- (minus sign)

1. in identifiers, 150

2. operator:

   1. arithmetic, 7

   2. for collections, 191–192

   3. for maps, 54

   4. for type parameters, 269

   5. for types, 323

   6. left-associative, 154

   7. precedence of, 153

   8. unary (negation), 13, 152

-- operator

1. for collections, 191–192

2. for sets, 190

3. not used for arithmetic decrements, 7

-= operator

1. arithmetic, 7

2. for collections, 191–192

3. for maps, 53

--= operator, 191–192

_ (underscore)

1. for function parameters, 172

2. in case clauses, 34, 210–211, 214–215

3. in identifiers, 150

4. in imports, 91

5. in tuples, 58

_*, for arrays, 214

_=, in setter methods, 66

_1, _2, _3 methods (tuples), 57, 220

, (comma), in identifiers, 150

; (semicolon)

1. after statements, 5, 18–20

2. in identifiers, 150

3. inside loops, 26

: (colon)

1. followed by annotations, 233

2. in case clauses, 212–213

3. in class definitions, 64

4. in identifiers, 150

5. in operators, 153–154

6. in REPL commands, 4

7. in type parameters, 266

:: operator, 154

1. for collections, 192

2. for lists, 188–189, 191–192, 319–321

3. in case clauses, 215, 225

:::, :+ operators, 191–192

:+= operator, 191

! (exclamation mark)

1. in identifiers, 150

2. operator, 122–123, 152–153

!! operator, in shell scripts, 122

!= operator, 153

1. for types, 323

? (question mark), in identifiers, 150

?: operator, 18

??? method, 108

/ (slash)

1. in identifiers, 150

2. operator, 7, 153

/% method (BigInt), 7, 217

. (period), in identifiers, 150

' (backquote)

1. in case clauses, 212

2. in class definitions, 64

3. in identifiers, 90, 150

^ (caret)

1. in identifiers, 150

2. in Pascal, 163

3. operator, 7, 153

~ (tilde)

1. in identifiers, 150

2. operator, 152

' (single quote), " (double quote), in identifiers, 150

""", in regular expressions, 124

() (parentheses)

1. as value of Unit, 19–22

2. for annotations, 233

3. for apply method, 9–10

4. for array elements, 40

5. for curried parameters, 177

6. for functions, 31–32, 170–172, 178

7. for maps, 52

8. for primary constructors, 70

9. for tuples, 57

10. in case clauses, 215, 219

11. in identifiers, 150

12. in method declarations, 8, 65, 67

13. in regular expressions, 126

[] (square brackets)

1. for arrays, 40

2. for methods in traits, 135

3. for type parameters, 13, 264

4. in identifiers, 150

5. with qualifiers, 68–69, 89

{} (braces)

1. for block expressions, 21–22

2. for function arguments, 171

3. for structural types, 281

4. in class definitions, 64

5. in exports, 93

6. in formatted strings, 22

7. in identifiers, 150

8. in imports, 91

9. in pattern matching, 224–225

10. in REPL, 19

@ (at)

1. in annotations, 232

2. in case clauses, 221

3. in identifiers, 150

$ (dollar sign), in formatted strings, 22

* (asterisk)

1. in function parameters, 30

2. in identifiers, 90, 150

3. in imports, 90, 248

4. in Java, 8

5. operator, 7, 153, 307

*: operator, 188

**

1. in Fortran, 163

2. in identifiers, 150

(backslash), in identifiers, 150

& (ampersand)

1. in identifiers, 150

2. operator:

   1. arithmetic, 7

   2. for collections, 191–192

   3. for sets, 190

   4. for types, 278–279, 282

   5. precedence of, 153

&~ operator, 190–191

# (number sign)

1. for type projections, 74, 288

2. in identifiers, 150

#:: operator, 203

#&&, #<, #>, #>>, #|, #|| operators (in shell scripts), 123

% (percent sign)

1. in identifiers, 150

2. operator, 7, 153

+ (plus sign)

1. in identifiers, 150

2. operator:

   1. arithmetic, 7

   2. for collections, 191–192

   3. for maps, 53

   4. for type parameters, 269

   5. for types, 323

   6. precedence of, 153

   7. unary, 152

+: operator, 154, 191–192

++ operator

1. for collections, 191–192

2. for sets, 190

3. for tuples, 58

4. not used for arithmetic increments, 7

++:, ++=:, +=: operators, 191–192

++= operator

1. for array buffers, 40

2. for collections, 191–192

3. for maps, 53

+= operator

1. arithmetic, 7

2. assignment, 153

3. for array buffers, 40

4. for collections, 152, 191–192

< (left angle bracket)

1. in identifiers, 150

2. operator, 153

<- operator, 24, 26, 218–219

← identifier, 150

<: operator, 265–273, 289

<:< operator, 267, 311

<< operator, 7

<= operator, 153

= (equal sign)

1. in identifiers, 150

2. operator, 53, 153

= := operator, 267, 311–312

1. for types, 323

== operator, 153

1. attempting to override, 110

2. for collections, 185

3. for types, 110, 323

4. with incomporable objests, 110

===, =/= operators, 153

=> operator

1. for functions, 178

2. for self types, 143–144

3. in case clauses, 210

⇒ identifier, 150

> (right angle bracket)

1. in identifiers, 150

2. operator, 153

-> operator, 52, 153

>: operator, 266–267

>= operator, 153

>>, >>> operators, 7

| (vertical bar)

1. in case clauses, 210

2. in identifiers, 150

3. operator:

   1. arithmetic, 7

   2. for sets, 190–191

   3. for types, 277–278

   4. precedence of, 153

√ (square root), 150

(alarm clock emoji), 64

0 value, 64

0x prefix, in hexadecimal literals, 5

abstract keyword, 101–102, 131, 136, 299

abstract types, 286–287

1. bounds for, 289–290

2. made concrete in subclass, 281, 286

3. naming, 290

4. vs. type parameters, 287

addString method

1. of Iterable, 194

2. of Iterator, 202

adhocExtensions object, 104

after method, 125

aggregate method

1. of Iterable, 193

2. of Iterator, 202

algebraic data types, 224

aliases

1. for this, 144

2. for types, 186, 279–281

andThen method

1. of Function1, 177

2. of Future trait, 254

Annotation trait, 239

1. annotations, 231–240

2. @beanGetter, @beanSetter, 240

3. @BeanProperty, 66, 72

4. @BooleanBeanProperty, 234

5. @deprecated, 82, 238, 240

6. @deprecatedName, 45, 238

7. @experimental, 238

8. @field, 240

9. @getter, 240

10. @JsonbProperty, 233, 240

11. @main, 31, 81

12. @native, 236

13. @nowarn, 239

14. @Overrides, 99

15. @param, 240

16. @SerialVersionUID, 121, 234

17. @setter, 240

18. @tailrec, 237

19. @targetName, 151

20. @threadUnsafe, 238

21. @throws, 235

22. @transient, 235

23. @unchecked, 238–239

24. @uncheckedVariance, 239

25. @varargs, 235

26. @volatile, 236

27. arguments of, 233

28. for compiler optimizations, 236–238

29. for errors and warnings, 238–239

30. implementing, 239–240

31. in Java, 232–236

32. meta-annotations for, 240

33. order of, 233

anonymous functions, 170–172

Any class, 107, 109

1. asInstanceOf method, 99, 107, 214

2. isInstanceOf method, 99, 107

AnyRef class, 107, 213

1. == method, 110

2. eq, equals methods, 109

3. notify, notifyAll, synchronized, wait methods, 107

AnyVal class, 106, 111, 213

append method

1. of Appendable, 281

2. of StringBuilder, 58

3. vs. intersection types, 282

Appendable interface (Java), 132, 281–282

application objects, 81

apply method, 9–10, 80, 155, 156, 159

1. of Array, 10, 80

2. of BigInt, 10

3. of case classes, 219

4. of collections, 185

5. of Future object, 251, 259

6. of PartialFunction, 224

7. of Process, 123

8. of StringOps, 9

applyDynamic method

1. of Dynamic, 160–161

2. of Selectable, 163

applyDynamicNamed method

1. of Dynamic, 160–161

2. of DynamicProps, 161

array buffers, 40–41

1. adding/removing elements of, 40–41

2. appending collections to, 40

3. converting to arrays, 41

4. displaying contents of, 44

5. empty, 40

6. largest/smallest elements in, 44

7. sorting, 44

8. transforming, 42–43

9. traversing, 41–42

Array class, 39–40, 267

1. apply method, 80

2. corresponds method, 177

3. mkString method, 44

4. ofDim method, 46

5. sortInPlace method, 44

6. toBuffer method, 41

Array companion object, 10, 216

ArrayBuffer class, 40–41, 184

1. max, min, mkString methods, 44

2. mutable, 187

3. serializing, 122

4. sorted, sortWith methods, 44

5. toArray method, 41

ArrayList class (Java), 40, 47, 185

ArrayOps class, 45

arrays, 39–48

1. converting to array buffers, 41

2. displaying contents of, 44

3. fixed-length, 39–40

4. function call syntax for, 155

5. generic, 267

6. immutable, 213, 270

7. interoperating with Java, 47–48

8. invariant, 270

9. largest/smallest elements in, 44

10. multidimensional, 46–47

11. pattern matching for, 214

12. ragged, 47

13. sorting, 44

14. transforming, 42–43

15. traversing, 41–42

16. vs. lists, 185

Arrays class (Java), 47

ArraySeq class, 45

ArrayStoreException, 270

as keyword, 91

ASCII characters, 150

asInstanceOf method (Any), 99, 107, 214

asJava method (CollectionConverters), 47, 55

asJavaXxx, asScalaXxx functions (CollectionConverters), 205

asScala method (CollectionConverters), 48, 55, 204, 218

assignments, 21–22, 153

1. no chaining of, 22

2. precedence of, 153

3. right-associative, 154, 191

4. value of, 21–22

asynchronous APIs, 257

auto tupling, 58

AutoCloseable interface (Java), 132

automatic conversions. See implicit conversions

Await object, 248

bash shell, 123

@beanGetter, @beanSetter annotations, 240

@BeanProperty annotation, 66

1. generated methods for, 72

before method, 125

BigDecimal class, 6, 8

BigInt class, 6–9

1. /% method, 7, 217

2. pow method, 163

3. unary_- method, 13

BigInt companion object

1. apply method, 10

2. probablePrime method, 9

binary files, reading, 120

binary functions, 174, 197

binary operators, 152–155

binary trees, 54

BitSet class, 190, 194

blocking calls, 248

blocking keyword, 258

blocks, 21–22

Boolean type, 5

1. reading, 23

@BooleanBeanProperty annotation, 234

Breaks object, break method, 25

Buffer class, 334

buffered method

1. of BufferedIterator, 202

2. of Source, 119

BufferedInputStream class (Java), 146

BufferedIterator trait, 202

Byte type, 5

1. arrays of, 120

2. reading, 23

C++ programming language

1. ?: operator in, 18

2. arrays in, 40

3. assignments in, 22

4. construction order in, 106

5. constructors in, 69

6. functions in, 27

7. implicit conversions in, 307

8. linked lists in, 188

9. loops in, 23, 42

10. methods in, 78, 105, 236

11. multiple inheritance in, 130

12. namespaces in, 86

13. protected fields in, 105

14. reading files in, 119

15. statements in, 21

16. switch in, 210–211

17. virtual base classes in, 130

18. void in, 19, 21, 108

cached thread pool, 259

callback hell, 250

call-by-name parameters, 179

case classes, 219–226

1. declaring, 219

2. default methods of, 219

3. extending other case classes, 220

4. formatted as JSON, 330

5. modifying properties in, 220

6. sealed, 222

case clause, 210–226

1. _ in, 210–211, 214–215

2. : in, 212–213

3. :: in, 215, 225

4. `...` in, 212

5. () in, 215

6. =>, | in, 210

7. catch-all pattern for, 210–211

8. enclosed in braces, 224–225, 250

9. enum in, 223

10. infix notation in, 225–226

11. order of, 212

12. variables in, 211–212

case objects, 219

casts, 99

catch statement, 34–35

1. as a partial function, 225

chaining

1. assignments, 22

2. auxiliary constructors, 72

3. futures, 251

4. methods, 285, 291

5. packages, 88

Char type, 5, 23

character sets, 120

characters

1. common, in two strings, 6

2. in identifiers, 150

3. reading, 23, 118–119

4. sequences of, 13

5. uppercase, 13

circular dependencies, 32

class files, 31

1. analyzing, 341

class keyword, 63

class path, 124

classes, 11, 63–74

1. abstract, 101–102, 134

2. abstract types in, 286

3. annotated, 232

4. combined with primary constructor, 72

5. companion objects to, 9, 74, 78–79, 308

6. concrete, 137

7. constructed, for package-level functions, 89

8. definitions of:

   1. executing statements in, 70

   2. using traits in, 133

9. equality checks in, 109

10. extending, 79, 98, 104

    1. Java classes, 101

    2. multiple traits, 132

    3. only one superclass, 130, 137

11. extension methods in, 304

12. final, 98, 104

13. generic, 264, 268

14. granting access to, 68–69

15. immutable, 7

16. importing members of, 90

17. inheritance hierarchy of, 106–109

18. inlined, 111–112

19. interoperating with Java, 66

20. linearization of, 139

21. names of, 64, 150

22. nested, 73–74

23. open, 104

24. primitive types and, 5

25. properties of, 65, 67

26. recompiling, 137

27. sealed, 104–105, 222, 330–331

28. serializable, 121, 234

29. type parameters in, 264

30. visibility of, 64

classOf method (scala.Predef), 99

ClassTag trait, 267

close method

1. of PrintWriter (Java), 120

2. of Source, 118

closures, 174–175

codeOf function (compiletime), 324–325, 336

coll method

1. of Iterator, 202

2. of Seq, 195

collect method

1. of Future trait, 254

2. of Iterable, 193

3. of IterableOps, 224

4. of Iterator, 202

5. with partial functions, 197

CollectionConverters object, 47, 55, 204–205, 218

collections, 183–205

1. adding elements of, 190–192

2. appending to array buffers, 40

3. applying functions to all elements of, 173, 193–197

4. combining, 200–201

5. companion objects of, 185

6. constructing in a loop, 26, 42

7. converting to specific type, 194

8. filtering, 193

9. folding, 193, 198–200

10. hierarchy of, 45, 184–185

11. immutable, 185–186

12. instances of, 185

13. interoperating with Java, 204–205

14. iterators for, 201–202

15. methods for, 193–195

16. mutable, 152, 185–186, 191–192

17. ordered, 184, 190

18. reducing, 193, 197–198

19. removing elements of, 190–192

20. scanning, 200

21. serializing, 122

22. sorted, 184

23. traits for, 184–185

24. traversing, 24, 42, 236–237

25. unevaluated, 204

26. unordered, 184, 190, 192

combinations method

1. of Iterator, 202

2. of Seq, 195

companion objects, 9, 74, 78–79

1. extension methods in, 305

2. implicits in, 308

3. of collections, 185

Comparable interface (Java), 265, 326

Comparator interface (Java), 239, 326

compareTo method, 265

compiler

1. implicits in, 308, 312–313

2. -language:implicitConversions flag, 307

3. -language:postfixOps flag, 153

4. nested type expressions in, 288

5. optimizations in, 236–238

6. Scala annotations in, 232

7. -Wconf, -Wunused:nowarn flags, 239

8. -Xprint flag, 308

9. -Yexplicit-nulls flag, 108

10. -Ysafe-init flag, 106

compiler plugin, 232

compile-time errors, 23

CompletableFuture class (Java), 258

CompletionStage interface (Java), 247

Component class (Java), 145

compose method (Functionl), 177

comprehensions, 27

computations with side effects, 248

concat method (StringOps), 13

ConcurrentHashMap class (Java), 186

console

1. input from, 23, 119

2. printing to, 22

ConstantAnnotation trait, 240

constants. See values

constructor proxy methods, 80

constructors

1. auxiliary, 69–70, 100

   1. chaining, 72

   2. eliminating, 71

2. executing, 78

3. order of, 105–106, 138–139

4. parameterless, 71

5. parameters of, 73, 234

   1. annotated, 240

6. primary, 69–73, 100

   1. annotated, 233

   2. default parameters in, 71

   3. private, 73

7. superclass, 100–101

8. vals in, 106

constValueXxx methods (scala.compiletime), 329

Container class (Java), 145

contains method, 52

1. of BitSet, 190

2. of Iterator, 202

3. of Seq, 195

containsSlice method

1. of Iterator, 202

2. of Seq, 195

context bounds, 266, 300

context functions, 309–311

context parameters, 10, 296–299

control abstractions, 178–179

Conversion class, 306

copy method (case classes), 220

corresponds method (Array), 177

count method

1. of Iterable, 193

2. of Iterator, 202

3. of StringOps, 13

Coursier tool, 124

curried method, 177

Curry, Haskell Brooks, 176

currying, 176–177

debugging

1. implicit conversions, 309

2. reading from strings for, 120

3. reporting types for, 45

4. using macros for, 336

decrements, 7

def keyword, 27, 171

1. abstract, 103

2. overriding, 102–103

3. parameterless, 102

default statement, 210

definitions, 26

delegate method (Future object), 256

dependent types, 287–288

@deprecated annotation, 82, 238, 240

@deprecatedInheritance, @deprecatedOverriding annotations, 238

@deprecatedName annotation, 45, 238

derives keyword, 111, 331

destructuring of tuples, 215

diamond inheritance problem, 130–131

diff method

1. of Iterator, 202

2. of Seq, 195

3. of sets, 190

directories

1. naming, 15

2. packages and, 86

3. traversing, 120–121

division, quotient and remainder of, 7, 217

do loop, 23

domain-specific languages, 149

dot notation, 7

Double type, 5

1. reading, 23

drop, dropWhile methods

1. of Iterable, 193

2. of Iterator, 202

dropRight method (Iterable), 194

duck typing, 283

Duration object, 248

dynamic invocation, 159–162

Dynamic trait, 159

dynamically typed languages, 283

DynamicProps class, 161

Eiffel programming language, 67

EmptyTuple object, 215

end keyword, 23, 28

end method, 125

endsWith method

1. of Iterator, 202

2. of Seq, 195

enum keyword, 81–83, 330–331

1. parameterized, 83, 223–224

Enumeration class, 81–83

1. enumerations, 81–83

2. parameterized, 223–224

3. type parameters in, 223

eq method (AnyRef), 109

equals method

1. of AnyRef, 109–110

2. of case classes, 219

3. of value classes, 111

4. overriding, 110

5. parameter type of, 109

Equiv class, 328

erasedValue method (scala.compiletime), 325, 330

error method (scala.compiletime), 325

1. error messages

2. for implicit conversions, 309, 312

3. generated with annotations, 238

4. suppressed, 239

5. with override modifier, 98

errors

1. MatchError, 210, 217–218

2. NotImplementedError, 108

3. OutOfMemoryError, 203

escape hatch, 150

eta expansion, 171

evidence objects, 312

exceptions, 33–36

1. ArrayStoreException, 270

2. catching, 34

3. checked, in Java, 33, 235

4. IllegalArgumentException, 33

5. IllegalStateException, 257

6. InterruptedException, 249

7. IOException, 235

8. LoggedException, 140, 144

9. NoSuchElementException, 252

10. NumberFormatException, 119, 250

execution contexts, 258–259

ExecutionContext trait, 246, 310

Executor interface (Java), 246

Executors class, 259

exists method

1. of Iterable, 193

2. of Iterator, 202

@experimental annotation, 238

export statement, 92–93

1. given in, 303

expressions

1. annotated, 233

2. conditional, 18–20

3. traversing values of, 24

4. type of, 18

5. vs. functions, 171

extends keyword, 82, 98, 131, 279

extension keyword, 303–306

extension methods, 303–306

1. used by compiler, 308

extractors, 126, 155–159, 216–217

f prefix, in formatted strings, 22

failed method

1. of Future object, 256

2. of Future trait, 253–254

Failure class, 249

failure method (Promise), 257

fallbackTo method (Future trait), 253–254

fall-through problem, 210

false value, 64

@field annotation, 240

fields

1. abstract, 102, 137

2. annotated, 232

3. concrete, 102, 136–137

4. for primary constructor parameters, 72, 234

5. getter/setter methods for, 66, 72

6. hash codes of, 110

7. object-private, 68–69, 71

8. overriding, 102–103, 137

   1. in subclasses, 98

9. protected, 105

10. public, 65

11. static, 78

12. transient, 235

13. volatile, 236

files

1. appending, 123

2. binary, 120

3. naming, 15

4. packages and, 86

5. processing, 117–124

6. reading, 118–119

7. redirecting input/output from/to, 123

8. source, 89

9. writing, 120

Files class (Java), 118, 120–121

filter method, 43, 57, 174

1. applied to lazy lists, 204

2. of Future trait, 254

3. of Iterable, 193

4. of Iterator, 202

filterNot method

1. of Iterable, 193

2. of Iterator, 202

final keyword, 67, 98

finally statement, 34–35

find method

1. of Future object, 256

2. of Iterator, 202

findXxxIn methods (Regex), 124

firstCompletedOf method (Future object), 256

flatMap method, 195–197

1. of Future, 252

2. of Iterable, 193

3. of Iterator, 202

4. of Try, 253

flatten method (Future trait), 254

Float type, 5

1. reading, 23

fluent interfaces, 286

fold method

1. of Iterable, 193

2. of Iterator, 202

foldLeft method, 180

1. of Future object, 256

2. of Iterable, 193, 198–199, 271

3. of Iterator, 202

foldRight method

1. of Iterable, 193, 199

2. of Iterator, 202

for loop, 24–26

1. constructing collections in, 26, 42

2. enhanced (Java), 42

3. for arrays, 41–43

4. for futures, 252

5. for maps, 54

6. for regex groups, 126

7. given in, 301

8. guards in, 219, 252

9. Option type in, 56

10. pattern matching in, 218

11. range-based (C++), 42

for case loop, 218

forall method

1. of Iterable, 193

2. of Iterator, 202

foreach method, 57, 174, 197

1. of Future, 253

2. of Future trait, 254

3. of Iterable, 193

4. of Iterator, 202

fork-join pool, 258

formatted strings, 22

Fortran programming language, 163

Fraction class, 156, 306–308

Fraction companion object, 308

Fractional class, 328

fragile base class problem, 98

fromOrdinal method (enumerations), 82

FromString class, 328

fromString method (Source), 120

fromTry method (Future object), 256

fromURL method (Source), 120

Function1 trait, 177

functional programming languages, 169

functions, 27–29, 169–180

1. anonymous, 170–172

2. as method parameters, 13, 170

3. binary, 174, 197

4. calling, 8–9, 170

5. context, 309–311

6. converting to Java interfaces, 176

7. curried, 176–179, 296

8. declaring, 27

9. exiting immediately, 28

10. for all elements of a collection, 173

11. generic, 264–265, 267

12. higher-order, 172–174

13. identity, 312

14. mapping, 195–197

15. names of, 150, 306

16. package-level, 89

17. parameterless, 31–32, 178–179

18. parameters of, 27

    1. call-by-name, 179

    2. default, 29

    3. named, 29

    4. other functions as, 171–172

    5. type deduction in, 172

    6. variable, 30

19. partial, 197, 224–225

20. passing to another function, 170–172

21. polymorphic, 273–274

22. recursive, 27–30

23. return type of, 5, 27, 29

24. return value of, 178–179

25. scope of, 174

26. single-argument, 172, 269

27. storing in variables, 170

28. syntax of, 155

29. type parameters in, 264–265

30. type-level, 334

31. unary, 177–178

32. variance of, 269

33. vs. methods, 171

Future companion object, 255–257

1. apply method, 251, 259

2. delegate method, 256

3. failed method, 256

4. find method, 256

5. firstCompletedOf method, 256

6. foldLeft method, 256

7. fromTry method, 256

8. never object, 257

9. reduceLeft method, 256

10. successful method, 256

11. traverse method, 255

12. unit value, 257

Future interface (Java), 247

future method (Promise), 257

Future trait, 246–259, 310

1. andThen method, 254

2. collect method, 254

3. failed, fallbackTo methods, 253–254

4. filter method, 254

5. flatMap method, 252

6. flatten method, 254

7. foreach method, 253–254

8. isCompleted method, 248

9. map method, 251–252

10. onComplete method, 250

11. onFailure method, 250

12. onSuccess method, 250

13. ready method, 249

14. recover, recoverWith methods, 253–254

15. result method, 249

16. transform, transformWith methods, 254

17. value method, 248

18. zip, zipWith methods, 254–255

futures, 246–259

1. blocking waits for, 250

2. chaining, 251

3. concurrent, 246

4. creating, 246

   1. delayed, 252

5. execution context of, 258–259

results of, 247, 257

tasks of:

1. composing, 251–253

2. failing, 248

3. running, 246–248

transformations of, 253–255

generators, 26

generic arrays, 267

generic classes, 264

1. methods used under certain conditions

   1. in, 268

generic functions, 264–265, 267

generic methods, 264

generic types

1. erased, in JVM, 213, 267

2. variance of, 269–273

get method

1. of Map, 52, 56

2. of Try, 249

getLines method (Source), 118, 203

getOrElse method (Map), 52, 56

getOrElseUpdate method (Map), 186

@getter annotation, 240

getXxx methods, 66, 234

given keyword, 297, 299–303

1. export with, 303

2. extension methods in, 305

3. import with, 302–303

4. match with, 301

5. with for, 301

given values, 266

groupBy, groupMap, groupMapReduce methods

(Iterable), 194, 197

grouped method

1. of Iterable, 194, 201

2. of Iterator, 202

guards, 26, 42, 211

1. in for statements, 219, 252

2. variables in, 211

hash codes, 107, 110

hash maps, 55

hash sets, 189

hash tables, 54

hashCode method, 189

1. of AnyRef, 110

2. of case classes, 219

3. of value classes, 111

4. overriding, 110

Hashing class, 328

Haskell programming language, 29, 327

hasNext method

1. of Iterable, 201

2. of Iterator, 133

head method

1. of BufferedIterator, 202

2. of Iterable, 193

3. of lists, 188–189

4. of Source, 119

headOption method (Iterable), 193

heterogeneous lists, 319–321

hexadecimal literals, 5

Hindley-Milner algorithm, 29

HTTP (Hypertext Transfer Protocol), 120

identifiers, 150

identity functions, 312

if expression, in loop generators, 26, 42

if/else expression, 18–20, 34

IllegalArgumentException, 33

IllegalStateException, 257

immutability, 7

implements keyword, 131

implicit conversions, 47, 149, 306–309

1. ambiguous, 307

2. debugging, 309

3. for strings to ProcessBuilder objects, 122

4. importing, 308–309

5. naming, 306

6. rules for, 307–308

7. unwanted, 307–308

8. used by compiler, 308

implicit keyword, 14, 46

implicit parameters, 14

@implicitNotFound annotation, 312–313

import statement, 86, 90–92

1. given in, 302–303

2. implicit, 92

3. location of, 91

4. overriding, 92

5. selectors for, 91

6. wildcards in, 8, 90–91

increments, 7

IndexedSeq trait, 13, 184, 187

1. immutable, 186

indexXxr methods

1. of Iterator, 202

2. of Seq, 195

infix notation

1. for anonymous functions, 171

2. for operators, 151–153

3. for type parameters, 264

4. in case clauses, 225–226

inheritance, 97–112

1. diamond, 130–131

2. hierarchy of, 106–109

3. multiple, 129–131

4. vs. composition, 93

init method (Iterable), 193

inline code, 323–326

inline keyword, 324–326

instances, 81

1. comparing, 111, 327

2. constructing, 162, 185

3. creating on the fly, 282

4. dependent types and, 288

5. given, 299–301, 328–329

6. state of, 82

Int type, 5, 265, 268

1. immutability of, 7

2. no null value in, 108

3. reading, 23

integer literals, 5

integer types, 322, 334

interfaces, 130

1. fluent, 286

2. rich, 133

InterruptedException, 249

intersect method

1. of Iterator, 202

2. of Seq, 195

3. of sets, 190

4. of StringOps, 6

intersection types, 144, 278–279, 282

intertwining classes and constructors, 100

IOException, 235

isCompleted method

1. of Future, 248

2. of Promise, 258

isDefinedAt method (PartialFunction), 224

isEmpty method

1. of Iterable, 193

2. of Iterator, 202

isFailure method (Try), 249

isInstanceOf method (Any), 99, 107, 212

IsIterable, IsIterableOnce, IsMap, IsSeq classes, 328

isSuccess method (Try), 249

istream::peek function (C++), 119

Iterable trait, 13, 45, 184, 332–334

1. map method, 333

2. methods of, 193–195, 201, 271

IterableOnce trait, 13, 45

IterableOps trait, 224

iterator method (collections), 201

Iterator trait, 133, 184

iterators, 118, 201–202

1. constructing lazy lists from, 203

2. fragility of, 202

Jakarta EE, 232

Java programming language

1. ?: operator in, 18

2. annotations in, 232–236

3. arrays in, 40, 46–47, 185, 270

4. assignments in, 22

5. checked exceptions in, 33, 235

6. classes in, 98

   1. hierarchy of, 73

   2. serializable, 121

7. closures in, 175

8. collections in, 185

9. comparing objects in, 110

10. completable futures in, 258

11. ConcurrentHashMap in, 186

12. construction order in, 106

13. constructors in, 69

14. enumerations in, 82

15. fields in, 65, 105

16. file processing in, 118

17. functional (SAM) interfaces in, 175

18. futures in, 247

19. generic types in, 272

20. hashCode method in, 189

21. interfaces in, 129–132, 141–143

22. interoperating with Scala:

    1. arrays, 47–48

    2. classes, 66, 101, 232

    3. collections, 204–205

    4. maps, 55, 218

    5. methods, 235

    6. traits, 141–143

23. lambda expressions in, 175

24. linked lists in, 185, 188

25. loops in, 23, 42

26. maps in, 185

27. methods in, 78, 99, 105

    1. static, 9, 27

28. missing values in, 268

29. modifiers in, 236

30. new operator in, 40

31. no multiple inheritance in, 130

32. no operator overloading in, 8

33. no variance in, 239

34. null value in, 108

35. packages in, 86, 88–89

36. primitive types in, 40, 106

37. reading files in, 119–120

38. statements in, 21

39. superclass constructors in, 101

40. synchronized in, 107

41. toString method in, 45

42. traversing directories in, 120–121

43. try-with-resources statement in, 36

44. type checks and casts in, 99

45. void in, 19, 21, 108

46. wildcards in, 272

Java AWT library, 145

java.io.BufferedInputStream class, 146

java.io.PrintWriter class, 120

java.lang package, 92

java.lang.Appendable interface, 132, 281–282

java.lang.AutoCloseable interface, 132

java.lang.Enum class, 82

java.lang.Object class, 107

java.lang.ProcessBuilder class, 48

java.lang.String class, 6, 40

java.lang.Throwable class, 33

java.math.BigX.rx classes, 6

java.nio.file.Files class, 118, 120–121

java.util package, 205

java.util.ArrayList class, 40, 47, 185

java.util.Arrays class, 47

java.util.Comparator class, 239

java.util.concurrent.CompletableFuture class, 258

java.util.concurrent.CompletionStage interface, 247

java.util.concurrent.Executor interface, 246

java.util.concurrent.Executors class, 259

java.util.concurrent.Future interface, 247

java.util.LinkedList class, 185

java.util.List interface, 47, 185

java.util.Properties class, 55, 218

java.util.RandomAccess interface, 185

java.util.Scanner class, 59, 119

JavaBeans specification, 145

JavaScript programming language

1. arrays in, 40, 46

2. closures in, 175

3. duck typing in, 283

4. loops in, 42

5. methods in, 78

6. translating from Scala, 10

javax.swing.JTextArea class, 281

JButton, JComponent classes (Swing), 145

JDK (Java Development Kit), source code for, 226

JSON companion object, 331

JSON trait, 305–306, 328–330

JSON-B framework, 232

@JsonbProperty annotation, 233, 240

JTextArea class (Java), 281

JUnit framework, 232

JVM (Java Virtual Machine)

1. arrays in, 40

2. classes in, 137

3. generic types in, 213, 267

4. stack size of, 237

5. terminating, 246

6. volatile fields in, 236

keySet method (Map), 54

lambda expressions, 175, 273–274

last, lastOption methods (Iterable), 193

lastIndexOf, lastIndexOfSlice methods

1. of Iterator, 202

2. of Seq, 195

lazy keyword, 32–33

lazy lists, 202–204

lazy values, 238

lazyZip method

1. of Iterable, 194

2. of Iterator, 202

length method

1. of Iterable, 193

2. of Iterator, 202

lift method, 126

linearization, 139

LinearSeq trait, 13

lines, 118

linked hash sets, 190

LinkedHashMap class, 55

LinkedList class (Java), 185

List class, 332

1. immutable, 186–187

List interface (Java), 47, 185

list method (java.nio.file.Files), 121

ListBuffer class, 187

lists, 188–189

1. adding elements of, 191–192

2. constructing, 154, 188

3. destructuring, 189

4. empty, 108, 319

5. heterogeneous, 227, 319–321

6. immutable, 202, 271

7. lazy, 123, 202–204

8. linked, 184

9. pattern matching for, 215, 225

10. removing elements of, 191–192

11. traversing, 188

12. vs. arrays, 185

literal types, 283–284, 322–323

literals, 5

log messages

1. adding timestamp to, 134

2. truncating, 134, 137

3. types of, 133

LoggedException trait, 140, 144

Logger trait, 133

Long type, 5

1. reading, 23

loops, 23–26

1. breaking out of, 25

2. for collections, 24

3. variables within, 26

4. vs. folding, 199–200

macros, 335–339

main method, 81

@main annotation, 31, 81, 232

map method, 43, 57, 173

1. applied to lazy lists, 204

2. of Future, 251–252

3. of Iterable, 193–197, 333

4. of Iterator, 202

5. of Try, 253

Map trait, 52, 184–186

1. get, getOrElse methods, 52, 56

2. immutable, 186

3. keySet, values methods, 54

mapInPlace method

1. of ArrayBuffer, 196

2. of Iterable, 193

3. of Iterator, 202

maps, 51–59

1. blank, 52

2. constructing, 52

   1. from collection of pairs, 59

3. function call syntax for, 155

4. interoperating with Java, 55

5. inverting, 54

6. iterating over, 54

7. keys of:

   1. checking, 52

   2. removing, 53

   3. visiting in insertion order, 55

8. mutable/immutable, 52–53, 55, 185

9. sorted, 55

10. traversing, 218

11. updating values of, 53

12. values of, 52

match expression, 58, 210–211, 222

1. given in, 301

2. on types, 318–319

3. processing Try instances with, 249

4. using with inline, 326

Match class, 126

match types, 318–319

Matchable trait, 18, 213–214

matched method, 125

MatchError, 210, 217–218

matches method (String), 124, 338

Math class, 8

mathematical functions, 8, 13

max method

1. of ArrayBuffer, 44

2. of Iterable, 193

3. of Iterator, 202

maxBy, maxByOption, maxOption methods

1. of Iterable, 193

2. of Iterator, 202

MessageFormat class (Java), 298

methods

1. abstract, 102–103, 131, 135–136, 141–143, 299

2. abundance of, 11, 14

3. accessor, 65

4. annotated, 232

5. as arithmetic operators, 7

6. calling, 2, 5, 8–9, 64, 66–67, 135

7. chained, 285, 291

8. clashes of, in sub- and superclasses, 98

9. co-/contravariant, 312

10. constructor proxy, 80

11. declaring, 27

12. executed lazily, 203

13. extension, 303–306

14. final, 99, 109, 237

15. for primary constructor parameters, 72

16. generic, 264

17. getter/setter, 65–68, 102

18. modifiers for, 89–90

19. mutator, 65

20. names of, 7, 13

    1. misspelled, 98

21. overriding, 98–99, 102–103, 135–136

22. parameterless, 8, 64, 102

23. parameters of, 7, 264, 271, 286

    1. functions for, 13, 170

    2. implicit, 14

    3. using, 267

    4. wrong type, 98

24. private, 237

25. protected, 105

26. public, 66

27. return type of, 271, 285

28. return value of, 264

29. static, 78

30. type parameters in, 264–265

31. used under certain conditions, 268

32. variable-argument, 235

33. vs. functions, 171

Meyer, Bertrand, 67

min method

1. of ArrayBuffer, 44

2. of Iterable, 193

3. of Iterator, 202

4. of scala.math, 8

minBy, minByOption, minOption methods

1. of Iterable, 193

2. of Iterator, 202

MirroredXxr types, 329, 331

mirrors, 328–330

mkString method

1. applied to lazy lists, 204

2. of Array, ArrayBuffer, 44

3. of Iterable, 194

4. of Iterator, 202

5. of Source, 118–119

ML programming language, 29

mulBy function, 172, 175

multiple inheritance, 129–131

multiply method (Java), 151

multiversal equality, 110–111

@native annotation, 236

negation operator, 13

nested structures, 221–222

never object (Future object), 257

new keyword, 40, 73

1. omitting, 219, 221

2. required, 101, 134

newline character

1. in long statements, 20

2. in printed values, 22

3. inside loops, 26

next method

1. of Iterable, 201

2. of Iterator, 133

Nil list, 108, 188–189, 239

None object, 56–57, 219, 222

NonLocalReturns object, 28, 180

NoSuchElementException, 252

Nothing type, 34, 108, 272

notify, notifyAll methods (AnyRef), 107

NotImplementedError, 108

@nowarn annotation, 239

Null type, 108

null value, 64, 108, 268

NumberFormatException, 119, 250

numbers

1. classes for, 13

2. converting:

   1. between numeric types, 6, 10

   2. to arrays, 119

3. greatest common divisor of, 164

4. invoking methods on, 5

5. literals for, 5

6. random, 9

7. ranges of, 13

8. reading, 23, 119

9. sums of, 44

Object class (Java), 107

object keyword, 78–83, 286

objects, 77–83

1. adding traits to, 133

2. companion, 9, 74, 78–79, 185, 308

3. comparing, 110–111

4. constructing, 10, 64, 78, 134

5. default methods for, 189

6. equality of, 109–110

7. evidence, 312

8. exporting, 92–93

9. extending class or trait, 79

10. extension methods in, 304

11. extracting values from, 216

12. given, 298

13. importing members of, 90

14. nested, 221

15. nested classes in, 73–74

16. no type parameters for, 271

17. pattern matching for, 212

18. serializing, 121, 278

19. testing whether belongs to a given class, 99

20. variance of, 270

ofDim method (Array), 46

onComplete, onFailure, onSuccess methods (Future), 250

opaque types, 112, 214

open keyword, 104

1. operators, 149–155

2. arithmetic, 7–8

3. assignment, 153–154

4. associativity of, 154

5. binary, 152–155

6. for adding/removing elements, 190–192

7. infix, 151, 153

8. overloading, 8

9. postfix, 152–153

10. precedence of, 153–154

11. unary, 152–153

optimization, 236–238

Option class, 52, 56–57, 125, 156, 193, 219, 222

1. orNull method, 268

2. using with for, 56

Ordering class, 44, 328

ordinal method (enumerations), 81

orNull method (Option), 268

OutOfMemoryError, 203

override keyword, 98–99, 102–103, 136

1. omitted, 102, 131

@Overrides annotation, 99

package objects, 8

package.scala file, 89

package-level functions, 89

packages, 85–92

1. adding items to, 86

2. chained, 88

3. defined in multiple files, 86

4. extension methods in, 304

5. importing, 8, 90–92

   1. always, 92

   2. selected members of, 91

6. modifiers for, 89–90

7. naming, 88, 92

8. nested, 87–88

9. top-of-file notation for, 88

padTo method

1. of Iterator, 202

2. of Seq, 195

Pair class, 272

@param annotation, 240

parameters

1. annotated, 232

2. contex, 10, 296–299

3. curried, 311

4. deprecated, 238

5. implicit, 14

6. named, 220

partial functions, 197, 224–225

PartialFunction class, 224–225

partition method

1. of Iterable, 193

2. of Iterator, 202

3. of StringOps, 58

Pascal programming language, 163

pattern matching, 209–226

1. +: operator and, 192

2. by type, 212–213

3. classes for. See case classes

4. extractors in, 156

5. extractors with, 216

6. failed, 156

7. for arrays, 214

8. for lists, 189, 215, 225

9. for maps, 54

10. for nested structures, 221–222

11. for objects, 212

12. for tuples, 58, 215

13. for types, 318–319

14. guards in, 211

15. in for expressions, 218

16. in variable declarations, 217–218

17. not exhaustive, 239

18. Option type with, 219

19. partial functions with, 224–225

20. regular expressions in, 216

21. sealed classes and, 105

22. variables in, 211–212

23. vs. type checks and casts, 99

permutations method

1. of Iterable, 201

2. of Iterator, 202

3. of Seq, 195

piping, 123

Point class, 328

polymorphism, 221, 273–274

postfix operators, 152–153

pow function (scala.math), 8, 27, 163

Predef object

1. always imported, 92, 99, 186

2. classOf method, 99

3. implicits in, 311

prefixLength method

1. of Iterator, 202

2. of Seq, 195

primitive types, 5

1. arrays of, 40

print function, 22, 119

printf function, 120

println function, 22

PrintWriter class (Java), 120

PriorityQueue class, 187

private keyword, 64–74, 89

probablePrime method (BigInt), 9

procedures, 29

process control, 122–124

Process object, 123

ProcessBuilder class (Java), 48

1. constructing, 123

2. implicit conversions to, 122

product method

1. of Iterable, 193

2. of Iterator, 202

Product trait, 220, 329

product types, 220, 224

programs

1. entry point of, 31, 81

2. implicit imports in, 92

3. piping, 123

4. readability of, 8

5. self-documenting, 290

Promise trait, 257–258

promises, 257–258

properties, 65

1. read-only, 67

2. write-only (not possible), 68

Properties class (Java), 55, 218

property change listeners, 145

protected keyword, 89, 105

public keyword, 64, 89

PushbackInputStreamReader class (Java), 119

putIfAbsent method (Map), 186

Python programming language

1. ?: operator in, 18

2. arrays in, 40, 46

3. closures in, 175

4. loops in, 23, 42

5. modules in, 86

Queue class, 187

r method (String), 124, 126

Random object, 9

RandomAccess interface (Java), 185

Range class, 6, 13, 194, 333

1. immutable, 187

2. traversing, 24

raw prefix, in formatted strings, 22

raw string syntax, 124

readXxx methods (scala.io.StdIn), 23, 119

ready method

1. of Await, 248

2. of Future trait, 249

recover, recoverWith methods (Future trait), 253–254

recursions, 186

1. for lists, 188

2. tail, 237

reduce method

1. of Iterable, 193

2. of Iterator, 202

reduceLeft method, 174

1. of Future object, 256

2. of Iterable, 193, 197

3. of Iterator, 202

reduceRight method

1. of Iterable, 193, 198

2. of Iterator, 202

reference types

1. == operator for, 110

2. assigning null to, 108

reflective calls, 282

Regex class, 124–126

1. findXxxIn methods, 124

2. replaceXrdn methods, 125, 225

regular expressions, 124–126

1. for extractors, 216

2. grouping, 126

3. raw string syntax in, 124

remove method (Map), 186

REPL (read-eval-print loop), 3–4

1. autocompletion in, 247

2. defining companion objects in, 79

3. displaying () value in, 19

4. nearsightedness of, 19

5. pasted code in, 20

6. types in, 170

replace method (Map), 186

replaceXxxIn methods (Regex), 125, 225

result method

1. of Await, 248

2. of Future trait, 249

3. with TailRec object, 237

return keyword, 28, 179

reverse method

1. of Iterator, 202

2. of Seq, 195

rich interfaces, 133

RichChar class, 6

RichDouble class, 6, 13

RichInt class, 6, 13, 24, 187

_root_ prefix, in package names, 88

Ruby programming language

1. closures in, 175

2. duck typing in, 283

s prefix, in formatted strings, 22

scala package, always imported, 87, 92, 121, 186

Scala programming language

1. embedded languages in, 149

2. interoperating with shell programs, 122

3. interpreter of, 1–4

4. methods vs. functions in, 27

5. strongly typed, 159

6. translating to JavaScript, 10

scala. prefix, in package names, 9, 92

scala.collection package, 205

scala.collection.concurrent package, 186

scala.collection.immutable package, 185

scala.collection.mutable package, 185

scala.compiletime package, 64

1. codeOf function, 324–325, 336

2. constValueXxx methods, 329

3. erasedValue method, 325, 330

4. error method, 325

5. summonXxx methods, 329, 335

scala.compiletime.ops.any package, 323

scala.compiletime.ops.int package, 323

Scala.js project, 10

scala.language.adhocExtensions object, 104

scala.language.implicitConversions class, 307

scala.language.strictEquality object, 110

scala.math package, 8, 13

scala.sys.process package, 122

scala.util package, 9

scalac program. See compiler

Scaladoc tool, 6, 11–14, 45–46

scanLeft method (ScanLeft), 200

Scanner class (Java), 59, 119

scanRight method (ScanLeft), 200

sealed classes, 330–331

sealed keyword, 104, 222

segmentLength method

1. of Iterator, 202

2. of Seq, 195

Selectable trait, 162–163, 282

selectDynamic method

1. of Dynamic, 160

2. of DynamicProps, 161

3. of Selectable, 162

selectors

1. dynamic, 159–162

2. for imports, 91

3. typesafe, 162–163

self types, 143–144

Seq trait, 30, 45, 184–187

1. methods of, 195

Seq[Char] class, 13

sequences, 13

1. adding elements of, 192

2. as function parameters, 30

3. comparing, 177

4. extracting values from, 157

5. filtering, 174

6. integer, 187

7. mutable/immutable, 187–188

8. of characters, 13

9. removing elements of, 192

10. reversing, 195

sorting, 174, 195

1. with fast random access, 187

Serializable trait, 121

serialization, 121, 234

@SerialVersionUID annotation, 121, 234

Set trait, 184

1. immutable, 186

sets, 189–190

1. difference, intersection, union of, 190–191

2. elements of, 189–192

@setter annotation, 240

setXxx methods, 66, 234

shadowing rule, 25

shell scripts, 122–124

Short type, 5

1. reading, 23

@showAsInfix annotation, 264

Singleton class, 284

singleton objects, 8–9, 78, 286

1. case objects for, 219

singleton types, 284–286

1. inference of, 323

sleep method (Thread), 246, 325

slice method

1. of Iterable, 194

2. of Iterator, 202

sliding method

1. of Iterable, 194, 201

2. of Iterator, 202

Some class, 56–57, 219, 222

sortBy method

1. of Iterator, 202

2. of Seq, 195

sorted method

1. of ArrayBuffer, 44

2. of Iterator, 202

3. of Seq, 195

4. of StringOps, 8, 14

sorted sets, 190

SortedMap trait, 55, 184

SortedSet trait, 184

sortInPlace method (Array), 44

sortWith method, 174

1. of ArrayBuffer, 44

2. of Iterator, 202

3. of Seq, 195

source files, 89

Source object, 118–120

1. close method, 118

2. fromString, fromURL methods, 120

3. getLines method, 118, 203

4. mkString method, 118–119

5. toArray, toBuffer methods, 118

span method

1. of Iterable, 193

2. of Iterator, 202

splitAt method

1. of Iterable, 193

2. of Iterator, 202

sqrt method (scala.math), 8

src.zip file (JDK), 226

Stack class, 187

stack overflow, 237

standard input, 120

start method, 125

startsWith method

1. of Iterator, 202

2. of Seq, 195

statements

1. indentation in, 21

2. line breaks in, 20

3. terminating, 20

StaticAnnotation trait, 239

stdin method, 120

StdIn object, 23, 119

strictEquality object, 110

String class, 124, 126

1. matches method, 338

2. substring method, 27

String class (Java), 6, 40

string interpolation, 22

StringBuilder class, append method, 58

StringOps class, 6, 13, 58

1. apply method, 9

2. concat method, 13

3. sorted method, 8, 14

strings, 6

1. characters in:

   1. common, 6

   2. concatenating, 13

   3. uppercase, 13

2. classes for, 13

3. converting:

   1. from any objects, 6

   2. to numbers, 10, 119

   3. to ProcessBuilder objects, 122

4. formatted, 22

5. sorting, 8

6. traversing, 25

structural types, 162, 281–283

subclasses

1. anonymous, 101

2. concrete, 102

3. equality in, 109

4. implementing abstract methods in, 131

5. mixing traits into, 143–144

subsetOf method (BitSet), 190

substring method (String), 27

Success class, 249

success method (Promise), 257

successful method (Future object), 256

sum method

1. of ArrayBuffer, 44

2. of Iterable, 193

3. of Iterator, 202

summonXxx methods (scala.compiletime), 329, 335

super keyword, 99, 135

super keyword (Java), 101

superclasses, 140–141

1. abstract fields in, 102

2. constructing, 100–101

3. extending, 142

4. methods of:

   1. abstract, 102

   2. clashing with subclass methods, 98

   3. overriding, 103

5. no multiple inheritance of, 130, 132, 137

6. of traits, 141

7. sealed, 222

supertypes, 18, 108, 266

Swing toolkit, 145–146

switch statement, 19, 210

synchronized method (AnyRef), 107

synchronous computations, 257

tab completion, 2

tail method

1. of Iterable, 193

2. of lists, 188–189

TailCalls, TailRec objects, 237

@tailrec annotation, 237

take, takeWhile methods

1. of Iterable, 193

2. of Iterator, 202

takeRight method (Iterable), 194

@targetName annotation, 151

tasks

1. assigning threads to, 246

2. blocking, 246

3. composing, 251–253

4. concurrent, 248–249, 251, 257

5. failing, 248, 252

6. running, 246–248

   1. in the future, 246–248

   2. on daemon thresds, 246

   3. one after another, 252

7. terminating, 247

8. throwing exceptions, 248

waiting, 248–249, 258

then keyword, 18

this keyword, 69, 72, 143–144, 285

Thread class (Java), stop method, 239

Thread class, sleep method, 246, 325

thread pool, 246

threads

1. assigning tasks to, 246

2. blocking, 249–250

3. daemon, 246

@threadUnsafe annotation, 238

throw expression, 34

Throwable class (Java), 33

@throws annotation, 235

to method

1. of collections, 185

2. of Iterable, 194

3. of Iterator, 202

4. of RichInt, 6, 24, 187

toArray method

1. of ArrayBuffer, 41

2. of Iterable, 194

3. of Iterator, 202

4. of Source, 118

toBuffer method

1. of Array, 41

2. of Iterable, 194

3. of Iterator, 202

4. of Source, 118

toChar method (RichInt), 6

toDouble method (RichInt), 6, 119

toIndexedSeq method

1. of Iterable, 194

2. of Iterator, 202

toInt method (RichInt), 6, 119

toIterable, toList methods

1. of Iterable, 194

2. of Iterator, 202

toMap method

1. for tuples, 59

2. of collections, 185

3. of Iterable, 194

4. of Iterator, 202

toScala method, 205

toSeq, toSet methods

1. of collections, 185

2. of Iterable, 194

3. of Iterator, 202

toString method

1. from Java, 45

2. of case classes, 219

3. of enumerations, 82

4. of RichInt, 6

toVector method

1. of Iterable, 194

2. of Iterator, 202

trait keyword, 131

traits, 131–144

1. abstract types in, 286

2. adding to objects, 133

3. construction order of, 135–136

4. constructors for, 138–140

5. extending, 79, 286

   1. classes, 140–141

   2. superclass, 142

6. extension methods in, 304

7. fields in:

   1. abstract, 137

   2. concrete, 136–137

8. for collections, 184–185

9. for rich interfaces, 133

10. implementing, 131, 267

11. initializing, 140

12. layered, 134–135

13. methods of, 132–135, 141–143

    1. overriding, 135–136

    2. unimplemented, 131

14. mixing into classes, 143–144

15. superclasses of, 141

16. transparent, 143

17. type parameters in, 264

18. universal, 112

19. vs. Java interfaces, 129–132, 141–143

20. vs. structural types, 282

21. with a self type, 143–144

trampolining, 237

transform, transformWith methods (Future trait), 254

@transient annotation, 235

transparent keyword, 143

traverse method (Future object), 255

Try class, 35, 249

1. flatMap method, 253

2. get method, 249

3. isFailure method, 249

4. isSuccess method, 249

5. map method, 253

try statement, 34–35, 225