto/ssh/terminal"
 	"io"
 	"io/ioutil"
 	"os"
-	"code.squareroundforest.org/arpio/treerack"
-	"golang.org/x/crypto/ssh/terminal"
 )
 
 type fileOptions struct {

cmd/treerack/show.go

@@ -1,8 +1,8 @@
 package main
 
 import (
-	"encoding/json"
 	"code.squareroundforest.org/arpio/treerack"
+	"encoding/json"
 )
 
 type showOptions struct {

syntax.go

@@ -1,10 +1,10 @@
 package treerack
 
 import (
+	"code.squareroundforest.org/arpio/treerack/self"
 	"errors"
 	"fmt"
 	"io"
-	"code.squareroundforest.org/arpio/treerack/self"
 )
 
 // if min=0&&max=0, it means min=1,max=1
@@ -18,7 +18,7 @@ type SequenceItem struct {
 type Syntax struct {
 	registry      *registry
 	initialized   bool
-	initFailed   bool
+	errInitFailed error
 	explicitRoot  bool
 	keywords      []definition
 	root          definition
@@ -52,7 +52,6 @@ type definition interface {
 
 var (
 	ErrSyntaxInitialized      = errors.New("syntax initialized")
-	ErrInitFailed             = errors.New("init failed")
 	ErrNoParsersDefined       = errors.New("no parsers defined")
 	ErrInvalidEscapeCharacter = errors.New("invalid escape character")
 	ErrMultipleRoots          = errors.New("multiple roots")
@@ -296,8 +295,8 @@ func (s *Syntax) ReadSyntax(r io.Reader) error {
 }
 
 func (s *Syntax) Init() error {
-	if s.initFailed {
-		return ErrInitFailed
+	if s.errInitFailed != nil {
+		return s.errInitFailed
 	}
 
 	if s.initialized {
@@ -324,13 +323,13 @@ func (s *Syntax) Init() error {
 
 	for i := range s.keywords {
 		if err := s.keywords[i].validate(s.registry); err != nil {
-			s.initFailed = true
+			s.errInitFailed = err
 			return err
 		}
 	}
 
 	if err := s.root.validate(s.registry); err != nil {
-		s.initFailed = true
+		s.errInitFailed = err
 		return err
 	}