Concepts of Programming Languages

794 Index

Tuples, 280–281
Turing machines, 678
Turner, David, 52
twos complement, 247
Two-way selection statements
clause forms in, 350–351
control expressions for, 350
design issues for, 350
nesting selectors in, 351–354
selector expressions in, 354
type
in Ada enumeration types, 258
in Ada equivalence, 306–307
in Ada union types, 286, 289
in F#, 287
in ML, 281
Type, defined, 209
Type bindings
dynamic, 212–214
introduction to, 210
static, 211–212
Type checking
introduction to, 15
overview of, 302–303
parameters in, 408–410
Type conversions, 329–332
type enumeration type, 257, 261
Type equivalence, 304–308
Type errors, 303
Type inference, 211
typedef, 308

U
Unambiguous grammars, 123–126
Unary assignment data types,
338–339
Unary operators, 319
Unchecked exceptions, 650
Unconditional branch statements,
375–376
undef, 145–147
undefined, 264
Underflow, 332
Ungar, David, 548
Unicode, 249

Unification, 733, 759

Uninstantiated variables, 737

union, 285, 308

Union types

in Ada, 285–287

design issues for, 285

discriminated vs. free unions

in, 285

evaluation of, 288

in F#, 287–288

implementation of, 289

introduction to, 284

Unit-level concurrency. see

subprogram-level

UNIVAC, 40–41

UNIVAC Scientific Exchange

(USE), 53

University of Aix-Marseille, 79,

736

University of Edinburgh, 79, 736

University of Utah, 85

UNIX

programming environment of,

31

readability of, 13

systems software for, 6–7

Unlimited extent, 431

unsafe, C#, 296

USE (UNIVAC Scientific

Exchange), 53

use clause, 484, 516

User-defined

abstract data types,

476–478

ordinal data types. see Ordinal

data types

overloaded data types, 430

User-located loop control mecha-

nisms, 370–371

using directive, 515

V

val statements, 341, 704–706

Value, 209

Value types, 290

var declarations, 211–212

Variables

addresses of, 208

defined, 245

names of, 208

names vs., 207–209

type of, 209

value of, 209

Variable-size cells, 301

VAX minicomputers, 10

VB (Visual BASIC), 13

VDL (Vienna Definition

Language), 142

Vector processors, 578

Vienna Definition Language

(VDL), 142

virtual method tables (vtables),

566–568

virtual reserved word,

545, 557

Visible variables, 218

Visual BASIC (VB), 13, 65–67

Visual languages, 22

Visual Studio, 22, 31

void, 11, 389–393

void * pointers, 295

vtables (virtual method tables),

566–568

W

wait semaphores, 586–590

Wall, Larry, 95

Weakest preconditions

in assignment statements,

150–152

in axiomatic semantics,

149–150

in logical pretest loops,

154–158

in sequences, 152–153

Web software, 7

Weinberger, Peter, 95

Well-definedness, 18

Wheeler, David J., 42

when clauses, 598–599