Initial commit

Author: kddnewton

.gitignore

@@ -0,0 +1 @@
+test.xml

Gemfile

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gem "prettier_print"
+gem "syntax_tree"

Gemfile.lock

@@ -0,0 +1,16 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    prettier_print (0.1.0)
+    syntax_tree (2.7.1)
+      prettier_print
+
+PLATFORMS
+  x86_64-darwin-21
+
+DEPENDENCIES
+  prettier_print
+  syntax_tree
+
+BUNDLED WITH
+   2.4.0.dev

lib/syntax_tree/xml.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require "prettier_print"
+require "syntax_tree"
+
+require_relative "xml/nodes"
+require_relative "xml/parser"
+require_relative "xml/visitor"
+
+require_relative "xml/format"
+require_relative "xml/pretty_print"
+
+module SyntaxTree
+  module XML
+    def self.format(source, maxwidth = 80)
+      PrettierPrint.format(+"", maxwidth) { |q| parse(source).format(q) }
+    end
+
+    def self.parse(source)
+      Parser.new(source).parse
+    end
+
+    def self.read(filepath)
+      File.read(filepath)
+    end
+  end
+
+  register_handler(".xml", XML)
+end

lib/syntax_tree/xml/format.rb

@@ -0,0 +1,241 @@
+# frozen_string_literal: true
+
+module SyntaxTree
+  module XML
+    class Format < Visitor
+      attr_reader :q
+
+      def initialize(q)
+        @q = q
+      end
+
+      # Visit a Token node.
+      def visit_token(node)
+        q.text(node.value.strip)
+      end
+
+      # Visit a Document node.
+      def visit_document(node)
+        child_nodes =
+          node
+            .child_nodes
+            .select do |child_node|
+              case child_node
+              in Misc[value: Token[type: :whitespace]]
+                false
+              else
+                true
+              end
+            end
+            .sort_by(&:location)
+
+        q.seplist(child_nodes, -> { q.breakable(force: true) }) do |child_node|
+          visit(child_node)
+        end
+
+        q.breakable(force: true)
+      end
+
+      # Visit a Prolog node.
+      def visit_prolog(node)
+        q.group do
+          visit(node.opening)
+
+          if node.attributes.any?
+            q.indent do
+              q.breakable("")
+              q.seplist(node.attributes, -> { q.breakable }) do |child_node|
+                visit(child_node)
+              end
+            end
+          end
+
+          q.breakable
+          visit(node.closing)
+        end
+      end
+
+      # Visit a Doctype node.
+      def visit_doctype(node)
+        q.group do
+          visit(node.opening)
+          q.text(" ")
+          visit(node.name)
+
+          if node.external_id
+            q.text(" ")
+            visit(node.external_id)
+          end
+
+          visit(node.closing)
+        end
+      end
+
+      # Visit an ExternalID node.
+      def visit_external_id(node)
+        q.group do
+          q.group do
+            visit(node.type)
+
+            if node.public_id
+              q.indent do
+                q.breakable
+                visit(node.public_id)
+              end
+            end
+          end
+
+          q.indent do
+            q.breakable
+            visit(node.system_id)
+          end
+        end
+      end
+
+      # Visit an Element node.
+      def visit_element(node)
+        inner_nodes =
+          node.content&.select do |child_node|
+            case child_node
+            in CharData[value: Token[type: :whitespace]]
+              false
+            in CharData[value: Token[value:]] if value.strip.empty?
+              false
+            else
+              true
+            end
+          end
+
+        case inner_nodes
+        in nil
+          visit(node.opening_tag)
+        in []
+          visit(
+            Element::OpeningTag.new(
+              opening: node.opening_tag.opening,
+              name: node.opening_tag.name,
+              attributes: node.opening_tag.attributes,
+              closing:
+                Token.new(
+                  type: :close,
+                  value: "/>",
+                  location: node.opening_tag.closing.location
+                ),
+              location: node.opening_tag.location
+            )
+          )
+        in [CharData[value: Token[type: :text, value:]]]
+          q.group do
+            visit(node.opening_tag)
+            q.indent do
+              q.breakable("")
+              format_text(q, value)
+            end
+
+            q.breakable("")
+            visit(node.closing_tag)
+          end
+        else
+          q.group do
+            visit(node.opening_tag)
+            q.indent do
+              q.breakable("")
+
+              inner_nodes.each_with_index do |child_node, index|
+                if index != 0
+                  q.breakable(force: true)
+
+                  end_line = inner_nodes[index - 1].location.end_line
+                  start_line = child_node.location.start_line
+                  q.breakable(force: true) if (start_line - end_line) >= 2
+                end
+
+                case child_node
+                in CharData[value: Token[type: :text, value:]]
+                  format_text(q, value)
+                else
+                  visit(child_node)
+                end
+              end
+            end
+
+            q.breakable(force: true)
+            visit(node.closing_tag)
+          end
+        end
+      end
+
+      # Visit an Element::OpeningTag node.
+      def visit_opening_tag(node)
+        q.group do
+          visit(node.opening)
+          visit(node.name)
+
+          if node.attributes.any?
+            q.indent do
+              q.breakable
+              q.seplist(node.attributes, -> { q.breakable }) do |child_node|
+                visit(child_node)
+              end
+            end
+          end
+
+          q.breakable(node.closing.value == "/>" ? " " : "")
+          visit(node.closing)
+        end
+      end
+
+      # Visit an Element::ClosingTag node.
+      def visit_closing_tag(node)
+        q.group do
+          visit(node.opening)
+          visit(node.name)
+          visit(node.closing)
+        end
+      end
+
+      # Visit a Reference node.
+      def visit_reference(node)
+        visit(node.value)
+      end
+
+      # Visit an Attribute node.
+      def visit_attribute(node)
+        q.group do
+          visit(node.key)
+          visit(node.equals)
+          visit(node.value)
+        end
+      end
+
+      # Visit a CharData node.
+      def visit_char_data(node)
+        lines = node.value.value.strip.split("\n")
+
+        q.seplist(lines, -> { q.breakable(indent: false) }) do |line|
+          q.text(line)
+        end
+      end
+
+      # Visit a Misc node.
+      def visit_misc(node)
+        visit(node.value)
+      end
+
+      private
+
+      # Format a text by splitting nicely at newlines and spaces.
+      def format_text(q, value)
+        q.seplist(
+          value.strip.split("\n"),
+          -> { q.breakable(force: true, indent: false) }
+        ) do |line|
+          q.seplist(
+            line.split(/\b(?: +)\b/),
+            -> { q.group { q.breakable } }
+          ) { |segment| q.text(segment) }
+        end
+      end
+    end
+  end
+end