Add to_javascript denotational semantics

the_meaning_of_programs/denotational/add.rb

@@ -4,4 +4,8 @@ class Add
   def to_ruby
     "-> e { (#{left.to_ruby}).call(e) + (#{right.to_ruby}).call(e) }"
   end
+
+  def to_javascript
+    "function (e) { return (#{left.to_javascript}(e)) + (#{right.to_javascript}(e)); }"
+  end
 end

the_meaning_of_programs/denotational/assign.rb

@@ -1,7 +1,12 @@
+require 'execjs/json'
 require_relative '../syntax/assign'
 
 class Assign
   def to_ruby
     "-> e { e.merge({ #{name.inspect} => (#{expression.to_ruby}).call(e) }) }"
   end
+
+  def to_javascript
+    "function (e) { e[#{ExecJS::JSON.encode(name)}] = (#{expression.to_javascript}(e)); return e; }"
+  end
 end

the_meaning_of_programs/denotational/boolean.rb

@@ -1,7 +1,12 @@
+require 'execjs/json'
 require_relative '../syntax/boolean'
 
 class Boolean
   def to_ruby
     "-> e { #{value.inspect} }"
   end
+
+  def to_javascript
+    "function (e) { return #{ExecJS::JSON.encode(value)}; }"
+  end
 end

the_meaning_of_programs/denotational/do_nothing.rb

@@ -4,4 +4,8 @@ class DoNothing
   def to_ruby
     '-> e { e }'
   end
+
+  def to_javascript
+    'function (e) { return e; }'
+  end
 end

the_meaning_of_programs/denotational/if.rb

@@ -7,4 +7,11 @@ def to_ruby
       " else (#{alternative.to_ruby}).call(e)" +
       " end }"
   end
+
+  def to_javascript
+    "function (e) { if (#{condition.to_javascript}(e))" +
+      " { return (#{consequence.to_javascript}(e)); }" +
+      " else { return (#{alternative.to_javascript}(e)); }" +
+      " }"
+  end
 end

the_meaning_of_programs/denotational/less_than.rb

@@ -4,4 +4,8 @@ class LessThan
   def to_ruby
     "-> e { (#{left.to_ruby}).call(e) < (#{right.to_ruby}).call(e) }"
   end
+
+  def to_javascript
+    "function (e) { return (#{left.to_javascript}(e)) < (#{right.to_javascript}(e)); }"
+  end
 end

the_meaning_of_programs/denotational/multiply.rb

@@ -4,4 +4,8 @@ class Multiply
   def to_ruby
     "-> e { (#{left.to_ruby}).call(e) * (#{right.to_ruby}).call(e) }"
   end
+
+  def to_javascript
+    "function (e) { return (#{left.to_javascript}(e)) * (#{right.to_javascript}(e)); }"
+  end
 end

the_meaning_of_programs/denotational/number.rb

@@ -1,7 +1,12 @@
+require 'execjs/json'
 require_relative '../syntax/number'
 
 class Number
   def to_ruby
     "-> e { #{value.inspect} }"
   end
+
+  def to_javascript
+    "function (e) { return #{ExecJS::JSON.encode(value)}; }"
+  end
 end

the_meaning_of_programs/denotational/sequence.rb

@@ -4,4 +4,8 @@ class Sequence
   def to_ruby
     "-> e { (#{second.to_ruby}).call((#{first.to_ruby}).call(e)) }"
   end
+
+  def to_javascript
+    "function (e) { return (#{second.to_javascript}(#{first.to_javascript}(e))); }"
+  end
 end

the_meaning_of_programs/denotational/variable.rb

@@ -1,7 +1,12 @@
+require 'execjs/json'
 require_relative '../syntax/variable'
 
 class Variable
   def to_ruby
     "-> e { e[#{name.inspect}] }"
   end
+
+  def to_javascript
+    "function (e) { return e[#{ExecJS::JSON.encode(name)}]; }"
+  end
 end

the_meaning_of_programs/denotational/while.rb

@@ -7,4 +7,11 @@ def to_ruby
       " e" +
       " }"
   end
+
+  def to_javascript
+    "function (e) {" +
+      " while (#{condition.to_javascript}(e)) { e = (#{body.to_javascript}(e)); }" +
+      " return e;" +
+      " }"
+  end
 end