4 files changed, 137 insertions, 86 deletions
diff --git a/lib/prism/desugar_compiler.rb b/lib/prism/desugar_compiler.rb
index de02445149..c51bdd2b1c 100644
--- a/lib/prism/desugar_compiler.rb
+++ b/lib/prism/desugar_compiler.rb
@@ -2,11 +2,13 @@
 
 module Prism
   class DesugarAndWriteNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -14,22 +16,30 @@ module Prism
 
     # Desugar `x &&= y` to `x && x = y`
     def compile
-      AndNode.new(
-        source,
-        read_class.new(source, *arguments, node.name_loc),
-        write_class.new(source, *arguments, node.name_loc, node.value, node.operator_loc, node.location),
-        node.operator_loc,
-        node.location
+      and_node(
+        location: node.location,
+        left: public_send(read_class, location: node.name_loc, **arguments),
+        right: public_send(
+          write_class,
+          location: node.location,
+          **arguments,
+          name_loc: node.name_loc,
+          value: node.value,
+          operator_loc: node.operator_loc
+        ),
+        operator_loc: node.operator_loc
       )
     end
   end
 
   class DesugarOrWriteDefinedNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
+
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -37,35 +47,50 @@ module Prism
 
     # Desugar `x ||= y` to `defined?(x) ? x : x = y`
     def compile
-      IfNode.new(
-        source,
-        node.operator_loc,
-        DefinedNode.new(source, nil, read_class.new(source, *arguments, node.name_loc), nil, node.operator_loc, node.name_loc),
-        node.operator_loc,
-        StatementsNode.new(source, [read_class.new(source, *arguments, node.name_loc)], node.location),
-        ElseNode.new(
-          source,
-          node.operator_loc,
-          StatementsNode.new(
-            source,
-            [write_class.new(source, *arguments, node.name_loc, node.value, node.operator_loc, node.location)],
-            node.location
+      if_node(
+        location: node.location,
+        if_keyword_loc: node.operator_loc,
+        predicate: defined_node(
+          location: node.name_loc,
+          value: public_send(read_class, location: node.name_loc, **arguments),
+          keyword_loc: node.operator_loc
+        ),
+        then_keyword_loc: node.operator_loc,
+        statements: statements_node(
+          location: node.location,
+          body: [public_send(read_class, location: node.name_loc, **arguments)]
+        ),
+        consequent: else_node(
+          location: node.location,
+          else_keyword_loc: node.operator_loc,
+          statements: statements_node(
+            location: node.location,
+            body: [
+              public_send(
+                write_class,
+                location: node.location,
+                **arguments,
+                name_loc: node.name_loc,
+                value: node.value,
+                operator_loc: node.operator_loc
+              )
+            ]
           ),
-          node.operator_loc,
-          node.location
+          end_keyword_loc: node.operator_loc
         ),
-        node.operator_loc,
-        node.location
+        end_keyword_loc: node.operator_loc
       )
     end
   end
 
   class DesugarOperatorWriteNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -75,35 +100,41 @@ module Prism
     def compile
       binary_operator_loc = node.binary_operator_loc.chop
 
-      write_class.new(
-        source,
-        *arguments,
-        node.name_loc,
-        CallNode.new(
-          source,
-          0,
-          read_class.new(source, *arguments, node.name_loc),
-          nil,
-          binary_operator_loc.slice.to_sym,
-          binary_operator_loc,
-          nil,
-          ArgumentsNode.new(source, 0, [node.value], node.value.location),
-          nil,
-          nil,
-          node.location
+      public_send(
+        write_class,
+        location: node.location,
+        **arguments,
+        name_loc: node.name_loc,
+        value: call_node(
+          location: node.location,
+          receiver: public_send(
+            read_class,
+            location: node.name_loc,
+            **arguments
+          ),
+          name: binary_operator_loc.slice.to_sym,
+          message_loc: binary_operator_loc,
+          arguments: arguments_node(
+            location: node.value.location,
+            arguments: [node.value]
+          )
         ),
-        node.binary_operator_loc.copy(start_offset: node.binary_operator_loc.end_offset - 1, length: 1),
-        node.location
+        operator_loc: node.binary_operator_loc.copy(
+          start_offset: node.binary_operator_loc.end_offset - 1,
+          length: 1
+        )
       )
     end
   end
 
   class DesugarOrWriteNode # :nodoc:
-    attr_reader :node, :source, :read_class, :write_class, :arguments
+    include DSL
 
-    def initialize(node, source, read_class, write_class, *arguments)
+    attr_reader :node, :default_source, :read_class, :write_class, :arguments
+
+    def initialize(node, default_source, read_class, write_class, **arguments)
       @node = node
-      @source = source
+      @default_source = default_source
       @read_class = read_class
       @write_class = write_class
       @arguments = arguments
@@ -111,12 +142,18 @@ module Prism
 
     # Desugar `x ||= y` to `x || x = y`
     def compile
-      OrNode.new(
-        source,
-        read_class.new(source, *arguments, node.name_loc),
-        write_class.new(source, *arguments, node.name_loc, node.value, node.operator_loc, node.location),
-        node.operator_loc,
-        node.location
+      or_node(
+        location: node.location,
+        left: public_send(read_class, location: node.name_loc, **arguments),
+        right: public_send(
+          write_class,
+          location: node.location,
+          **arguments,
+          name_loc: node.name_loc,
+          value: node.value,
+          operator_loc: node.operator_loc
+        ),
+        operator_loc: node.operator_loc
       )
     end
   end
@@ -125,91 +162,91 @@ module Prism
 
   class ClassVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, ClassVariableReadNode, ClassVariableWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :class_variable_read_node, :class_variable_write_node, name: name).compile
     end
   end
 
   class ClassVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteDefinedNode.new(self, source, ClassVariableReadNode, ClassVariableWriteNode, name).compile
+      DesugarOrWriteDefinedNode.new(self, source, :class_variable_read_node, :class_variable_write_node, name: name).compile
     end
   end
 
   class ClassVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, ClassVariableReadNode, ClassVariableWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :class_variable_read_node, :class_variable_write_node, name: name).compile
     end
   end
 
   class ConstantAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, ConstantReadNode, ConstantWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :constant_read_node, :constant_write_node, name: name).compile
     end
   end
 
   class ConstantOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteDefinedNode.new(self, source, ConstantReadNode, ConstantWriteNode, name).compile
+      DesugarOrWriteDefinedNode.new(self, source, :constant_read_node, :constant_write_node, name: name).compile
     end
   end
 
   class ConstantOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, ConstantReadNode, ConstantWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :constant_read_node, :constant_write_node, name: name).compile
     end
   end
 
   class GlobalVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, GlobalVariableReadNode, GlobalVariableWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :global_variable_read_node, :global_variable_write_node, name: name).compile
     end
   end
 
   class GlobalVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteDefinedNode.new(self, source, GlobalVariableReadNode, GlobalVariableWriteNode, name).compile
+      DesugarOrWriteDefinedNode.new(self, source, :global_variable_read_node, :global_variable_write_node, name: name).compile
     end
   end
 
   class GlobalVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, GlobalVariableReadNode, GlobalVariableWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :global_variable_read_node, :global_variable_write_node, name: name).compile
     end
   end
 
   class InstanceVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, InstanceVariableReadNode, InstanceVariableWriteNode, name).compile
+      DesugarAndWriteNode.new(self, source, :instance_variable_read_node, :instance_variable_write_node, name: name).compile
     end
   end
 
   class InstanceVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteNode.new(self, source, InstanceVariableReadNode, InstanceVariableWriteNode, name).compile
+      DesugarOrWriteNode.new(self, source, :instance_variable_read_node, :instance_variable_write_node, name: name).compile
     end
   end
 
   class InstanceVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, InstanceVariableReadNode, InstanceVariableWriteNode, name).compile
+      DesugarOperatorWriteNode.new(self, source, :instance_variable_read_node, :instance_variable_write_node, name: name).compile
     end
   end
 
   class LocalVariableAndWriteNode
     def desugar # :nodoc:
-      DesugarAndWriteNode.new(self, source, LocalVariableReadNode, LocalVariableWriteNode, name, depth).compile
+      DesugarAndWriteNode.new(self, source, :local_variable_read_node, :local_variable_write_node, name: name, depth: depth).compile
     end
   end
 
   class LocalVariableOrWriteNode
     def desugar # :nodoc:
-      DesugarOrWriteNode.new(self, source, LocalVariableReadNode, LocalVariableWriteNode, name, depth).compile
+      DesugarOrWriteNode.new(self, source, :local_variable_read_node, :local_variable_write_node, name: name, depth: depth).compile
     end
   end
 
   class LocalVariableOperatorWriteNode
     def desugar # :nodoc:
-      DesugarOperatorWriteNode.new(self, source, LocalVariableReadNode, LocalVariableWriteNode, name, depth).compile
+      DesugarOperatorWriteNode.new(self, source, :local_variable_read_node, :local_variable_write_node, name: name, depth: depth).compile
     end
   end
 
diff --git a/lib/prism/node_ext.rb b/lib/prism/node_ext.rb
index aa6a18cf29..fe36be8541 100644
--- a/lib/prism/node_ext.rb
+++ b/lib/prism/node_ext.rb
@@ -69,11 +69,11 @@ module Prism
     def to_interpolated
       InterpolatedStringNode.new(
         source,
+        location,
         frozen? ? InterpolatedStringNodeFlags::FROZEN : 0,
         opening_loc,
-        [copy(opening_loc: nil, closing_loc: nil, location: content_loc)],
-        closing_loc,
-        location
+        [copy(location: content_loc, opening_loc: nil, closing_loc: nil)],
+        closing_loc
       )
     end
   end
@@ -86,10 +86,10 @@ module Prism
     def to_interpolated
       InterpolatedXStringNode.new(
         source,
+        location,
         opening_loc,
-        [StringNode.new(source, 0, nil, content_loc, nil, unescaped, content_loc)],
-        closing_loc,
-        location
+        [StringNode.new(source, content_loc, 0, nil, content_loc, nil, unescaped)],
+        closing_loc
       )
     end
   end
@@ -115,9 +115,9 @@ module Prism
       deprecated("value", "numerator", "denominator")
 
       if denominator == 1
-        IntegerNode.new(source, flags, numerator, location.chop)
+        IntegerNode.new(source, location.chop, flags, numerator)
       else
-        FloatNode.new(source, numerator.to_f / denominator, location.chop)
+        FloatNode.new(source, location.chop, numerator.to_f / denominator)
       end
     end
   end
@@ -195,7 +195,7 @@ module Prism
     # continue to supply that API.
     def child
       deprecated("name", "name_loc")
-      name ? ConstantReadNode.new(source, name, name_loc) : MissingNode.new(source, location)
+      name ? ConstantReadNode.new(source, name_loc, name) : MissingNode.new(source, location)
     end
   end
 
@@ -231,7 +231,7 @@ module Prism
     # continue to supply that API.
     def child
       deprecated("name", "name_loc")
-      name ? ConstantReadNode.new(source, name, name_loc) : MissingNode.new(source, location)
+      name ? ConstantReadNode.new(source, name_loc, name) : MissingNode.new(source, location)
     end
   end
 
diff --git a/lib/prism/parse_result.rb b/lib/prism/parse_result.rb
index cc4f942283..ae57242707 100644
--- a/lib/prism/parse_result.rb
+++ b/lib/prism/parse_result.rb
@@ -10,7 +10,11 @@ module Prism
     # specialized and more performant `ASCIISource` if no multibyte characters
     # are present in the source code.
     def self.for(source, start_line = 1, offsets = [])
-      source.ascii_only? ? ASCIISource.new(source, start_line, offsets): new(source, start_line, offsets)
+      if source.ascii_only?
+        ASCIISource.new(source, start_line, offsets)
+      else
+        new(source, start_line, offsets)
+      end
     end
 
     # The source code that this source object represents.
@@ -87,7 +91,12 @@ module Prism
     # encodings, it is not captured here.
     def code_units_offset(byte_offset, encoding)
       byteslice = (source.byteslice(0, byte_offset) or raise).encode(encoding)
-      (encoding == Encoding::UTF_16LE || encoding == Encoding::UTF_16BE) ? (byteslice.bytesize / 2) : byteslice.length
+
+      if encoding == Encoding::UTF_16LE || encoding == Encoding::UTF_16BE
+        byteslice.bytesize / 2
+      else
+        byteslice.length
+      end
     end
 
     # Returns the column number in code units for the given encoding for the
diff --git a/lib/prism/parse_result/errors.rb b/lib/prism/parse_result/errors.rb
index 40dda3c264..1eaeebee6e 100644
--- a/lib/prism/parse_result/errors.rb
+++ b/lib/prism/parse_result/errors.rb
@@ -4,13 +4,18 @@ require "stringio"
 
 module Prism
   class ParseResult < Result
+    # An object to represent the set of errors on a parse result. This object
+    # can be used to format the errors in a human-readable way.
     class Errors
+      # The parse result that contains the errors.
       attr_reader :parse_result
 
+      # Initialize a new set of errors from the given parse result.
       def initialize(parse_result)
         @parse_result = parse_result
       end
 
+      # Formats the errors in a human-readable way and return them as a string.
       def format
         error_lines = {}
         parse_result.errors.each do |error|