Added some helper methods

lib/exalted_math/ast.rb

@@ -129,6 +129,87 @@ def self.simplify(ast)
       end
     end
 
+    # Create a new num node
+    #
+    # @param value [Integer] The value of the new node
+    #
+    # @return [Ast] A num Ast Node
+    def self.num(value)
+      new('num', value)
+    end
+
+    # Create a new stat node
+    #
+    # @param value [String] The value of the new node
+    #
+    # @return [Ast] A stat Ast Node
+    def self.stat(value)
+      new('stat', value)
+    end
+
+    # Create a new spec node
+    #
+    # @param value [String] The value of the new node
+    #
+    # @return [Ast] A spec Ast Node
+    def self.spec(value)
+      new('spec', value)
+    end
+
+    # Create a new add node
+    #
+    # @param left [Ast] The left node of the add
+    # @param right [Ast] The right node of the add
+    # @return [Ast] An add Ast Node
+    def self.add(left, right)
+      new('add', left, right)
+    end
+
+    # Create a new sub node
+    #
+    # @param left [Ast] The left node of the sub
+    # @param right [Ast] The right node of the sub
+    # @return [Ast] An sub Ast Node
+    def self.sub(left, right)
+      new('sub', left, right)
+    end
+
+    # Create a new mul node
+    #
+    # @param left [Ast] The left node of the mul
+    # @param right [Ast] The right node of the mul
+    # @return [Ast] An mul Ast Node
+    def self.mul(left, right)
+      new('mul', left, right)
+    end
+
+    # Create a new div node
+    #
+    # @param left [Ast] The left node of the div
+    # @param right [Ast] The right node of the div
+    # @return [Ast] An div Ast Node
+    def self.div(left, right)
+      new('div', left, right)
+    end
+
+    # Create a new min node
+    #
+    # @param count [Integer] Number of values to sum for the min
+    # @param list  [Array]  Array of ASTs to calculate the min from
+    # @return [Ast] A min Ast Node
+    def self.min(count, list)
+      new('min', count, list)
+    end
+
+    # Create a new max node
+    #
+    # @param count [Integer] Number of values to sum for the max
+    # @param list  [Array]  Array of ASTs to calculate the max from
+    # @return [Ast] A max Ast Node
+    def self.max(count, list)
+      new('max', count, list)
+    end
+
     def self.from_array(array)
       case array[0]
       when 'mul', 'div', 'add', 'sub'

spec/ast_spec.rb

@@ -3,12 +3,15 @@
 require 'spec_helper'
 require 'exalted_math/ast'
 
+include Exalted
+
+
 describe "Exalted::Ast" do
   before do
     @three    = Exalted::Ast.new('num', 3 )
     @seven    = Exalted::Ast.new('num', 7 )
     @foo      = Exalted::Ast.new('stat', 'foo')
-    @bar      = Exalted::Ast.new('stat', 'bar')
+    @bar      = Exalted::Ast.new('spec', 'bar')
     @invalid  = Exalted::Ast.new('stat', 'invalid')
     @add      = Exalted::Ast.new('add', @three, @seven)
     @sub      = Exalted::Ast.new('sub', @three, @seven)
@@ -22,6 +25,34 @@
     @context  = { 'foo' => 3, 'bar' => 4 }
   end
 
+  it ".num makes a number" do
+    @three.should == Ast.num(3)
+  end
+
+  it ".stat makes a stat" do
+    @foo.should == Ast.stat('foo')
+  end
+
+  it ".spec makes a spec" do
+    @bar.should == Ast.spec('bar')
+  end
+
+  it ".add makes an add" do
+    @add.should == Ast.add(@three, @seven)
+  end
+
+  it ".sub makes an sub" do
+    @sub.should == Ast.sub(@three, @seven)
+  end
+
+  it ".mul makes an mul" do
+    @mul.should == Ast.mul(@three, @seven)
+  end
+
+  it ".div makes an div" do
+    @div.should == Ast.div(@seven, @three)
+  end
+
   it "a number is constant" do
     @three.should.be.constant
   end