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annotate 1-Ruby/logic.rb @ 44:6347bacb3be7

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Add more notes about the DSL while I think about it Note: Several things don't make sense
author IBBoard <dev@ibboard.co.uk>
date Mon, 18 Sep 2017 20:53:36 +0100
parents e5b84cc7bc29
children
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1 #! /usr/bin/env ruby
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2
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3 x = 4
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4
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5 # "if" block is "if… end" - no "then" required
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6 if x == 4
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7 puts "x equals 4"
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8 end
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9
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10 # Python- and Perl-like following logic also works
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11 puts "x equals 4" if x == 4
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12 puts "x equals 4" unless x != 4
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13
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14 # Negation has many forms.
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15 # Simple logic:
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16 if x != 5
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17 puts "x not equal 5"
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18 end
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19
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20 # Two options on negation
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21 if !(x == 5)
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22 puts "x not equal 5"
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23 end
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24
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25 if not x == 5
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26 puts "x not equal 5"
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27 end
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28
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29 # "unless" blocks instead of "if"
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30 unless x != 4
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31 puts "x equal 4"
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32 else
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33 puts "x not equals 4"
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34 end
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35
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36 # "then" is optional, except in single line statement
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37 if x == 4 then puts "x equal 4" end
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38 if x == 4 then
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39 puts "x equal 4"
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40 end
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41 if x == 4
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42 puts "x equal 4"
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43 end
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44 # The following line gives:
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45 # logic.rb:…: syntax error, unexpected tIDENTIFIER, expecting keyword_then or ';' or '\n'
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46 # if x == 4 puts "x equal 4" end
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47 #
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48 # if x == 4 puts "x equal 4" end