bug: handle hash sign inside code blocks

fixes #2

CHANGELOG.md

@@ -1,6 +1,12 @@
 # Changelog
 
 
+## v0.2.1
+
+### Fixed
+- Ignore lines matching header regex when inside code blocks
+
+
 ## v0.2.0
 
 ### Added

testdata/codeblock.md

@@ -0,0 +1,32 @@
+# Title
+An example document with code blocks containing `#` characters to verify these are not included as TOC items.
+
+## Heading 1
+
+```
+## plaintext
+### lines
+```
+
+## Heading 2
+
+```sh
+## shell
+### lines
+#### with
+##### comments
+echo "skip this"
+```
+
+## Heading 3
+
+```python
+## python
+### lines
+#### with
+##### comments
+
+if __name__ == '__main__':
+    print('skip this')
+```
+

testdata/codeblock_toc.md

@@ -0,0 +1,37 @@
+# Title
+An example document with code blocks containing `#` characters to verify these are not included as TOC items.
+
+<!---mdtoc begin--->
+* [Heading 1](#heading-1)
+* [Heading 2](#heading-2)
+* [Heading 3](#heading-3)
+<!---mdtoc end--->
+## Heading 1
+
+```
+## plaintext
+### lines
+```
+
+## Heading 2
+
+```sh
+## shell
+### lines
+#### with
+##### comments
+echo "skip this"
+```
+
+## Heading 3
+
+```python
+## python
+### lines
+#### with
+##### comments
+
+if __name__ == '__main__':
+    print('skip this')
+```
+

toc.go

@@ -58,8 +58,7 @@ func (t *Toc) Insert(b []byte, force bool) ([]byte, error) {
 	var new []byte
 	buf := bytes.NewBuffer(new)
 
-	inOld := false
-	newAdded := false
+	var inOld, newAdded bool
 
 	r := bytes.NewReader(b)
 	scanner := bufio.NewScanner(r)
@@ -105,9 +104,28 @@ func (t *Toc) Insert(b []byte, force bool) ([]byte, error) {
 func New(b []byte) (*Toc, error) {
 	toc := Toc{}
 
+	var inCodeBlock bool
+
 	r := bytes.NewReader(b)
 	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
+
+		// handle code blocks to ensure `#` are not captured as headings
+		// begin code block, set flag and skip
+		if strings.HasPrefix(scanner.Text(), "```") && !inCodeBlock {
+			inCodeBlock = true
+			continue
+		}
+		// end code block, reset flag and skip
+		if inCodeBlock && strings.HasPrefix(scanner.Text(), "```") {
+			inCodeBlock = false
+			continue
+		}
+		// code block line, skip
+		if inCodeBlock {
+			continue
+		}
+
 		m := headingRegex.FindStringSubmatch(scanner.Text())
 		if len(m) == 3 {
 			// m[0]: Full regular expression match

toc_test.go

@@ -14,6 +14,8 @@ func TestInsert(t *testing.T) {
 	specialToc, _ := os.ReadFile("testdata/special_toc.md")
 	repeat, _ := os.ReadFile("testdata/repeat.md")
 	repeatToc, _ := os.ReadFile("testdata/repeat_toc.md")
+	codeblock, _ := os.ReadFile("testdata/codeblock.md")
+	codeblockToc, _ := os.ReadFile("testdata/codeblock_toc.md")
 
 	tt := []struct {
 		name    string
@@ -25,6 +27,7 @@ func TestInsert(t *testing.T) {
 		{"basic", basic, false, basicToc, nil},
 		{"special", special, false, specialToc, nil},
 		{"repeat", repeat, false, repeatToc, nil},
+		{"code block", codeblock, false, codeblockToc, nil},
 		{"existing without force", basicToc, false, nil, ErrExistingToc},
 		{"existing with force", basicToc, true, basicToc, nil},
 	}