Add markdown support

go.mod

@@ -7,6 +7,7 @@ require (
 	git.tebibyte.media/sashakoshka/go-service v0.1.1
 	git.tebibyte.media/sashakoshka/goutil v0.6.0
 	github.com/Masterminds/sprig/v3 v3.3.0
+	github.com/yuin/goldmark v1.7.8
 )
 
 require (

go.sum

@@ -40,6 +40,8 @@ github.com/spf13/cast v1.7.0 h1:ntdiHjuueXFgm5nzDRdOS4yfT43P5Fnud6DH50rz/7w=
 github.com/spf13/cast v1.7.0/go.mod h1:ancEpBxwJDODSW/UG4rDrAqiKolqNNh2DX3mk86cAdo=
 github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+github.com/yuin/goldmark v1.7.8 h1:iERMLn0/QJeHFhxSt3p6PeN9mGnvIKSpG9YYorDMnic=
+github.com/yuin/goldmark v1.7.8/go.mod h1:uzxRWxtg69N339t3louHJ7+O03ezfj6PlliRlaOzY1E=
 golang.org/x/crypto v0.26.0 h1:RrRspgV4mU+YwB4FYnuBoKsUapNIL5cohGAmSH3azsw=
 golang.org/x/crypto v0.26.0/go.mod h1:GY7jblb9wI+FOo5y8/S2oY4zWP07AkOJ4+jxCqdqn54=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

providers/all.go

@@ -1,13 +1,15 @@
 package providers
 
 import "git.tebibyte.media/sashakoshka/step"
-import fpos    "git.tebibyte.media/sashakoshka/step/providers/os"
-import fpsprig "git.tebibyte.media/sashakoshka/step/providers/sprig"
+import fpos       "git.tebibyte.media/sashakoshka/step/providers/os"
+import fpsprig    "git.tebibyte.media/sashakoshka/step/providers/sprig"
+import fpmarkdown "git.tebibyte.media/sashakoshka/step/providers/markdown"
 
 // All returns a slice of all providers defined in sub-packages.
 func All () []step.FuncProvider {
 	return []step.FuncProvider {
-		new(fpsprig.Provider),
 		new(fpos.Provider),
+		new(fpsprig.Provider),
+		new(fpmarkdown.Provider),
 	}
 }

providers/markdown/markdown.go

@@ -0,0 +1,50 @@
+package markdown
+
+import "fmt"
+import "bytes"
+import "strings"
+import "html/template"
+import "github.com/yuin/goldmark"
+import "github.com/yuin/goldmark/parser"
+import "git.tebibyte.media/sashakoshka/step"
+
+var _ step.FuncProvider = new(Provider)
+
+// Provider provides Markdown functions.
+type Provider struct {
+	// Options contains parse options that are passed to the converter.
+	Options []parser.ParseOption
+}
+
+// FuncMap fulfills the step.FuncProvider interface.
+func (this *Provider) FuncMap () template.FuncMap {
+	stat := &state {
+		options: this.Options,
+	}
+	return template.FuncMap {
+		"markdown": stat.funcMarkdown,
+	}
+}
+
+type state struct {
+	options []parser.ParseOption
+}
+
+func (this *state) funcMarkdown (input any) (template.HTML, error) {
+	builder := strings.Builder { }
+	err := goldmark.Convert(toBytes(input), &builder, this.options...)
+	if err != nil { return "", nil }
+	return template.HTML(builder.String()), nil
+}
+
+func toBytes (data any) []byte {
+	switch data := data.(type) {
+	case []byte:        return data
+	case string:        return []byte(data)
+	case template.HTML: return []byte(data)
+	default:
+		buffer := bytes.Buffer { }
+		fmt.Fprint(&buffer, data)
+		return buffer.Bytes()
+	}
+}