Introduce mermaid flowchart syntax

README.md

@@ -9,7 +9,7 @@
 # What is markdown package
 The Package markdown is a simple markdown builder in golang. The markdown package assembles Markdown using method chaining, not uses a template engine like [html/template](https://pkg.go.dev/html/template). The syntax of Markdown follows **GitHub Markdown**.
 
-The markdown package was initially developed to save test results in [nao1215/spectest](https://github.com/nao1215/spectest). Therefore, the markdown package implements the features required by spectest. For example, the markdown package supports **mermaid sequence diagrams (entity relationship diagram, sequence diagram, pie chart)**, which was a necessary feature in spectest.
+The markdown package was initially developed to save test results in [nao1215/spectest](https://github.com/nao1215/spectest). Therefore, the markdown package implements the features required by spectest. For example, the markdown package supports **mermaid sequence diagrams (entity relationship diagram, sequence diagram, flowchart, pie chart)**, which was a necessary feature in spectest.
 
 Additionally, complex code that increases the complexity of the library, such as generating nested lists, will not be added. I want to keep this library as simple as possible.
 
@@ -34,6 +34,7 @@ Additionally, complex code that increases the complexity of the library, such as
 - [x] Alerts; NOTE, TIP, IMPORTANT, CAUTION, WARNING
 - [x] mermaid sequence diagram
 - [x] mermaid entity relationship diagram
+- [x] mermaid flowchart 
 - [x] mermaid pie chart
 
 ### Features not in Markdown syntax
@@ -165,6 +166,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	md.NewMarkdown(f).
 		H1("go generate example").
@@ -366,6 +368,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	teachers := er.NewEntity(
 		"teachers",
@@ -523,6 +526,86 @@ erDiagram
 	}
 ```
 
+### Flowchart syntax
+
+```go
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/nao1215/markdown"
+	"github.com/nao1215/markdown/mermaid/flowchart"
+)
+
+//go:generate go run main.go
+
+func main() {
+	f, err := os.Create("generated.md")
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	fc := flowchart.NewFlowchart(
+		io.Discard,
+		flowchart.WithTitle("mermaid flowchart builder"),
+		flowchart.WithOrientalTopToBottom(),
+	).
+		NodeWithText("A", "Node A").
+		StadiumNode("B", "Node B").
+		SubroutineNode("C", "Node C").
+		DatabaseNode("D", "Database").
+		LinkWithArrowHead("A", "B").
+		LinkWithArrowHeadAndText("B", "D", "send original data").
+		LinkWithArrowHead("B", "C").
+		DottedLinkWithText("C", "D", "send filtered data").
+		String()
+
+	err = markdown.NewMarkdown(f).
+		H2("Flowchart").
+		CodeBlocks(markdown.SyntaxHighlightMermaid, fc).
+		Build()
+
+	if err != nil {
+		panic(err)
+	}
+}
+```
+
+Plain text output: [markdown is here](./doc/flowchart/generated.md)
+````
+## Flowchart
+```mermaid
+---
+title: mermaid flowchart builder
+---
+flowchart TB
+	A["Node A"]
+	B(["Node B"])
+	C[["Node C"]]
+	D[("Database")]
+	A-->B
+	B-->|"send original data"|D
+	B-->C
+	C-. "send filtered data" .-> D
+```
+````
+
+Mermaid output:
+```mermaid
+flowchart TB
+	A["Node A"]
+	B(["Node B"])
+	C[["Node C"]]
+	D[("Database")]
+	A-->B
+	B-->|"send original data"|D
+	B-->C
+	C-. "send filtered data" .-> D
+```
+
 ### Pie chart syntax
 
 ```go
@@ -543,6 +626,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	chart := piechart.NewPieChart(
 		io.Discard,

doc/alert/main.go

@@ -16,6 +16,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	if err := md.NewMarkdown(f).
 		H1("Alert example").

doc/badge/main.go

@@ -16,6 +16,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	if err := md.NewMarkdown(f).
 		H1("badge example").

doc/er/main.go

@@ -17,6 +17,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	teachers := er.NewEntity(
 		"teachers",

doc/flowchart/generated.md

@@ -0,0 +1,15 @@
+## Flowchart
+```mermaid
+---
+title: mermaid flowchart builder
+---
+flowchart TB
+	A["Node A"]
+	B(["Node B"])
+	C[["Node C"]]
+	D[("Database")]
+	A-->B
+	B-->|"send original data"|D
+	B-->C
+	C-. "send filtered data" .-> D
+```

doc/flowchart/main.go

@@ -0,0 +1,46 @@
+//go:build linux || darwin
+
+// Package main is generating flowchart.
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/nao1215/markdown"
+	"github.com/nao1215/markdown/mermaid/flowchart"
+)
+
+//go:generate go run main.go
+
+func main() {
+	f, err := os.Create("generated.md")
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	fc := flowchart.NewFlowchart(
+		io.Discard,
+		flowchart.WithTitle("mermaid flowchart builder"),
+		flowchart.WithOrientalTopToBottom(),
+	).
+		NodeWithText("A", "Node A").
+		StadiumNode("B", "Node B").
+		SubroutineNode("C", "Node C").
+		DatabaseNode("D", "Database").
+		LinkWithArrowHead("A", "B").
+		LinkWithArrowHeadAndText("B", "D", "send original data").
+		LinkWithArrowHead("B", "C").
+		DottedLinkWithText("C", "D", "send filtered data").
+		String()
+
+	err = markdown.NewMarkdown(f).
+		H2("Flowchart").
+		CodeBlocks(markdown.SyntaxHighlightMermaid, fc).
+		Build()
+
+	if err != nil {
+		panic(err)
+	}
+}

doc/generate/main.go

@@ -16,6 +16,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	if err := md.NewMarkdown(f).
 		H1("go generate example").

doc/piechart/main.go

@@ -18,6 +18,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	chart := piechart.NewPieChart(
 		io.Discard,

doc/sequence/main.go

@@ -18,6 +18,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	defer f.Close()
 
 	diagram := sequence.NewDiagram(io.Discard).
 		Participant("Sophia").

internal/lf.go

@@ -0,0 +1,12 @@
+// Package internal package is used to store the internal implementation of the mermaid package.
+package internal
+
+import "runtime"
+
+// LineFeed return line feed for current OS.
+func LineFeed() string {
+	if runtime.GOOS == "windows" {
+		return "\r\n"
+	}
+	return "\n"
+}

internal/lf_test.go

@@ -0,0 +1,28 @@
+// Package internal package is used to store the internal implementation of the mermaid package.
+package internal
+
+import (
+	"runtime"
+	"testing"
+)
+
+func TestLineFeed(t *testing.T) {
+	t.Parallel()
+
+	t.Run("should return line feed for current OS", func(t *testing.T) {
+		t.Parallel()
+
+		got := LineFeed()
+
+		switch runtime.GOOS {
+		case "windows":
+			if got != "\r\n" {
+				t.Errorf("expected \\r\\n, but got %s", got)
+			}
+		default:
+			if got != "\n" {
+				t.Errorf("expected \\n, but got %s", got)
+			}
+		}
+	})
+}

markdown.go

@@ -4,9 +4,9 @@ package markdown
 import (
 	"fmt"
 	"io"
-	"runtime"
 	"strings"
 
+	"github.com/nao1215/markdown/internal"
 	"github.com/olekukonko/tablewriter"
 )
 
@@ -126,7 +126,7 @@ func NewMarkdown(w io.Writer) *Markdown {
 
 // String returns markdown text.
 func (m *Markdown) String() string {
-	return strings.Join(m.body, lineFeed())
+	return strings.Join(m.body, internal.LineFeed())
 }
 
 // Error returns error.
@@ -238,7 +238,8 @@ func (m *Markdown) H6f(format string, args ...interface{}) *Markdown {
 func (m *Markdown) Details(summary, text string) *Markdown {
 	m.body = append(
 		m.body,
-		fmt.Sprintf("<details><summary>%s</summary>%s%s%s</details>", summary, lineFeed(), text, lineFeed()))
+		fmt.Sprintf("<details><summary>%s</summary>%s%s%s</details>",
+			summary, internal.LineFeed(), text, internal.LineFeed()))
 	return m
 }
 
@@ -288,7 +289,7 @@ func (m *Markdown) CheckBox(set []CheckBoxSet) *Markdown {
 // Blockquote is markdown blockquote.
 // If you set text "Hello", it will be converted to "> Hello".
 func (m *Markdown) Blockquote(text string) *Markdown {
-	lines := strings.Split(text, lineFeed())
+	lines := strings.Split(text, internal.LineFeed())
 	for _, line := range lines {
 		m.body = append(m.body, fmt.Sprintf("> %s", line))
 	}
@@ -302,7 +303,7 @@ func (m *Markdown) Blockquote(text string) *Markdown {
 // ```".
 func (m *Markdown) CodeBlocks(lang SyntaxHighlight, text string) *Markdown {
 	m.body = append(m.body,
-		fmt.Sprintf("```%s%s%s%s```", lang, lineFeed(), text, lineFeed()))
+		fmt.Sprintf("```%s%s%s%s```", lang, internal.LineFeed(), text, internal.LineFeed()))
 	return m
 }
 
@@ -345,7 +346,7 @@ func (m *Markdown) Table(t TableSet) *Markdown {
 
 	buf := &strings.Builder{}
 	table := tablewriter.NewWriter(buf)
-	table.SetNewLine(lineFeed())
+	table.SetNewLine(internal.LineFeed())
 	table.SetBorders(tablewriter.Border{Left: true, Top: false, Right: true, Bottom: false})
 	table.SetCenterSeparator("|")
 	table.SetHeader(t.Header)
@@ -379,7 +380,7 @@ func (m *Markdown) CustomTable(t TableSet, options TableOptions) *Markdown {
 
 	buf := &strings.Builder{}
 	table := tablewriter.NewWriter(buf)
-	table.SetNewLine(lineFeed())
+	table.SetNewLine(internal.LineFeed())
 	table.SetBorders(tablewriter.Border{Left: true, Top: false, Right: true, Bottom: false})
 	table.SetCenterSeparator("|")
 	table.SetAutoWrapText(options.AutoWrapText)
@@ -401,11 +402,3 @@ func (m *Markdown) LF() *Markdown {
 	m.body = append(m.body, "  ")
 	return m
 }
-
-// lineFeed return line feed for current OS.
-func lineFeed() string {
-	if runtime.GOOS == "windows" {
-		return "\r\n"
-	}
-	return "\n"
-}