rhyhann · December 7, 2009 16:50 · Dec 7, 2009 · Dec 7, 2009 · Dec 7, 2009 · Dec 7, 2009
diff --git a/polynomial.rb b/polynomial.rb
@@ -7,6 +7,9 @@
 # specs. It's possible to have a beautiful output (2x³+3x²+10x-1)
 # and also several compression types: (x + 5) or (2x² -3x +5)
 
+# Also, shouldn't we do that: puts @polynomial.to_s
+# instead of that: puts @polynomial ?
+
 require 'enumerator'
 # Code
 class Integer

diff --git a/gistfile1.rb → polynomial.rb b/gistfile1.rb → polynomial.rb
@@ -3,6 +3,10 @@
 # The code passes the test but why is @p4 considered as a polynomial ?
 # An ArgumentError should be thrown.
 
+# Oh, and... it's got a lot of unseen features. Just see my personal
+# specs. It's possible to have a beautiful output (2x³+3x²+10x-1)
+# and also several compression types: (x + 5) or (2x² -3x +5)
+
 require 'enumerator'
 # Code
 class Integer

diff --git a/testsuite.txt b/testsuite.txt
@@ -0,0 +1,14 @@
+$ ruby test_polynomial.rb 
+Loaded suite Polynomial_Test
+Started
+.....
+Finished in 0.00074 seconds.
+
+5 tests, 6 assertions, 0 failures, 0 errors
+
+$ ruby polynomial.rb 
+.......
+
+Finished in 0.002794 seconds
+
+7 examples, 0 failures
diff --git a/gistfile1.rb b/gistfile1.rb
@@ -1,5 +1,8 @@
 #!/usr/bin/env ruby
 # Polynomial beautifier, by Othmane Benkirane
+# The code passes the test but why is @p4 considered as a polynomial ?
+# An ArgumentError should be thrown.
+
 require 'enumerator'
 # Code
 class Integer
@@ -11,9 +14,10 @@ class Polynomial
   attr_accessor :output
   attr_reader :compression
   def initialize(numbers)
+    raise ArgumentError, 'Need at least 2 coefficients' if numbers.size < 2
     numbers.shift while numbers.first == 0
     @numbers,@output = numbers,:ugly
-    self.compression = :none
+    self.compression = :full
   end
   def compression=(compression)
     @b_,@a_ = case compression
@@ -24,8 +28,9 @@ def compression=(compression)
     end
   end
   def to_s
-    numbers {|@num, @exp| [coef, exponent] unless coef.nil?}.
-    reject {|l| l.nil?}.flatten.join
+    @numbers.empty? ? '0' :
+      numbers {|@num, @exp| [coef, exponent] unless coef.nil?}.
+      reject {|l| l.nil?}.flatten.join
   end
   alias inspect to_s
 
@@ -78,6 +83,7 @@ def numbers
       @zero     = Polynomial.new([0,1,2,3,0,4,0])
       @x1       = Polynomial.new([3,4])
       @long     = Polynomial.new((0..20).map{|l| l%5==0 ? 1 : 0}.reverse)
+      [@no_one,@negative,@zero,@x1,@long].each {|p| p.compression = :none}
     end
     it 'should not show a coefficient equal to 1' do
       @no_one.to_s.should == 'x^2 + x + 1'

diff --git a/gistfile1.rb b/gistfile1.rb
@@ -24,17 +24,21 @@ def compression=(compression)
     end
   end
   def to_s
-    map {|@num, @exp| [coef, exponent] unless coef.nil?}.
+    numbers {|@num, @exp| [coef, exponent] unless coef.nil?}.
     reject {|l| l.nil?}.flatten.join
   end
   alias inspect to_s
 
   private
   def coef
     return nil if @num == 0
-    out_number = @num.abs unless (@num == 1 || @num == -1) && @exp != 0
     "#{sign}#{out_number}"
   end
+
+  def out_number
+    @num.abs unless (@num == 1 || @num == -1) && @exp != 0
+  end
+
   def sign
     if @exp == @numbers.size - 1
       "#{@num.sign}#@a_" if @num.sign == '-'
@@ -55,7 +59,8 @@ def exponent
     end
     "x#{output}"
   end
-  def map
+
+  def numbers
     @numbers.reverse.enum_with_index.map do |num, exp|
       yield num, exp
     end.reverse

diff --git a/gistfile1.rb b/gistfile1.rb
@@ -0,0 +1,103 @@
+#!/usr/bin/env ruby
+# Polynomial beautifier, by Othmane Benkirane
+require 'enumerator'
+# Code
+class Integer
+  def sign
+    self >= 0 ? '+' : '-'
+  end
+end
+class Polynomial
+  attr_accessor :output
+  attr_reader :compression
+  def initialize(numbers)
+    numbers.shift while numbers.first == 0
+    @numbers,@output = numbers,:ugly
+    self.compression = :none
+  end
+  def compression=(compression)
+    @b_,@a_ = case compression
+    when :none; [' ', ' ']
+    when :semi; [' ', '']
+    when :full; ['','']
+    else;       ['','']  
+    end
+  end
+  def to_s
+    map {|@num, @exp| [coef, exponent] unless coef.nil?}.
+    reject {|l| l.nil?}.flatten.join
+  end
+  alias inspect to_s
+
+  private
+  def coef
+    return nil if @num == 0
+    out_number = @num.abs unless (@num == 1 || @num == -1) && @exp != 0
+    "#{sign}#{out_number}"
+  end
+  def sign
+    if @exp == @numbers.size - 1
+      "#{@num.sign}#@a_" if @num.sign == '-'
+    else
+      "#@b_#{@num.sign}#@a_"
+    end
+  end
+
+  def exponent
+    exp = @exp.to_s
+    return 'x' if exp=='1'
+    return ''  if exp=='0'
+    output = case @output
+      when :ugly; "^#{exp}"
+      when :beautiful
+        @@exponents ||= %w(⁰ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹)
+        exp.split('').map {|n| @@exponents[n.to_i]}.join
+    end
+    "x#{output}"
+  end
+  def map
+    @numbers.reverse.enum_with_index.map do |num, exp|
+      yield num, exp
+    end.reverse
+  end
+end
+
+# Test suite
+if $0 == __FILE__
+  require 'rubygems'
+  require 'spec'
+  describe "Polynomial" do
+    before do
+      @no_one   = Polynomial.new([1,1,1])
+      @negative = Polynomial.new([-1,-2,-3])
+      @zero     = Polynomial.new([0,1,2,3,0,4,0])
+      @x1       = Polynomial.new([3,4])
+      @long     = Polynomial.new((0..20).map{|l| l%5==0 ? 1 : 0}.reverse)
+    end
+    it 'should not show a coefficient equal to 1' do
+      @no_one.to_s.should == 'x^2 + x + 1'
+    end
+    it 'should also support compacted output' do
+      @no_one.compression = :full
+      @no_one.to_s.should == 'x^2+x+1'
+    end
+    it 'should also support semi-compacted output' do
+      @no_one.compression = :semi
+      @no_one.to_s.should == 'x^2 +x +1'
+    end
+    it 'should not show + then -' do
+      @negative.to_s.should == '- x^2 - 2x - 3'
+    end
+    it 'should not output zero polynomials' do
+      @zero.to_s.should == 'x^5 + 2x^4 + 3x^3 + 4x'
+    end
+    it 'should not put ^1' do
+      @x1.to_s.should == '3x + 4'
+    end
+    it 'should also output beautiful polynomials' do
+      @long.output = :beautiful
+      @long.to_s.should == 'x²⁰ + x¹⁵ + x¹⁰ + x⁵ + 1'
+    end
+  end
+  Spec::Runner.run
+end