removed the structs (code smell)

lib/crystal.rb

@@ -6,4 +6,6 @@ require "asm/stack_instruction"
 require "asm/arm_assembler"
 require "elf/object_writer"
 require 'vm/parser'
+require 'vm/nodes'
+require 'vm/transform'
 

lib/vm/compiler.rb

@@ -54,7 +54,7 @@ module Vm
     end
 
     def split_functions(tree)
-      first_expr = tree.index { |t| ! t.is_a?(Function) }
+      first_expr = tree.index { |t| ! t.is_a?(FunctionExpression) }
       funcs = first_expr ? tree[0...first_expr] : tree
       exprs = first_expr ? tree[first_expr..-1] : []
 

lib/vm/nodes.rb

@@ -1,11 +1,27 @@
 module Vm
-  class Number < Struct.new :value
+  
+  class Expression
+    # evey Expression has a eval function that returns a value
+    def eval 
+      raise "abstract"
+    end
+  end
+
+  class NumberExpression < Expression
+    attr_reader :value
+    def initialize val
+      @value = val
+    end
     def eval(context, builder)
       builder.mov "r0" , value
     end
   end
 
-  class Name < Struct.new :name
+  class NameExpression < Expression
+    attr_reader  :name
+    def initialize name
+      @name = name
+    end
     def eval(context, builder)
       param_names = context[:params] || []
       position    = param_names.index(name)
@@ -15,7 +31,11 @@ module Vm
     end
   end
 
-  class Funcall < Struct.new :name, :args
+  class FuncallExpression < Expression
+    attr_reader  :name, :args
+    def initialize name, args
+      @name , @args = name , args
+    end
     def eval(context, builder)
       args.each { |a| a.eval(context, builder) }
       types = [builder.int] * (args.length + 1)
@@ -23,7 +43,11 @@ module Vm
     end
   end
 
-  class Conditional < Struct.new :cond, :if_true, :if_false
+  class ConditionalExpression < Expression
+    attr_reader  :cond, :if_true, :if_false
+    def initialize cond, if_true, if_false
+      @cond, @if_true, @if_false = cond, if_true, if_false
+    end
     def eval(context, builder)
       cond.eval context, builder
 
@@ -39,7 +63,11 @@ module Vm
     end
   end
 
-  class Function < Struct.new :name, :params, :body
+  class FunctionExpression < Expression
+    attr_reader  :name, :params, :body
+    def initialize name, params, body
+      @name, @params, @body = name, params, body
+    end
     def eval(context, builder)
       param_names = [params].flatten.map(&:name)
       context[:params] = param_names

lib/vm/transform.rb

@@ -3,31 +3,31 @@ require 'vm/nodes'
 
 module Vm
   class Transform < Parslet::Transform
-    rule(:number => simple(:value)) { Number.new(value.to_i) }
-    rule(:name   => simple(:name))  { Name.new(name.to_s) }
+    rule(:number => simple(:value)) { NumberExpression.new(value.to_i) }
+    rule(:name   => simple(:name))  { NameExpression.new(name.to_s) }
 
     rule(:arg  => simple(:arg))    { arg  }
     rule(:args => sequence(:args)) { args }
 
     rule(:funcall => simple(:funcall),
-         :args    => simple(:args))   { Funcall.new(funcall.name, [args]) }
+         :args    => simple(:args))   { FuncallExpression.new(funcall.name, [args]) }
 
     rule(:funcall => simple(:funcall),
-         :args    => sequence(:args)) { Funcall.new(funcall.name, args) }
+         :args    => sequence(:args)) { FuncallExpression.new(funcall.name, args) }
 
     rule(:cond     => simple(:cond),
          :if_true  => {:body => simple(:if_true)},
-         :if_false => {:body => simple(:if_false)}) { Conditional.new(cond, if_true, if_false) }
+         :if_false => {:body => simple(:if_false)}) { ConditionalExpression.new(cond, if_true, if_false) }
 
     rule(:param  => simple(:param))    { param  }
     rule(:params => sequence(:params)) { params }
 
     rule(:func   => simple(:func),
          :params => simple(:name),
-         :body   => simple(:body)) { Function.new(func.name, [name], body) }
+         :body   => simple(:body)) { FunctionExpression.new(func.name, [name], body) }
 
     rule(:func   => simple(:func),
          :params => sequence(:params),
-         :body   => simple(:body)) { Function.new(func.name, params, body) }
+         :body   => simple(:body)) { FunctionExpression.new(func.name, params, body) }
   end
 end