From 500af457c12a8c11c4b32301f6ab324248c4ccaa Mon Sep 17 00:00:00 2001
From: Kevin Chabowski <kevin@kch42.de>
Date: Thu, 1 May 2014 14:22:15 +0200
Subject: Introduced new config file format

---
 conflang.go | 160 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 conflang.go

(limited to 'conflang.go')

diff --git a/conflang.go b/conflang.go
new file mode 100644
index 0000000..0b4a856
--- /dev/null
+++ b/conflang.go
@@ -0,0 +1,160 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+)
+
+type toktype int
+
+const (
+	tText toktype = iota
+	tNextCmd
+)
+
+type token struct {
+	Type toktype
+	Data string
+	Line int
+}
+
+func scan(r io.Reader, tokens chan<- token, errch chan<- error) {
+	emit := func(t toktype, d []byte, line int) {
+		if t == tText && len(d) == 0 {
+			return
+		}
+		tokens <- token{t, string(d), line}
+	}
+
+	err := func() error {
+		br := bufio.NewReader(r)
+
+		escaped := false
+		data := []byte{}
+		line := 1
+
+		for {
+			b, err := br.ReadByte()
+
+			switch err {
+			case nil:
+			case io.EOF:
+				return nil
+			default:
+				return ErrorAtLine{line, err}
+			}
+
+			if b == '\n' {
+				line++
+			}
+
+			if escaped {
+				data = append(data, b)
+				escaped = false
+				continue
+			}
+
+			switch b {
+			case '\\':
+				escaped = true
+			case ' ', '\t':
+				emit(tText, data, line)
+				data = data[:0]
+			case '\n':
+				emit(tText, data, line)
+				data = data[:0]
+				emit(tNextCmd, nil, line)
+			default:
+				data = append(data, b)
+			}
+		}
+
+		emit(tText, data, line)
+		emit(tNextCmd, nil, line)
+		return nil
+	}()
+
+	close(tokens)
+	errch <- err
+}
+
+type command struct {
+	Name   string
+	Params []string
+	Line   int
+}
+
+func parse(tokens <-chan token, cmds chan<- command) {
+	defer close(cmds)
+
+	startcmd := true
+	cmd := command{"", make([]string, 0), 0}
+
+	for tok := range tokens {
+		switch tok.Type {
+		case tText:
+			if startcmd {
+				cmd.Name = tok.Data
+				cmd.Line = tok.Line
+				startcmd = false
+			} else {
+				cmd.Params = append(cmd.Params, tok.Data)
+			}
+		case tNextCmd:
+			if !startcmd {
+				cmds <- cmd
+				cmd.Name = ""
+				cmd.Params = make([]string, 0)
+				startcmd = true
+			}
+		}
+	}
+}
+
+type cmdfunc func(params []string) error
+
+var commands = map[string]cmdfunc{
+	"nop": func(_ []string) error { return nil },
+}
+
+func RegisterCommand(name string, f cmdfunc) {
+	commands[name] = f
+}
+
+type ErrorAtLine struct {
+	Line int
+	Err  error
+}
+
+func (err ErrorAtLine) Error() string {
+	return fmt.Sprintf("%s (at line %d)", err.Err, err.Line)
+}
+
+type CommandNotFound string
+
+func (c CommandNotFound) Error() string {
+	return fmt.Sprintf("Command \"%s\" not found", c)
+}
+
+func RunCommands(r io.Reader) error {
+	errch := make(chan error)
+	tokens := make(chan token)
+	cmds := make(chan command)
+
+	go scan(r, tokens, errch)
+	go parse(tokens, cmds)
+
+	for cmd := range cmds {
+		f, ok := commands[cmd.Name]
+		if !ok {
+			return ErrorAtLine{cmd.Line, CommandNotFound(cmd.Name)}
+		}
+
+		if err := f(cmd.Params); err != nil {
+			return ErrorAtLine{cmd.Line, err}
+		}
+	}
+
+	return <-errch
+}
-- 
cgit v1.2.3-54-g00ecf