|
8
|
1 logic.rb(main):001:0> #! /usr/bin/env ruby
|
|
|
2 logic.rb(main):002:0*
|
|
|
3 logic.rb(main):003:0* x = 4
|
|
|
4 => 4
|
|
|
5 logic.rb(main):004:0>
|
|
|
6 logic.rb(main):005:0* # "if" block is "if… end" - no "then" required
|
|
|
7 logic.rb(main):006:0* if x == 4
|
|
|
8 logic.rb(main):007:1> puts "x equals 4"
|
|
|
9 logic.rb(main):008:1> end
|
|
|
10 x equals 4
|
|
|
11 => nil
|
|
|
12 logic.rb(main):009:0>
|
|
|
13 logic.rb(main):010:0* # Python- and Perl-like following logic also works
|
|
|
14 logic.rb(main):011:0* puts "x equals 4" if x == 4
|
|
|
15 x equals 4
|
|
|
16 => nil
|
|
|
17 logic.rb(main):012:0> puts "x equals 4" unless x != 4
|
|
|
18 x equals 4
|
|
|
19 => nil
|
|
|
20 logic.rb(main):013:0>
|
|
|
21 logic.rb(main):014:0* # Negation has many forms.
|
|
|
22 logic.rb(main):015:0* # Simple logic:
|
|
|
23 logic.rb(main):016:0* if x != 5
|
|
|
24 logic.rb(main):017:1> puts "x not equal 5"
|
|
|
25 logic.rb(main):018:1> end
|
|
|
26 x not equal 5
|
|
|
27 => nil
|
|
|
28 logic.rb(main):019:0>
|
|
|
29 logic.rb(main):020:0* # Two options on negation
|
|
|
30 logic.rb(main):021:0* if !(x == 5)
|
|
|
31 logic.rb(main):022:1> puts "x not equal 5"
|
|
|
32 logic.rb(main):023:1> end
|
|
|
33 x not equal 5
|
|
|
34 => nil
|
|
|
35 logic.rb(main):024:0>
|
|
|
36 logic.rb(main):025:0* if not x == 5
|
|
|
37 logic.rb(main):026:1> puts "x not equal 5"
|
|
|
38 logic.rb(main):027:1> end
|
|
|
39 x not equal 5
|
|
|
40 => nil
|
|
|
41 logic.rb(main):028:0>
|
|
|
42 logic.rb(main):029:0* # "unless" blocks instead of "if"
|
|
|
43 logic.rb(main):030:0* unless x != 4
|
|
|
44 logic.rb(main):031:1> puts "x equal 4"
|
|
|
45 logic.rb(main):032:1> else
|
|
|
46 logic.rb(main):033:1* puts "x not equals 4"
|
|
|
47 logic.rb(main):034:1> endlogic.rb(main):034:1>
|
|
|
48 x equal 4
|
|
|
49 => nil
|
|
|
50 logic.rb(main):034:0>
|
