calculator: use Unicode strings instead of single chars for operators

[nit.git] / examples / calculator / src / calculator_logic.nit

diff --git a/examples/calculator/src/calculator_logic.nit b/examples/calculator/src/calculator_logic.nit
index 9666d14..249962c 100644 (file)
--- a/examples/calculator/src/calculator_logic.nit
+++ b/examples/calculator/src/calculator_logic.nit
@@ -1,7 +1,5 @@
 # This file is part of NIT ( http://www.nitlanguage.org ).
 #
-# Copyright 2013-2014 Alexis Laferrière <alexis.laf@xymus.net>
-#
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
@@ -17,75 +15,116 @@
 # Business logic of a calculator
 module calculator_logic
 
+import serialization
+
+# Hold the state of the calculator and its services
 class CalculatorContext
-       var result : nullable Float = null
+       auto_serializable
+
+       # Result of the last operation
+       var result: nullable Numeric = null
+
+       # Last operation pushed with `push_op`, to be executed on the next push
+       var last_op: nullable Text = null
+
+       # Value currently being entered
+       var current: nullable FlatBuffer = null
+
+       # Text to display on screen
+       fun display_text: String
+       do
+               var result = result
+               var last_op = last_op
+               var current = current
 
-       var last_op : nullable Char = null
+               var buf = new FlatBuffer
 
-       var current : nullable Float = null
-       var after_point : nullable Int = null
+               if result != null and (current == null or last_op != "=") then
+                       if last_op == "=" then buf.append "= "
+
+                       buf.append result.to_s
+                       buf.add ' '
+               end
+
+               if last_op != null and last_op != "=" then
+                       buf.append last_op
+                       buf.add ' '
+               end
+
+               if current != null then
+                       buf.append current.to_s
+                       buf.add ' '
+               end
+
+               return buf.to_s
+       end
 
-       fun push_op( op : Char )
+       # Push operation `op`, will usually execute the last operation
+       fun push_op(op: Text)
        do
                apply_last_op_if_any
-               if op == 'C' then
-                       self.result = 0.0
+               if op == "C" then
+                       self.result = null
                        last_op = null
                else
                        last_op = op # store for next push_op
                end
 
                # prepare next current
-               after_point = null
-               current = null
+               self.current = null
        end
 
-       fun push_digit( digit : Int )
+       # Push a digit
+       fun push_digit(digit: Int)
        do
                var current = current
-               if current == null then current = 0.0
+               if current == null then current = new FlatBuffer
+               current.add digit.to_s.chars.first
+               self.current = current
 
-               var after_point = after_point
-               if after_point == null then
-                       current = current * 10.0 + digit.to_f
-               else
-                       current = current + digit.to_f * 10.0.pow(after_point.to_f)
-                       self.after_point -= 1
+               if last_op == "=" then
+                       self.result = null
+                       last_op = null
                end
-
-               self.current = current
        end
 
+       # Switch entry mode from integer to decimal
        fun switch_to_decimals
        do
-               if self.current == null then current = 0.0
-               if after_point != null then return
-
-               after_point = -1
+               var current = current
+               if current == null then current = new FlatBuffer.from("0")
+               if not current.chars.has('.') then current.add '.'
+               self.current = current
        end
 
-       fun apply_last_op_if_any
+       # Execute the last operation it not null
+       protected fun apply_last_op_if_any
        do
                var op = last_op
-
                var result = result
-               if result == null then result = 0.0
-
                var current = current
-               if current == null then current = 0.0
+               self.current = null
+
+               if current == null then return
 
                if op == null then
-                       result = current
-               else if op == '+' then
-                       result = result + current
-               else if op == '-' then
-                       result = result - current
-               else if op == '/' then
-                       result = result / current
-               else if op == '*' then
-                       result = result * current
+                       result = current.to_n
+               else if result != null then
+                       if op == "+" then
+                               result = result.add(current.to_n)
+                       else if op == "-" then
+                               result = result.sub(current.to_n)
+                       else if op == "/" or op == "÷" then
+                               result = result.div(current.to_n)
+                       else if op == "*" or op == "×" then
+                               result = result.mul(current.to_n)
+                       end
                end
+
                self.result = result
-               self.current = null
        end
 end
+
+redef universal Float
+       redef fun to_s do return to_precision(6)
+end