From f691b5cb74492b97cc4adc9d02bf39633e768503 Mon Sep 17 00:00:00 2001
From: Ryo Nihei <nihei.dev@gmail.com>
Date: Mon, 13 Sep 2021 00:40:02 +0900
Subject: Add maleeni-go command

maleeni-go generates a lexer that recognizes a specific lexical specification.
---
 cmd/maleeni-go/generate.go | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 cmd/maleeni-go/generate.go

(limited to 'cmd/maleeni-go/generate.go')

diff --git a/cmd/maleeni-go/generate.go b/cmd/maleeni-go/generate.go
new file mode 100644
index 0000000..d37defd
--- /dev/null
+++ b/cmd/maleeni-go/generate.go
@@ -0,0 +1,68 @@
+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
+}{}
+
+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 > lexer.go`,
+	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) (retErr error) {
+	clspec, err := readCompiledLexSpec(args[0])
+	if err != nil {
+		return fmt.Errorf("Cannot read a compiled lexical specification: %w", err)
+	}
+
+	return driver.GenLexer(clspec, *generateFlags.pkgName)
+}
+
+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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