Data commit

Task/Truth-table/Ruby/truth-table.rb

@@ -0,0 +1,26 @@
+loop do
+  print "\ninput a boolean expression (e.g. 'a & b'): "
+  expr = gets.strip.downcase
+  break if expr.empty?
+
+  vars = expr.scan(/\p{Alpha}+/)
+  if vars.empty?
+    puts "no variables detected in your boolean expression"
+    next
+  end
+
+  vars.each {|v| print "#{v}\t"}
+  puts "| #{expr}"
+
+  prefix = []
+  suffix = []
+  vars.each do |v|
+    prefix << "[false, true].each do |#{v}|"
+    suffix << "end"
+  end
+
+  body = vars.inject("puts ") {|str, v| str + "#{v}.to_s + '\t' + "}
+  body += '"| " + eval(expr).to_s'
+
+  eval (prefix + [body] + suffix).join("\n")
+end