skeleton and readme

README.md

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+## md2gmi
+
+Convert Markdown to Gemini Gemini "gemtext" markup with Go.
+
+### Usage
+
+```
+Usage of ./md2gmi:
+  -in string
+        specify a .md (Markdown) file to read from, otherwise stdin (default)
+  -out string
+        specify a .gmi (gemtext) file to write to, otherwise stdout (default)
+```
+
+### Example
+
+    go get github.com/n0x1m/md2gmi
+    cat file.md | md2gmi
+    md2gmi -in file.md -out file.gmi

main.go

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+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+)
+
+func read(in string, data chan<- []byte) error {
+	if in != "" {
+		file, err := os.Open(in)
+		if err != nil {
+			return err
+		}
+		defer file.Close()
+
+		s := bufio.NewScanner(file)
+		for s.Scan() {
+			data <- s.Bytes()
+		}
+
+		return nil
+	}
+
+	s := bufio.NewScanner(os.Stdin)
+	for s.Scan() {
+		data <- s.Bytes()
+	}
+
+	return nil
+}
+
+func writer(out string) (io.Writer, error) {
+	if out != "" {
+		file, err := os.Open(out)
+		if err != nil {
+			return nil, err
+		}
+
+		return file, nil
+	}
+
+	return os.Stdout, nil
+}
+
+func write(out string, data <-chan []byte, quit chan struct{}) error {
+	w, err := writer(out)
+	if err != nil {
+		return fmt.Errorf("writer: %w", err)
+	}
+
+	NewParser(data, w, quit).Parse()
+
+	for {
+		select {
+		case <-quit:
+			return nil
+		case b := <-data:
+			fmt.Fprintf(w, string(b)+"\n")
+		}
+	}
+}
+
+func main() {
+	var in, out string
+
+	flag.StringVar(&in, "in", "", "specify a .md (Markdown) file to read from, otherwise stdin (default)")
+	flag.StringVar(&out, "out", "", "specify a .gmi (gemtext) file to write to, otherwise stdout (default)")
+	flag.Parse()
+
+	quit := make(chan struct{})
+	data := make(chan []byte)
+
+	go func() {
+		if err := read(in, data); err != nil {
+			fmt.Fprintf(os.Stderr, err.Error())
+		}
+		close(quit)
+	}()
+
+	if err := write(out, data, quit); err != nil {
+		fmt.Fprintf(os.Stderr, err.Error())
+	}
+}