fix unexported code generation

Makefile

@@ -32,6 +32,17 @@ head: $(SOURCES) fmt
 		syntaxhead.go \
 	> head.go
 	@gofmt -s -w head.go
+	go run scripts/createhead.go --exported -- \
+		char.go \
+		sequence.go \
+		choice.go \
+		idset.go \
+		results.go \
+		context.go \
+		nodehead.go \
+		syntaxhead.go \
+	> headexported.go
+	@gofmt -s -w headexported.go
 
 generate: $(SOURCES) $(PARSERS) fmt head install
 	treerack generate -export -package-name self < syntax.treerack > self/self.go.next
@@ -48,8 +59,8 @@ regenerate: $(SOURCES) $(PARSERS) fmt head install
 
 check-generate: $(SOURCES) $(PARSERS)
 	@echo checking head
-	@mv head.go head.go.backup
-	@go run scripts/createhead.go -- \
+	@mv headexported.go headexported.go.backup
+	@go run scripts/createhead.go --exported -- \
 		char.go \
 		sequence.go \
 		choice.go \
@@ -58,10 +69,10 @@ check-generate: $(SOURCES) $(PARSERS)
 		context.go \
 		nodehead.go \
 		syntaxhead.go \
-	> head.go
-	@gofmt -s -w head.go
-	@if ! diff head.go head.go.backup > /dev/null; then \
-		mv head.go.backup head.go; \
+	> headexported.go
+	@gofmt -s -w headexported.go
+	@if ! diff headexported.go headexported.go.backup > /dev/null; then \
+		mv headexported.go.backup headexported.go; \
 		echo head does not match; \
 		false; \
 	fi
@@ -77,7 +88,7 @@ check-generate: $(SOURCES) $(PARSERS)
 	fi
 
 	@echo ok
-	@mv head.go.backup head.go
+	@mv headexported.go.backup headexported.go
 	@mv self/self.go.backup self/self.go
 
 check: build $(PARSERS)

go.mod

@@ -5,6 +5,8 @@ go 1.24.6
 require golang.org/x/crypto v0.41.0
 
 require (
+	code.squareroundforest.org/arpio/notation v0.0.0-20241225183158-af3bd591a174 // indirect
+	github.com/iancoleman/strcase v0.3.0 // indirect
 	golang.org/x/sys v0.35.0 // indirect
 	golang.org/x/term v0.34.0 // indirect
 )

go.sum

@@ -1,3 +1,7 @@
+code.squareroundforest.org/arpio/notation v0.0.0-20241225183158-af3bd591a174 h1:DKMSagVY3uyRhJ4ohiwQzNnR6CWdVKLkg97A8eQGxQU=
+code.squareroundforest.org/arpio/notation v0.0.0-20241225183158-af3bd591a174/go.mod h1:ait4Fvg9o0+bq5hlxi9dAcPL5a+/sr33qsZPNpToMLY=
+github.com/iancoleman/strcase v0.3.0 h1:nTXanmYxhfFAMjZL34Ov6gkzEsSJZ5DbhxWjvSASxEI=
+github.com/iancoleman/strcase v0.3.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 golang.org/x/crypto v0.41.0 h1:WKYxWedPGCTVVl5+WHSSrOBT0O8lx32+zxmHxijgXp4=
 golang.org/x/crypto v0.41.0/go.mod h1:pO5AFd7FA68rFak7rOAGVuygIISepHftHnr8dr6+sUc=
 golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=

scripts/createhead.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
+	"github.com/iancoleman/strcase"
 	"go/ast"
 	"go/parser"
 	"go/printer"
@@ -11,11 +12,36 @@ import (
 	"io"
 	"log"
 	"os"
+	"regexp"
 	"strconv"
 	"strings"
 )
 
-func concatGo(w io.Writer, r ...io.Reader) error {
+var exportedSymbols = []string{
+	"ErrInvalidUnicodeCharacter",
+	"CommitType",
+	"None",
+	"Alias",
+	"Whitespace",
+	"NoWhitespace",
+	"Keyword",
+	"NoKeyword",
+	"FailPass",
+	"Root",
+	"Node",
+	"ParseError",
+}
+
+func unexporter() map[string]*regexp.Regexp {
+	m := make(map[string]*regexp.Regexp)
+	for _, name := range exportedSymbols {
+		m[name] = regexp.MustCompile(fmt.Sprintf("\\b%s\\b", name))
+	}
+
+	return m
+}
+
+func concatGo(w io.Writer, exported bool, r ...io.Reader) error {
 	var others []ast.Decl
 	imports := &ast.GenDecl{
 		Tok:    token.IMPORT,
@@ -74,8 +100,13 @@ func removePackage(gO string) string {
 }
 
 func main() {
-	var packageName string
+	var (
+		packageName string
+		exported    bool
+	)
+
 	flag.StringVar(&packageName, "package", "treerack", "package name of the generated code file")
+	flag.BoolVar(&exported, "exported", false, "export required symbols")
 	flag.Parse()
 
 	var files []io.Reader
@@ -90,13 +121,24 @@ func main() {
 	}
 
 	var headCode bytes.Buffer
-	if err := concatGo(&headCode, files...); err != nil {
+	if err := concatGo(&headCode, exported, files...); err != nil {
 		log.Fatalln(err)
 	}
 
 	code := headCode.String()
 	code = removePackage(code)
-	quotedCode := strconv.Quote(code)
-
-	fmt.Printf("package %s\n\n// generated with scripts/createhead.go\nconst headCode=%s", packageName, quotedCode)
+	if !exported {
+		unexp := unexporter()
+		for name, exp := range unexp {
+			code = exp.ReplaceAllString(code, strcase.ToLowerCamel(name))
+		}
+	}
+
+	quotedCode := strconv.Quote(code)
+	varName := "headCode"
+	if exported {
+		varName = "headCodeExported"
+	}
+
+	fmt.Printf("package %s\n\n// generated with scripts/createhead.go\nconst %s=%s", packageName, varName, quotedCode)
 }

syntax.go

@@ -390,7 +390,12 @@ func (s *Syntax) Generate(o GeneratorOptions, w io.Writer) error {
 	fprintln()
 
 	// generate headCode with scripts/createhead.go
-	fprint(headCode)
+	hc := headCode
+	if o.Export {
+		hc = headCodeExported
+	}
+
+	fprint(hc)
 	fprintln()
 	fprintln()