Add Node#fenced method for code block fence metadata

Returns a hash with {:info, :length, :character, :offset} for fenced code blocks, nil for non-fenced or non-code-block nodes.

Author: kristoph

ext/markly/markly.c

@@ -1028,6 +1028,36 @@ static VALUE rb_node_set_fence_info(VALUE self, VALUE info) {
 	return Qnil;
 }
 
+/*
+ * Public: Gets fencing details for the current node.
+ *
+ * Returns a {Hash} with `:info`, `:length`, `:character`, and `:offset` keys
+ * for fenced code blocks, `nil` otherwise.
+ */
+static VALUE rb_node_get_fenced(VALUE self) {
+	const char *fence_info;
+	int fence_length = 0;
+	int fence_offset = 0;
+	char fence_character = '\0';
+	cmark_node *node;
+	VALUE result;
+	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;
+	}
+	
+	fence_info = cmark_node_get_fence_info(node);
+	
+	result = rb_hash_new();
+	rb_hash_aset(result, CSTR2SYM("info"), fence_info ? rb_str_new2(fence_info) : rb_str_new("", 0));
+	rb_hash_aset(result, CSTR2SYM("length"), INT2NUM(fence_length));
+	rb_hash_aset(result, CSTR2SYM("character"), rb_str_new(&fence_character, 1));
+	rb_hash_aset(result, CSTR2SYM("offset"), INT2NUM(fence_offset));
+	
+	return result;
+}
+
 static VALUE rb_node_get_tasklist_item_checked(VALUE self) {
 	int tasklist_state;
 	cmark_node *node;
@@ -1242,6 +1272,7 @@ __attribute__((visibility("default"))) void Init_markly(void) {
 	rb_define_method(rb_Markly_Node, "list_tight=", rb_node_set_list_tight, 1);
 	rb_define_method(rb_Markly_Node, "fence_info", rb_node_get_fence_info, 0);
 	rb_define_method(rb_Markly_Node, "fence_info=", rb_node_set_fence_info, 1);
+	rb_define_method(rb_Markly_Node, "fenced", rb_node_get_fenced, 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);

test/markly/node.rb

@@ -215,6 +215,39 @@
 		end
 	end
 
+	with "#fenced" do
+		let(:fenced_backtick_node) {Markly.parse("``` ruby\nputs 'wow'\n```").first_child}
+		let(:fenced_tilde_node) {Markly.parse("~~~ ruby\nputs '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.fenced).to be == {
+				info: "ruby",
+				length: 3,
+				character: "`",
+				offset: 0
+			}
+		end
+		
+		it "returns fenced metadata for tilde fences" do
+			expect(fenced_tilde_node.fenced).to be == {
+				info: "ruby",
+				length: 3,
+				character: "~",
+				offset: 0
+			}
+		end
+		
+		it "returns nil for non-fenced code blocks" do
+			expect(indented_code_node.fenced).to be_nil
+		end
+		
+		it "returns nil for non-code nodes" do
+			expect(paragraph_node.fenced).to be_nil
+		end
+	end
+	
 	with "#find_header" do
 		let(:document) {Markly.parse("# Heading\n\n## Subheading")}