parser.go

package parser

import (
	"bytes"
	"fmt"
	"strings"
)

// Parse はmarkdownをいい感じにパースして
// HTMLに変換します
func Parse(in string) (string, error) {
	if strings.HasPrefix(in, "# ") {
		body := strings.TrimSpace(in[2:])
		return fmt.Sprintf("<h1>%s</h1>", body), nil
	}
	if strings.HasPrefix(in, "- ") {
		var output string
		lines := strings.Split(in, "\n")
		for _, l := range lines {
			body := strings.TrimSpace(l[2:])
			output += fmt.Sprintf("<li>%s</li>", body)
		}
		return fmt.Sprintf("<ul>%s</ul>", output), nil
	}
	// table
	if strings.HasPrefix(in, "| ") {
		lines := strings.Split(in, "\n")
		headers := make([]string, 0)
		bodies := make([]string, 0)
		for k, v := range lines {
			if k == 0 {
				h := strings.Split(v, "|")
				for _, hh := range h {
					if hh != "" {
						headers = append(headers, hh)
					}
				}
				continue
			}
			// NOTE: table head spliter
			if k == 1 {
				if v == "| --- | --- |" {
					continue
				}
				return in, nil
			}
			// body
			if strings.HasPrefix(v, "| ") {
				b := strings.Split(v, "|")
				for _, bb := range b {
					if bb != "" {
						bodies = append(bodies, bb)
					}
				}
			}
		}

		var buf bytes.Buffer
		buf.WriteString("<table><thead>")

		buf.WriteString("<tr>")
		for _, v := range headers {
			buf.WriteString("<th>")
			buf.WriteString(strings.TrimSpace(v))
			buf.WriteString("</th>")
		}
		buf.WriteString("</tr>")

		buf.WriteString("</thead>")
		buf.WriteString("<tbody>")
		buf.WriteString("<tr>")
		for _, v := range bodies {
			buf.WriteString("<td>")
			buf.WriteString(strings.TrimSpace(v))
			buf.WriteString("</td>")
		}
		buf.WriteString("</tr>")
		buf.WriteString("</tbody>")
		buf.WriteString("</table>")

		// return `<table><thead><tr><th>foo</th><th>bar</th></tr></thead><tbody><tr><td>baz</td><td>bim</td></tr></tbody></table>`, nil
		return buf.String(), nil
	}
	return in, nil
}

parser_test.go

package parser

import "testing"

type T struct {
	in, out string
}

func TestParse(t *testing.T) {
	cases := []T{
		{"test", "test"},
		{"aaa", "aaa"},

		// headings
		{"#aaa", "#aaa"},
		{"# aaa", "<h1>aaa</h1>"},
		{"# bbb", "<h1>bbb</h1>"},
		{"# ccc    ", "<h1>ccc</h1>"},

		// list
		{"- list", "<ul><li>list</li></ul>"},
		{"- aaa", "<ul><li>aaa</li></ul>"},
		{"- aaa\n- bbb", "<ul><li>aaa</li><li>bbb</li></ul>"},
		{"- aaa\n- bbb\n- ccc", "<ul><li>aaa</li><li>bbb</li><li>ccc</li></ul>"},

		{"| foo | bar |\n", "| foo | bar |\n"},
		{
			"| foo | bar |\n| --- | --- |\n| baz | bim |",
			`<table><thead><tr><th>foo</th><th>bar</th></tr></thead><tbody><tr><td>baz</td><td>bim</td></tr></tbody></table>`},
	}
	for i, v := range cases {
		tt, _ := Parse(v.in)
		if tt != v.out {
			t.Errorf("(#%d) want %s got %s", i, v.out, tt)
		}
	}
}