Add Node#fence for code block metadata

context/getting-started.md

@@ -100,6 +100,18 @@ blocks and front matter. `Node#code_language` returns the first token of that
 info string, while `Node#fence_info` remains available for compatibility on
 those block nodes.
 
+For a fenced code block, `Node#fence` returns a `Node::Fence` structure with
+the fence character, length, and indentation:
+
+``` ruby
+block = Markly.parse("  ~~~~ ruby\n  Object.new\n  ~~~~").first_child
+
+block.fence
+# => #<struct Markly::Node::Fence character="~", length=4, indent=2>
+```
+
+Indented code blocks and other node types return `nil`.
+
 ## Extensions
 
 Both `render_html` and `parse` take an optional `extensions:` argument defining the extensions you want enabled as your CommonMark document is being processed:

ext/markly/markly.c

@@ -11,6 +11,7 @@
 static VALUE rb_Markly;
 static VALUE rb_Markly_Error;
 static VALUE rb_Markly_Node;
+static VALUE rb_Markly_Node_Fence;
 static VALUE rb_Markly_Parser;
 
 static VALUE sym_document;
@@ -1080,6 +1081,30 @@ static VALUE rb_node_set_code_info(VALUE self, VALUE info) {
 	return Qnil;
 }
 
+/*
+ * Public: Gets fencing details for the current node.
+ *
+ * Returns a {Markly::Node::Fence} for fenced code blocks, `nil` otherwise.
+ */
+static VALUE rb_node_get_fence(VALUE self) {
+	int fence_length = 0;
+	int fence_offset = 0;
+	char fence_character = '\0';
+	cmark_node *node;
+	TypedData_Get_Struct(self, cmark_node, &rb_Markly_Node_Type, node);
+
+	if (!cmark_node_get_fenced(node, &fence_length, &fence_offset, &fence_character)) {
+		return Qnil;
+	}
+
+	return rb_struct_new(
+		rb_Markly_Node_Fence,
+		rb_str_new(&fence_character, 1),
+		INT2NUM(fence_length),
+		INT2NUM(fence_offset)
+	);
+}
+
 static VALUE rb_node_get_tasklist_item_checked(VALUE self) {
 	int tasklist_state;
 	cmark_node *node;
@@ -1260,6 +1285,7 @@ __attribute__((visibility("default"))) void Init_markly(void) {
 	rb_Markly_Node = rb_define_class_under(rb_Markly, "Node", rb_cObject);
 	rb_undef_alloc_func(rb_Markly_Node);
 	rb_define_singleton_method(rb_Markly_Node, "new", rb_node_new, 1);
+	rb_Markly_Node_Fence = rb_struct_define_under(rb_Markly_Node, "Fence", "character", "length", "indent", NULL);
 
 	rb_define_method(rb_Markly_Node, "replace", rb_node_replace, 1);
 
@@ -1297,6 +1323,7 @@ __attribute__((visibility("default"))) void Init_markly(void) {
 	rb_define_method(rb_Markly_Node, "fence_info=", rb_node_set_fence_info, 1);
 	rb_define_method(rb_Markly_Node, "code_info", rb_node_get_code_info, 0);
 	rb_define_method(rb_Markly_Node, "code_info=", rb_node_set_code_info, 1);
+	rb_define_method(rb_Markly_Node, "fence", rb_node_get_fence, 0);
 	rb_define_method(rb_Markly_Node, "table_alignments", rb_node_get_table_alignments, 0);
 	rb_define_method(rb_Markly_Node, "tasklist_item_checked?", rb_node_get_tasklist_item_checked, 0);
 	rb_define_method(rb_Markly_Node, "tasklist_item_checked=", rb_node_set_tasklist_item_checked, 1);

guides/getting-started/readme.md

@@ -100,6 +100,18 @@ blocks and front matter. `Node#code_language` returns the first token of that
 info string, while `Node#fence_info` remains available for compatibility on
 those block nodes.
 
+For a fenced code block, `Node#fence` returns a `Node::Fence` structure with
+the fence character, length, and indentation:
+
+``` ruby
+block = Markly.parse("  ~~~~ ruby\n  Object.new\n  ~~~~").first_child
+
+block.fence
+# => #<struct Markly::Node::Fence character="~", length=4, indent=2>
+```
+
+Indented code blocks and other node types return `nil`.
+
 ## Extensions
 
 Both `render_html` and `parse` take an optional `extensions:` argument defining the extensions you want enabled as your CommonMark document is being processed:

releases.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
   - Add opt-in language prefixes for inline code spans with `Markly::INLINE_CODE_INFO`, expose code metadata through `Node#code_info`, and provide `Node#code_language` as a convenient language accessor.
+  - Expose fenced code-block metadata through `Node#fence` and `Node::Fence`.
 
 ## v0.16.0
 

test/markly/node.rb

@@ -225,6 +225,34 @@
 		end
 	end
 
+	with "#fence" do
+		let(:fenced_backtick_node) {Markly.parse("``` ruby\nputs 'wow'\n```").first_child}
+		let(:fenced_tilde_node) {Markly.parse("  ~~~~ ruby\n  puts 'wow'\n  ~~~~").first_child}
+		let(:indented_code_node) {Markly.parse("    puts 'wow'").first_child}
+		let(:paragraph_node) {Markly.parse("hello").first_child}
+
+		it "returns fenced metadata for backtick fences" do
+			expect(fenced_backtick_node.fence).to be == Markly::Node::Fence.new("`", 3, 0)
+		end
+
+		it "returns fenced metadata for tilde fences" do
+			fence = fenced_tilde_node.fence
+
+			expect(fence).to be_a(Markly::Node::Fence)
+			expect(fence.character).to be == "~"
+			expect(fence.length).to be == 4
+			expect(fence.indent).to be == 2
+		end
+
+		it "returns nil for non-fenced code blocks" do
+			expect(indented_code_node.fence).to be_nil
+		end
+
+		it "returns nil for non-code nodes" do
+			expect(paragraph_node.fence).to be_nil
+		end
+	end
+
 	with "#find_header" do
 		let(:document) {Markly.parse("# Heading\n\n## Subheading")}