build: separate compiler and libs

compiler/cmd/internal/help/help.go

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2023 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Package help implements the “llgo help” command.
+package help
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
+	"text/template"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/goplus/llgo/compiler/cmd/internal/base"
+)
+
+// Help implements the 'help' command.
+func Help(w io.Writer, args []string) {
+	cmd := base.Llgo
+Args:
+	for i, arg := range args {
+		for _, sub := range cmd.Commands {
+			if sub.Name() == arg {
+				cmd = sub
+				continue Args
+			}
+		}
+
+		// helpSuccess is the help command using as many args as possible that would succeed.
+		helpSuccess := "llgo help"
+		if i > 0 {
+			helpSuccess += " " + strings.Join(args[:i], " ")
+		}
+		fmt.Fprintf(os.Stderr, "llgo help %s: unknown help topic. Run '%s'.\n", strings.Join(args, " "), helpSuccess)
+		os.Exit(2)
+	}
+
+	if len(cmd.Commands) > 0 {
+		PrintUsage(w, cmd)
+	} else {
+		cmd.Usage(w)
+	}
+	// not exit 2: succeeded at 'llgo help cmd'.
+}
+
+var usageTemplate = `{{.Short | trim}}
+
+Usage:
+
+	{{.UsageLine}} <command> [arguments]
+
+The commands are:
+{{range .Commands}}{{if or (.Runnable) .Commands}}
+	{{.Name | printf "%-11s"}} {{.Short}}{{end}}{{end}}
+
+Use "llgo help{{with .LongName}} {{.}}{{end}} <command>" for more information about a command.
+
+`
+
+// An errWriter wraps a writer, recording whether a write error occurred.
+type errWriter struct {
+	w   io.Writer
+	err error
+}
+
+func (w *errWriter) Write(b []byte) (int, error) {
+	n, err := w.w.Write(b)
+	if err != nil {
+		w.err = err
+	}
+	return n, err
+}
+
+// tmpl executes the given template text on data, writing the result to w.
+func tmpl(w io.Writer, text string, data interface{}) {
+	t := template.New("top")
+	t.Funcs(template.FuncMap{"trim": strings.TrimSpace, "capitalize": capitalize})
+	template.Must(t.Parse(text))
+	ew := &errWriter{w: w}
+	err := t.Execute(ew, data)
+	if ew.err != nil {
+		// I/O error writing. Ignore write on closed pipe.
+		if strings.Contains(ew.err.Error(), "pipe") {
+			os.Exit(1)
+		}
+		log.Fatalf("writing output: %v", ew.err)
+	}
+	if err != nil {
+		panic(err)
+	}
+}
+
+func capitalize(s string) string {
+	if s == "" {
+		return s
+	}
+	r, n := utf8.DecodeRuneInString(s)
+	return string(unicode.ToTitle(r)) + s[n:]
+}
+
+// PrintUsage prints usage information.
+func PrintUsage(w io.Writer, cmd *base.Command) {
+	bw := bufio.NewWriter(w)
+	tmpl(bw, usageTemplate, cmd)
+	bw.Flush()
+}