Added a partial implementation of the excel TEXT(number,format) function

lib/formulae/compile/formula_builder.rb

@@ -177,6 +177,7 @@ def self.excel_function(name,name_to_use_in_ruby = name)
     excel_function :pmt
     excel_function :npv
     excel_function :countif
+    excel_function :text
 
     def standard_function(name_to_use_in_ruby,args)
       "#{name_to_use_in_ruby}(#{args.map {|a| a.visit(self) }.join(',')})"

lib/formulae/run/excel_functions.rb

@@ -104,6 +104,13 @@ def find_or_create_worksheet(worksheet_name)
       worksheet
     end
 
+    def text(number,format)
+      return number if iserr(number)
+      return format if iserr(format)
+      raise Exception.new("format #{format} not implemented") unless format.is_a?(Numeric)
+      number.round(format).to_s
+    end
+
     def round(number,decimal_places)
       return number if iserr(number)
       return decimal_places if iserr(decimal_places)

spec/excel_functions_spec.rb

@@ -316,6 +316,14 @@ def a1; 10.0; end
   end
 end
 
+describe "text" do
+  it "should round a numeric value to a number of decimal places and then return a string if in the format text(3.1415,0), otherwise not implemented" do
+    FunctionTest.text(3.1415,0).should == "3"
+    FunctionTest.text(3.1415,1).should == "3.1"
+  end
+end
+
+
 describe "excel comparisons" do
 
   it "should carry out comparisons in the usual way" do