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package main
import (
_ "embed"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"github.com/nihei9/maleeni/driver"
"github.com/nihei9/maleeni/spec"
"github.com/spf13/cobra"
)
func Execute() error {
err := generateCmd.Execute()
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
return err
}
return nil
}
var generateFlags = struct {
pkgName *string
output *string
}{}
var generateCmd = &cobra.Command{
Use: "maleeni-go",
Short: "Generate a lexer for Go",
Long: `maleeni-go generates a lexer for Go. The lexer recognizes the lexical specification specified as the argument.`,
Example: ` maleeni-go clexspec.json`,
Args: cobra.ExactArgs(1),
RunE: runGenerate,
SilenceErrors: true,
SilenceUsage: true,
}
func init() {
generateFlags.pkgName = generateCmd.Flags().StringP("package", "p", "main", "package name")
generateFlags.output = generateCmd.Flags().StringP("output", "o", "", "output file path")
}
func runGenerate(cmd *cobra.Command, args []string) (retErr error) {
clspec, err := readCompiledLexSpec(args[0])
if err != nil {
return fmt.Errorf("Cannot read a compiled lexical specification: %w", err)
}
b, err := driver.GenLexer(clspec, *generateFlags.pkgName)
if err != nil {
return fmt.Errorf("Failed to generate a lexer: %v", err)
}
var filePath string
if *generateFlags.output != "" {
filePath = *generateFlags.output
} else {
filePath = fmt.Sprintf("%v_lexer.go", clspec.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)
}
return nil
}
func readCompiledLexSpec(path string) (*spec.CompiledLexSpec, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
data, err := ioutil.ReadAll(f)
if err != nil {
return nil, err
}
clspec := &spec.CompiledLexSpec{}
err = json.Unmarshal(data, clspec)
if err != nil {
return nil, err
}
return clspec, nil
}
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