allow indentation in fences

stefanfritsch · Jan 16, 2023 · 4ae084e · 4ae084e
1 parent df7461d
commit 4ae084e
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Showing 3 changed files with 141 additions and 14 deletions.
diff --git a/gen_random_string.go b/gen_random_string.go
@@ -0,0 +1,13 @@
+package fences
+
+import "math/rand"
+
+const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+func genRandomString(n int) string {
+	bytes := make([]byte, n)
+	for i := range bytes {
+		bytes[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(bytes)
+}
diff --git a/parser.go b/parser.go
@@ -19,10 +19,12 @@ func NewFencedContainerParser() parser.BlockParser {
 }
 
 type fenceData struct {
-	char   byte
-	indent int
-	length int
-	node   ast.Node
+	char              byte     // Currently, this is always ":"
+	indent            int      // The indentation of the opening (and closing) tags (:::{})
+	length            int      // The length of the fence, e.g. is it ::: or ::::?
+	node              ast.Node // The node of the fence
+	contentIndent     int      // The indentation of the content relative to the previous fenced block. The first line of the content is taken as its indentation. If you want a fence with just a code block you need to use backticks
+	contentHasStarted bool     // Only used as an indicator if contentIndent has been set already
 }
 
 var fencedContainerInfoKey = parser.NewContextKey()
@@ -47,7 +49,9 @@ func (b *fencedContainerParser) Open(parent ast.Node, reader text.Reader, pc par
 		return nil, parser.NoChildren
 	}
 
-	node := NewFencedContainer()
+	// ========================================================================== //
+	// 	Without attributes we return
+
 	if i >= len(line)-1 {
 		// If there are no attributes we can't create a div because we won't know
 		// if a ":::" ends the last fenced container or opens a new one
@@ -65,23 +69,38 @@ func (b *fencedContainerParser) Open(parent ast.Node, reader text.Reader, pc par
 		return nil, parser.NoChildren
 	}
 
+	// ========================================================================== //
+	// 	With attributes we construct the node
+
 	reader.Advance(left)
-	attrs, ok := parser.ParseAttributes(reader)
+	node := NewFencedContainer()
+
+	fenceID := genRandomString(24)
+	node.SetAttributeString("data-fenceid", []byte(fenceID))
 
+	attrs, ok := parser.ParseAttributes(reader)
 	if ok {
 		for _, attr := range attrs {
 			node.SetAttribute(attr.Name, attr.Value)
 		}
 	}
 
-	fdata := &fenceData{fenceChar, findent, oFenceLength, node}
-	var fdataMap []*fenceData
+	fdata := &fenceData{
+		char:              fenceChar,
+		indent:            findent,
+		length:            oFenceLength,
+		node:              node,
+		contentIndent:     0,
+		contentHasStarted: false,
+	}
+
+	var fdataMap map[string]*fenceData
 
 	if oldData := pc.Get(fencedContainerInfoKey); oldData != nil {
-		fdataMap = oldData.([]*fenceData)
-		fdataMap = append(fdataMap, fdata)
+		fdataMap = oldData.(map[string]*fenceData)
+		fdataMap[fenceID] = fdata
 	} else {
-		fdataMap = []*fenceData{fdata}
+		fdataMap = map[string]*fenceData{fenceID: fdata}
 	}
 	pc.Set(fencedContainerInfoKey, fdataMap)
 
@@ -98,15 +117,30 @@ func (b *fencedContainerParser) Open(parent ast.Node, reader text.Reader, pc par
 
 func (b *fencedContainerParser) Continue(node ast.Node, reader text.Reader, pc parser.Context) parser.State {
 	rawdata := pc.Get(fencedContainerInfoKey)
-	fdataMap := rawdata.([]*fenceData)
-	fdata := fdataMap[len(fdataMap)-1]
+	fdataMap := rawdata.(map[string]*fenceData)
+
+	rawFenceID, ok := node.AttributeString("data-fenceid")
+	if !ok {
+		// huhu: don't panic in production
+		panic("fenceID is missing")
+	}
+	fenceID := string(rawFenceID.([]byte))
+	fdata := fdataMap[fenceID]
 
 	line, segment := reader.PeekLine()
 	w, pos := util.IndentWidth(line, reader.LineOffset())
 
+	if !fdata.contentHasStarted && !util.IsBlank(line[pos:]) {
+		fdata.contentHasStarted = true
+		fdata.contentIndent = w
+
+		fdataMap[fenceID] = fdata
+		pc.Set(fencedContainerInfoKey, fdataMap)
+	}
+
 	if close, newline := b.closes(line, segment, w, pos, node, fdata); close {
 		reader.Advance(segment.Stop - segment.Start - newline + segment.Padding)
-		fdataMap = fdataMap[:len(fdataMap)-1]
+		delete(fdataMap, fenceID)
 
 		if len(fdataMap) == 0 {
 			return parser.Close
@@ -116,6 +150,10 @@ func (b *fencedContainerParser) Continue(node ast.Node, reader text.Reader, pc p
 		}
 	}
 
+	if fdata.contentIndent > 0 {
+		reader.Advance(fdata.contentIndent)
+	}
+
 	return parser.Continue | parser.HasChildren
 }
 

diff --git a/tests/indent_test.go b/tests/indent_test.go
@@ -0,0 +1,76 @@
+package fences_test
+
+import (
+	"os"
+	"strings"
+
+	fences "github.com/stefanfritsch/goldmark-fences"
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/text"
+)
+
+func Example_indent() {
+	srcString := strings.ReplaceAll(`
+## Hello
+
+This is outside
+
+§§§
+this is unindented code
+§§§
+
+    this is indented code
+
+:::{#big-div .add-border}
+
+    This is indented
+    
+    :::{.background-green .font-big}
+        ## This is indented within indented
+        
+        §§§
+        this is unindented code in an indented block
+        §§§
+        
+            This is indented code in an indented block
+    :::
+    
+    ::: {.background-yellow}
+    This is not indented
+    :::
+
+this is not indented enough
+:::`, "§", "`")
+	src := []byte(srcString)
+
+	markdown := goldmark.New(
+		goldmark.WithExtensions(
+			&fences.Extender{},
+		),
+	)
+
+	doc := markdown.Parser().Parse(text.NewReader(src))
+	markdown.Renderer().Render(os.Stdout, src, doc)
+
+	// Output:
+	// <h2>Hello</h2>
+	// <p>This is outside</p>
+	// <pre><code>this is unindented code
+	// </code></pre>
+	// <pre><code>this is indented code
+	// </code></pre>
+	// <div data-fenceid="XVlBzgbaiCMRAjWwhTHctcuA" id="big-div" class="add-border">
+	// <p>This is indented</p>
+	// <div data-fenceid="xhxKQFDaFpLSjFbcXoEFfRsW" class="background-green font-big">
+	// <h2>This is indented within indented</h2>
+	// <pre><code>this is unindented code in an indented block
+	// </code></pre>
+	// <pre><code>This is indented code in an indented block
+	// </code></pre>
+	// </div>
+	// <div data-fenceid="xPLDnJObCsNVlgTeMaPEZQle" class="background-yellow">
+	// <p>This is not indented</p>
+	// </div>
+	// <p>s is not indented enough</p>
+	// </div>
+}