option to select between atx and settext header style

.gitignore

@@ -0,0 +1 @@
+build/

README.md

@@ -25,7 +25,8 @@ Usage
 usage: markdownfmt [flags] [path ...]
   -d=false: display diffs instead of rewriting files
   -l=false: list files whose formatting differs from markdownfmt's
-  -w=false: write result to (source) file instead of stdout
+  -s=false: use atx header style, if true use settext
+  -w=false: write result to (source) file instead of
 ```
 
 Editor Plugins

go.mod

@@ -1,3 +1,10 @@
 module github.com/shurcooL/markdownfmt
 
-require github.com/russross/blackfriday v1.5.3-0.20190124082335-a477dd164691
+go 1.14
+
+require (
+	github.com/mattn/go-runewidth v0.0.9
+	github.com/russross/blackfriday v1.5.3-0.20190124082335-a477dd164691
+	github.com/shurcooL/go v0.0.0-20191216061654-b114cc39af9f
+	golang.org/x/crypto v0.0.0-20200323165209-0ec3e9974c59
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/mattn/go-runewidth v0.0.9 h1:Lm995f3rfxdpd6TSmuVCHVb/QhupuXlYr8sCI/QdE+0=
+github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
+github.com/russross/blackfriday v1.5.3-0.20190124082335-a477dd164691 h1:auJkuUc4uOuZNoH9jGLvqVaDLiuCOh/LY+Qw5NBFo4I=
+github.com/russross/blackfriday v1.5.3-0.20190124082335-a477dd164691/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
+github.com/shurcooL/go v0.0.0-20191216061654-b114cc39af9f h1:gvOuVMIvQ0Ca/afBH/YBfp5f2RWb92DbAI5EjwoFLuc=
+github.com/shurcooL/go v0.0.0-20191216061654-b114cc39af9f/go.mod h1:TDJrrUr11Vxrven61rcy3hJMUqaf/CLWYhHNPmT14Lk=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200323165209-0ec3e9974c59 h1:3zb4D3T4G8jdExgVU/95+vQXfpEPiMdCaZgmGVxjNHM=
+golang.org/x/crypto v0.0.0-20200323165209-0ec3e9974c59/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

main.go

@@ -19,9 +19,10 @@ import (
 
 var (
 	// Main operation modes.
-	list   = flag.Bool("l", false, "list files whose formatting differs from markdownfmt's")
-	write  = flag.Bool("w", false, "write result to (source) file instead of stdout")
-	doDiff = flag.Bool("d", false, "display diffs instead of rewriting files")
+	list              = flag.Bool("l", false, "list files whose formatting differs from markdownfmt's")
+	write             = flag.Bool("w", false, "write result to (source) file instead of stdout")
+	doDiff            = flag.Bool("d", false, "display diffs instead of rewriting files")
+	useSetTextHeaders = flag.Bool("s", false, "use settext style headers instead of atx ones")
 
 	exitCode = 0
 )
@@ -61,7 +62,8 @@ func processFile(filename string, in io.Reader, out io.Writer, stdin bool) error
 		return terminal.IsTerminal(int(os.Stdout.Fd())) && os.Getenv("TERM") != "dumb"
 	}
 	res, err := markdown.Process(filename, src, &markdown.Options{
-		Terminal: !*list && !*write && !*doDiff && isTerminal(),
+		Terminal:          !*list && !*write && !*doDiff && isTerminal(),
+		UseSetTextHeaders: *useSetTextHeaders,
 	})
 	if err != nil {
 		return err

markdown/main.go

@@ -8,7 +8,7 @@ import (
 	"io/ioutil"
 	"strings"
 
-	"github.com/mattn/go-runewidth"
+	runewidth "github.com/mattn/go-runewidth"
 	"github.com/russross/blackfriday"
 	"github.com/shurcooL/go/indentwriter"
 )
@@ -102,24 +102,32 @@ func (*markdownRenderer) TitleBlock(out *bytes.Buffer, text []byte) {
 func (mr *markdownRenderer) Header(out *bytes.Buffer, text func() bool, level int, id string) {
 	marker := out.Len()
 	doubleSpace(out)
+	if mr.opt.UseSetTextHeaders == true {
+		if level >= 3 {
+			fmt.Fprint(out, strings.Repeat("#", level), " ")
+		}
 
-	if level >= 3 {
-		fmt.Fprint(out, strings.Repeat("#", level), " ")
-	}
-
-	textMarker := out.Len()
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
+		textMarker := out.Len()
+		if !text() {
+			out.Truncate(marker)
+			return
+		}
 
-	switch level {
-	case 1:
-		len := mr.stringWidth(out.String()[textMarker:])
-		fmt.Fprint(out, "\n", strings.Repeat("=", len))
-	case 2:
-		len := mr.stringWidth(out.String()[textMarker:])
-		fmt.Fprint(out, "\n", strings.Repeat("-", len))
+		switch level {
+		case 1:
+			len := mr.stringWidth(out.String()[textMarker:])
+			fmt.Fprint(out, "\n", strings.Repeat("=", len))
+		case 2:
+			len := mr.stringWidth(out.String()[textMarker:])
+			fmt.Fprint(out, "\n", strings.Repeat("-", len))
+		}
+	} else {
+		fmt.Fprint(out, strings.Repeat("#", level), " ")
+		// textMarker := out.Len()
+		if !text() {
+			out.Truncate(marker)
+			return
+		}
 	}
 	out.WriteString("\n")
 }
@@ -470,7 +478,8 @@ func NewRenderer(opt *Options) blackfriday.Renderer {
 // Options specifies options for formatting.
 type Options struct {
 	// Terminal specifies if ANSI escape codes are emitted for styling.
-	Terminal bool
+	Terminal          bool
+	UseSetTextHeaders bool
 }
 
 // Process formats Markdown.