Add markdown command to transpiler

cmd/transpile/main.go

@@ -16,6 +16,7 @@ import (
 
 // T represents the state of things
 type T struct {
+	Stdin  io.Reader
 	Stdout io.Writer
 	Stderr io.Writer
 	Args   []string
@@ -42,6 +43,7 @@ func usage(w io.Writer) {
 	fmt.Fprintln(w, " puzzle: Print puzzle JSON")
 	fmt.Fprintln(w, " file: Open a file for a puzzle")
 	fmt.Fprintln(w, " answer: Check correctness of an answer")
+	fmt.Fprintln(w, " markdown: Format stdin with markdown")
 }
 
 // ParseArgs parses arguments and runs the appropriate action.
@@ -71,6 +73,8 @@ func (t *T) ParseArgs() (Command, error) {
 	case "answer":
 		cmd = t.CheckAnswer
 		flags.StringVar(&t.answer, "answer", "", "Answer to check")
+	case "markdown":
+		cmd = t.Markdown
 	case "help":
 		usage(t.Stderr)
 		return nothing, nil
@@ -185,6 +189,11 @@ func (t *T) CheckAnswer() error {
 	return err
 }
 
+// Markdown runs stdin through a Markdown engine
+func (t *T) Markdown() error {
+	return transpile.Markdown(t.Stdin, t.Stdout)
+}
+
 func main() {
 	t := &T{
 		Stdout: os.Stdout,

cmd/transpile/main_test.go

@@ -51,9 +51,11 @@ func (tp T) Run(args ...string) error {
 }
 
 func TestTranspilerEverything(t *testing.T) {
+	stdin := new(bytes.Buffer)
 	stdout := new(bytes.Buffer)
 	stderr := new(bytes.Buffer)
 	tp := T{
+		Stdin:  stdin,
 		Stdout: stdout,
 		Stderr: stderr,
 		BaseFs: newTestFs(),
@@ -94,6 +96,15 @@ func TestTranspilerEverything(t *testing.T) {
 		t.Error("Answer validation failed", stdout.String())
 	}
 
+	stdout.Reset()
+	stdin.Reset()
+	stdin.WriteString("text *emphasized* text")
+	if err := tp.Run("markdown"); err != nil {
+		t.Error(err)
+	}
+	if stdout.String() != "<p>text <em>emphasized</em> text</p>\n" {
+		t.Error("Markdown conversion failed", stdout.String())
+	}
 }
 
 func TestMothballs(t *testing.T) {
@@ -165,9 +176,11 @@ func TestMothballs(t *testing.T) {
 }
 
 func TestFilesystem(t *testing.T) {
+	stdin := new(bytes.Buffer)
 	stdout := new(bytes.Buffer)
 	stderr := new(bytes.Buffer)
 	tp := T{
+		Stdin:  stdin,
 		Stdout: stdout,
 		Stderr: stderr,
 		BaseFs: afero.NewOsFs(),

pkg/transpile/markdown.go

@@ -0,0 +1,29 @@
+package transpile
+
+import (
+	"io"
+	"io/ioutil"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/renderer/html"
+)
+
+// Markdown formats the provided bytes using whatever Markdown engine we're currently using.
+func Markdown(input io.Reader, output io.Writer) error {
+	md := goldmark.New(
+		goldmark.WithExtensions(
+			extension.Table,
+			extension.DefinitionList,
+		),
+		goldmark.WithRendererOptions(
+			html.WithUnsafe(),
+		),
+	)
+	buf, err := ioutil.ReadAll(input)
+	if err != nil {
+		return err
+	}
+	md.Convert(buf, output)
+	return nil
+}

pkg/transpile/puzzle.go

@@ -19,9 +19,6 @@ import (
 	"time"
 
 	"github.com/spf13/afero"
-	"github.com/yuin/goldmark"
-	"github.com/yuin/goldmark/extension"
-	"github.com/yuin/goldmark/renderer/html"
 	"gopkg.in/yaml.v2"
 )
 
@@ -281,20 +278,9 @@ func (fp FsPuzzle) staticPuzzle() (StaticPuzzle, []byte, error) {
 		return static, nil, err
 	}
 
-	body := new(bytes.Buffer)
-
-	md := goldmark.New(
-		goldmark.WithExtensions(
-			extension.Table,
-			extension.DefinitionList,
-		),
-		goldmark.WithRendererOptions(
-			html.WithUnsafe(),
-		),
-	)
-	md.Convert(bodyBuf.Bytes(), body)
-
-	return static, body.Bytes(), err
+	html := new(bytes.Buffer)
+	err = Markdown(bodyBuf, html)
+	return static, html.Bytes(), err
 }
 
 func legacyAttachmentParser(val []string) []StaticAttachment {