add constant

app/models/logic/constant.rb

@@ -0,0 +1,39 @@
+class Logic::Constant < Logic::Term
+  attr_reader :value
+
+  def initialize(value)
+    @value = value
+  end
+
+  def compute(_champs = nil) = @value
+
+  def to_s = @value.to_s
+
+  def type
+    case @value
+    when TrueClass, FalseClass
+      :boolean
+    when Integer, Float
+      :number
+    else
+      @value.class.name.downcase.to_sym
+    end
+  end
+
+  def errors(_stable_ids = nil) = []
+
+  def to_h
+    {
+      "op" => self.class.name,
+      "value" => @value
+    }
+  end
+
+  def self.from_h(h)
+    self.new(h['value'])
+  end
+
+  def ==(other)
+    self.class == other.class && @value == other.value
+  end
+end

app/models/logic/term.rb

@@ -0,0 +1,5 @@
+class Logic::Term
+  def to_json
+    to_h.to_json
+  end
+end