Presentation given at the 2010 Commercial Users of Functional Programming conference.

1. Naïveté vs. Experience How We Thought We Could Use Scala and Clojure, and How We Actually Did

2. Who

5. C, C++, Java, CLIPS, Clojure, Scala

7. Why

8. Java

9. Compression Potential

10. Compression Potential

11. Essential Boilerplate

12. Essential Boilerplate equals hashCode get set public Foo toString

13. Essential Boilerplate equals hashCode get set public Foo toString try catch finally ; { } @override static int System.out boolean . void import String Exception throws toString toString throws throws finally finally finally get get equals hashCode try } System.out boolean toString throws throws finally get public Foo catch finally ; int import String Exception throws toString get equals get toString try finally static import String toString throws finally equals try toString throws get finally String Exception hashCode finally { @override int void Exception toString throws finally hashCode toString throws finally public Foo finally int Exception @override static finally hashCode try throws throws static @override hashCode throws hashCode @override void toString toString int hashCode void finally finally public Foo int hashCode @override void toString toString int hashCode void finally finally public Foo int hashCode @override void toString toString int hashCode void finally finally public Foo int toString static finally equals try finally String toString throws finally toString finally

14. What

19. Java != JVM

20. Reprieve

22. Jython

23. Jess

24. Scala

25. Clojure

26. Groovy

27. Rhino

29. Jython

30. Jess

31. Scala

32. Clojure

33. Groovy

35. Clojure

46. (spouse != null ? " married to " + spouse.getFirstName() + "." : "." ); } }

48. (spouse != null ? " married to " + spouse.getFirstName() + "." : "." ); } }

50. (spouse != null ? " married to " + spouse.getFirstName() + "." : "." ); } }

52. (spouse != null ? " married to " + spouse.getFirstName() + "." : "." ); } }

54. override def toString(): String = firstName + " " + lastName +

55. (spouse match {

56. case None => "."

57. case Some(s) => " married to " + s.firstName + "."

58. });

59. } By default , Scala classes are immutable.

61. Disingenuous

63. ( toString [_]

64. ( str fname " " lname

65. ( when-let [n ( :fname spouse)]

66. ( str " married to " n))

67. ))) By default , Scala classes are immutable.

72. Everything is an Object

73. Functional Programming

74. List Comprehensions

75. Case Classes

76. Pattern Matching

77. Interoperability

78. Currying

79. Implicits

80. Architecture

81. services The Internet

82. services The Internet

83. services The Internet

84. services The Internet

85. services The Internet

86. services The Internet

87. services The Internet

88. services The Internet

89. The Internet

90. The Internet

91. The Internet

92. The Internet

93. Naïveté

95. Everything is an Object

96. Functional Programming

97. List Comprehensions

98. Case Classes

99. Pattern Matching

100. Interoperability

101. Currying

102. Implicits

105. List Comprehensions

106. Case Classes

107. Pattern Matching

108. Currying

109. Implicits

111. List Comprehensions

112. Pattern Matching

113. Currying

114. Experience

119. Disingenuous

120. Dis ingenuous

125. def get(ref:ReferenceParam):ComponentReturn = { ... }

126. ...

127. } By default , Scala classes are immutable.

129. def get(ref: ReferenceParam ): ComponentReturn = { ... }

130. ...

131. }

133. def get(ref: ReferenceParam ): ComponentReturn = { ... }

134. ...

140. def get(ref: ReferenceParam ): ComponentReturn = { ... }

141. ...

143. }

145. def get(ref: ReferenceParam ): ComponentReturn = { ... }

146. ...

148. }

149. RPCTypes LocalTypes CachedTypes DelayedTypes ... RPCTypes LocalTypes ... The Internet

153. When a tree falls in a lonely forest ... does it make a sound? – Charles Riborg Mann and George Ransom Twiss

154. If a pure function mutates some local data in order to produce an immutable return value, is that ok? – Rich Hickey

160. Optional Immutability

161. Weak Laziness

162. Less Functional

163. Grand Hierarchies

164. Literals-lite

166. Optional Immutability

167. Weak Laziness

168. Less Functional

171. My employer

172. Dean Wampler for feedback

173. Rich Hickey and Martin Odersky for Clojure and Scala

174. Chris Houser my co-author

175. Ryan Tomayko for the screaming face

176. The fam

178. Is Scala too complicated?

179. Best zombie movies?

180. Kobaia is de hundin?

181. Favorite hangout in Baltimore?

182. What's with the tie?