dbourguignon · July 9, 2021 01:16 · Dec 28, 2018 · Dec 28, 2018 · Dec 28, 2018 · Dec 28, 2018
diff --git a/proc_composition-2.rb b/proc_composition-2.rb
@@ -6,6 +6,7 @@
 PREMIUM       = ->(val) { val + 10 }
 DISCOUNT      = ->(val) { val * 0.90 }
 ROUND_TO_CENT = ->(val) { val.round(2) }
+# One presenter
 PRESENT       = ->(val) { val.to_f }
 
 # Pre-define some rule set for some pricing scenarios

diff --git a/proc_composition-2.rb b/proc_composition-2.rb
@@ -1,34 +1,24 @@
 require "bigdecimal"
 
 # List of our individual pricing rules
-PRICE_RULE_DEFINTIONS = {
-  tax: ->(val) { val + val*0.05 },
-  fee: ->(val) { val + 1 },
-  premium: ->(val) { val + 10 },
-  discount: ->(val) { val * 0.90 },
-  round_to_cent: ->(val) { val.round(2) }
-}
-
-# Some helper to pick a rule
-def rule(name)
-  PRICE_RULE_DEFINTIONS[name]
-end
+TAX           = ->(val) { val + val*0.05 }
+FEE           = ->(val) { val + 1 }
+PREMIUM       = ->(val) { val + 10 }
+DISCOUNT      = ->(val) { val * 0.90 }
+ROUND_TO_CENT = ->(val) { val.round(2) }
+PRESENT       = ->(val) { val.to_f }
 
 # Pre-define some rule set for some pricing scenarios
-REGULAR = %i(fee tax round_to_cent)
-PREMIUM = %i(fee premium tax round_to_cent)
-DISCOUNTED = %i(fee discount tax round_to_cent)
+REGULAR_SET    = [FEE, TAX, ROUND_TO_CENT, PRESENT]
+PREMIUM_SET    = [FEE, PREMIUM, TAX, ROUND_TO_CENT, PRESENT]
+DISCOUNTED_SET = [FEE, DISCOUNT, TAX, ROUND_TO_CENT, PRESENT]
 
-def price_calculator_for(rules:)
-  rules.map(&method(:rule)).inject(:>>)
+def apply_rules(rules:, base_price:)
+  rules.inject(:>>).call(base_price)
 end
 
-regular    = price_calculator_for(rules: %i(fee tax round_to_cent))
-premium    = price_calculator_for(rules: %i(fee premium tax round_to_cent))
-discounted = price_calculator_for(rules: %i(fee discount tax round_to_cent))
-
 amount = BigDecimal(100)
 
-puts "regular pay: #{regular.call(amount).to_f}" # => 106.05
-puts "premium pay: #{premium.call(amount).to_f}" # => 116.55
-puts "discounted pay: #{discounted.call(amount).to_f}" # => 95.45
+puts "regular:    #{apply_rules(rules: REGULAR_SET, base_price: amount)}"    # => 106.05
+puts "premium:    #{apply_rules(rules: PREMIUM_SET, base_price: amount)}"    # => 116.55
+puts "discounted: #{apply_rules(rules: DISCOUNTED_SET, base_price: amount)}" # => 95.45
diff --git a/proc_composition_1.rb b/proc_composition_1.rb
@@ -1,4 +1,3 @@
-
 # This lambda take one argument and return the same prefixed by "hello "
 greet = ->(val) { "hello #{val}" }
 # This lambda take one argument and return the upcased version

diff --git a/proc_composition_1.rb b/proc_composition_1.rb
@@ -1,6 +1,17 @@
-add_title = ->(val) { "value: #{val}" }
-titleize = ->(val) { val.split(' ').map(&:capitalize).join(' ') }
 
-present = add_title >> titleize
+# This lambda take one argument and return the same prefixed by "hello "
+greet = ->(val) { "hello #{val}" }
+# This lambda take one argument and return the upcased version
+upper = ->(val) { val.upcase }
 
-puts present["hello world"] # => Val: Hello World
+# So you can do
+puts greet["world"]    # => hello world
+puts upper["world"]    # => WORLD
+
+present = greet >> upper
+
+puts present["world"]  # => HELLO WORLD
+
+present = greet << upper
+
+puts present["world"]  # => hello WORLD
diff --git a/proc_composition-2.rb b/proc_composition-2.rb
@@ -1,5 +1,6 @@
 require "bigdecimal"
 
+# List of our individual pricing rules
 PRICE_RULE_DEFINTIONS = {
   tax: ->(val) { val + val*0.05 },
   fee: ->(val) { val + 1 },
@@ -8,10 +9,16 @@
   round_to_cent: ->(val) { val.round(2) }
 }
 
+# Some helper to pick a rule
 def rule(name)
   PRICE_RULE_DEFINTIONS[name]
 end
 
+# Pre-define some rule set for some pricing scenarios
+REGULAR = %i(fee tax round_to_cent)
+PREMIUM = %i(fee premium tax round_to_cent)
+DISCOUNTED = %i(fee discount tax round_to_cent)
+
 def price_calculator_for(rules:)
   rules.map(&method(:rule)).inject(:>>)
 end
@@ -22,6 +29,6 @@ def price_calculator_for(rules:)
 
 amount = BigDecimal(100)
 
-puts "regulat pay: #{regular.call(amount).to_f}"
-puts "premium pay: #{premium.call(amount).to_f}"
-puts "discounted pay: #{discounted.call(amount).to_f}"
+puts "regular pay: #{regular.call(amount).to_f}" # => 106.05
+puts "premium pay: #{premium.call(amount).to_f}" # => 116.55
+puts "discounted pay: #{discounted.call(amount).to_f}" # => 95.45
diff --git a/proc-composition-2.rb → proc_composition-2.rb b/proc-composition-2.rb → proc_composition-2.rb
diff --git a/proc-composition-2.rb b/proc-composition-2.rb
@@ -0,0 +1,27 @@
+require "bigdecimal"
+
+PRICE_RULE_DEFINTIONS = {
+  tax: ->(val) { val + val*0.05 },
+  fee: ->(val) { val + 1 },
+  premium: ->(val) { val + 10 },
+  discount: ->(val) { val * 0.90 },
+  round_to_cent: ->(val) { val.round(2) }
+}
+
+def rule(name)
+  PRICE_RULE_DEFINTIONS[name]
+end
+
+def price_calculator_for(rules:)
+  rules.map(&method(:rule)).inject(:>>)
+end
+
+regular    = price_calculator_for(rules: %i(fee tax round_to_cent))
+premium    = price_calculator_for(rules: %i(fee premium tax round_to_cent))
+discounted = price_calculator_for(rules: %i(fee discount tax round_to_cent))
+
+amount = BigDecimal(100)
+
+puts "regulat pay: #{regular.call(amount).to_f}"
+puts "premium pay: #{premium.call(amount).to_f}"
+puts "discounted pay: #{discounted.call(amount).to_f}"
diff --git a/proc_composition_simple1.rb → proc_composition_1.rb b/proc_composition_simple1.rb → proc_composition_1.rb
diff --git a/proc_composition_simple1.rb b/proc_composition_simple1.rb
@@ -0,0 +1,6 @@
+add_title = ->(val) { "value: #{val}" }
+titleize = ->(val) { val.split(' ').map(&:capitalize).join(' ') }
+
+present = add_title >> titleize
+
+puts present["hello world"] # => Val: Hello World
No results found