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package main
import (
"encoding/json"
"fmt"
"io"
"os"
"github.com/nihei9/vartan/driver/lexer"
"github.com/nihei9/vartan/driver/parser"
spec "github.com/nihei9/vartan/spec/grammar"
"github.com/spf13/cobra"
)
func Execute() error {
return generateCmd.Execute()
}
var generateFlags = struct {
pkgName *string
}{}
var generateCmd = &cobra.Command{
Use: "vartan-go",
Short: "Generate a parser for Go",
Long: `vartan-go generates a parser for Go.`,
Example: ` vartan-go grammar.json`,
Args: cobra.ExactArgs(1),
RunE: runGenerate,
SilenceErrors: true,
SilenceUsage: true,
}
func init() {
generateFlags.pkgName = generateCmd.Flags().StringP("package", "p", "main", "package name")
}
func runGenerate(cmd *cobra.Command, args []string) error {
cgram, err := readCompiledGrammar(args[0])
if err != nil {
return fmt.Errorf("Cannot read a compiled grammar: %w", err)
}
{
b, err := lexer.GenLexer(cgram.Lexical, *generateFlags.pkgName)
if err != nil {
return fmt.Errorf("Failed to generate a lexer: %w", err)
}
filePath := fmt.Sprintf("%v_lexer.go", cgram.Name)
f, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return fmt.Errorf("Failed to create an output file: %v", err)
}
defer f.Close()
_, err = f.Write(b)
if err != nil {
return fmt.Errorf("Failed to write lexer source code: %v", err)
}
}
{
b, err := parser.GenParser(cgram, *generateFlags.pkgName)
if err != nil {
return fmt.Errorf("Failed to generate a parser: %w", err)
}
filePath := fmt.Sprintf("%v_parser.go", cgram.Name)
f, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return fmt.Errorf("Failed to create an output file: %v", err)
}
defer f.Close()
_, err = f.Write(b)
if err != nil {
return fmt.Errorf("Failed to write parser source code: %v", err)
}
}
{
b, err := parser.GenSemanticAction(*generateFlags.pkgName)
if err != nil {
return fmt.Errorf("Failed to generate a semantic action set: %w", err)
}
filePath := fmt.Sprintf("%v_semantic_action.go", cgram.Name)
f, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return fmt.Errorf("Failed to create an output file: %v", err)
}
defer f.Close()
_, err = f.Write(b)
if err != nil {
return fmt.Errorf("Failed to write semantic action source code: %v", err)
}
}
return nil
}
func readCompiledGrammar(path string) (*spec.CompiledGrammar, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
data, err := io.ReadAll(f)
if err != nil {
return nil, err
}
cgram := &spec.CompiledGrammar{}
err = json.Unmarshal(data, cgram)
if err != nil {
return nil, err
}
return cgram, nil
}
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