Re-wrote from scratch in Golang

- Re-implemented the project in Golang, and deprecated Python entirely
- Implemented several new, long-requested features
- Refactored cheatsheets into a separate repository

internal/sheet/sheet.go

@@ -0,0 +1,64 @@
+package sheet
+
+import (
+	"fmt"
+	"io/ioutil"
+	"sort"
+	"strings"
+
+	"github.com/tj/front"
+)
+
+// frontmatter is an un-exported helper struct used in parsing cheatsheets
+type frontmatter struct {
+	Tags   []string
+	Syntax string
+}
+
+// Sheet encapsulates sheet information
+type Sheet struct {
+	Title    string
+	Path     string
+	Text     string
+	Tags     []string
+	Syntax   string
+	ReadOnly bool
+}
+
+// New initializes a new Sheet
+func New(
+	title string,
+	path string,
+	tags []string,
+	readOnly bool,
+) (Sheet, error) {
+
+	// read the cheatsheet file
+	markdown, err := ioutil.ReadFile(path)
+	if err != nil {
+		return Sheet{}, fmt.Errorf("failed to read file: %s, %v", path, err)
+	}
+
+	// parse the front-matter
+	var fm frontmatter
+	text, err := front.Unmarshal(markdown, &fm)
+	if err != nil {
+		return Sheet{}, fmt.Errorf("failed to parse front-matter: %v", err)
+	}
+
+	// merge the sheet-specific tags into the cheatpath tags
+	tags = append(tags, fm.Tags...)
+
+	// sort strings so they pretty-print nicely
+	sort.Strings(tags)
+
+	// initialize and return a sheet
+	return Sheet{
+		Title:    title,
+		Path:     path,
+		Text:     strings.TrimSpace(string(text)) + "\n",
+		Tags:     tags,
+		Syntax:   fm.Syntax,
+		ReadOnly: readOnly,
+	}, nil
+}