Implemented headers and paragraphs

README.md

@@ -4,7 +4,8 @@ Markdown renderer.
 
 ## Features
 
-
+- Headers
+- Paragraphs
 
 ## Installation
 
@@ -15,16 +16,25 @@ go get git.akyoto.dev/go/markdown
 ## Usage
 
 ```go
+html := markdown.Render("# Header")
+fmt.Println(html)
 ```
 
 ## Tests
 
 ```
+PASS: TestEmpty
+PASS: TestParagraphs
+PASS: TestHeader
+PASS: TestCombined
+coverage: 100.0% of statements
 ```
 
 ## Benchmarks
 
-
+```
+BenchmarkSmall-12        2187232               544.9 ns/op           296 B/op          9 allocs/op
+```
 
 ## License
 

Render.go

@@ -1,6 +1,71 @@
 package markdown
 
+import (
+	"html"
+	"strings"
+)
+
+var (
+	headerStart = []string{"<h1>", "<h2>", "<h3>", "<h4>", "<h5>", "<h6>"}
+	headerEnd   = []string{"</h1>", "</h2>", "</h3>", "</h4>", "</h5>", "</h6>"}
+)
+
 // Render creates HTML from the supplied markdown text.
 func Render(markdown string) string {
-	return ""
+	var (
+		out       = strings.Builder{}
+		paragraph = strings.Builder{}
+		i         = 0
+		lineStart = 0
+	)
+
+	flush := func() {
+		if paragraph.Len() == 0 {
+			return
+		}
+
+		out.WriteString("<p>")
+		out.WriteString(html.EscapeString(paragraph.String()))
+		out.WriteString("</p>")
+		paragraph.Reset()
+	}
+
+	for {
+		if i > len(markdown) {
+			flush()
+			return out.String()
+		}
+
+		if i != len(markdown) && markdown[i] != '\n' {
+			i++
+			continue
+		}
+
+		line := markdown[lineStart:i]
+		lineStart = i + 1
+		i++
+
+		switch {
+		case strings.HasPrefix(line, "#"):
+			flush()
+			space := strings.IndexByte(line, ' ')
+
+			if space > 0 && space <= 6 {
+				out.WriteString(headerStart[space-1])
+				out.WriteString(html.EscapeString(line[space+1:]))
+				out.WriteString(headerEnd[space-1])
+			}
+
+		default:
+			if len(line) == 0 {
+				continue
+			}
+
+			if paragraph.Len() > 0 {
+				paragraph.WriteByte(' ')
+			}
+
+			paragraph.WriteString(line)
+		}
+	}
 }

Render_test.go

@@ -7,7 +7,28 @@ import (
 	"git.akyoto.dev/go/markdown"
 )
 
-func TestRender(t *testing.T) {
-	html := markdown.Render("# Hello")
-	assert.Equal(t, html, "<h1>Hello</h1>")
+func TestEmpty(t *testing.T) {
+	assert.Equal(t, markdown.Render(""), "")
+}
+
+func TestParagraphs(t *testing.T) {
+	assert.Equal(t, markdown.Render("Text"), "<p>Text</p>")
+	assert.Equal(t, markdown.Render("Text\n"), "<p>Text</p>")
+	assert.Equal(t, markdown.Render("Text\n\n"), "<p>Text</p>")
+	assert.Equal(t, markdown.Render("Text\n\n\n"), "<p>Text</p>")
+	assert.Equal(t, markdown.Render("Line 1\nLine 2"), "<p>Line 1 Line 2</p>")
+}
+
+func TestHeader(t *testing.T) {
+	assert.Equal(t, markdown.Render("# Header"), "<h1>Header</h1>")
+	assert.Equal(t, markdown.Render("## Header"), "<h2>Header</h2>")
+	assert.Equal(t, markdown.Render("### Header"), "<h3>Header</h3>")
+	assert.Equal(t, markdown.Render("#### Header"), "<h4>Header</h4>")
+	assert.Equal(t, markdown.Render("##### Header"), "<h5>Header</h5>")
+	assert.Equal(t, markdown.Render("###### Header"), "<h6>Header</h6>")
+}
+
+func TestCombined(t *testing.T) {
+	assert.Equal(t, markdown.Render("# Header\nLine 1.\nLine 2.\nLine 3."), "<h1>Header</h1><p>Line 1. Line 2. Line 3.</p>")
+	assert.Equal(t, markdown.Render("# Header 1\nLine 1.\n# Header 2\nLine 2."), "<h1>Header 1</h1><p>Line 1.</p><h1>Header 2</h1><p>Line 2.</p>")
 }

benchmarks_test.go

@@ -0,0 +1,13 @@
+package markdown_test
+
+import (
+	"testing"
+
+	"git.akyoto.dev/go/markdown"
+)
+
+func BenchmarkSmall(b *testing.B) {
+	for range b.N {
+		markdown.Render("# Header\nText.\nText.\n# Header\nText.\nText.")
+	}
+}