Section 1
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an interpreter
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Date created
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Cards (286)
Section 1
(50 cards)
an interpreter
translates the source program into a target program in machine code
tape storage is useful because it is
non-volatile and essentially unlimited in capacity
Static semantic checks
depend solely on the structure of the program and can be enforced at compile time
subtype analysis helps in determining whether heap allocation can be used instead of stack allocation
false
in dynamic scoping the bindings are
dependent on the calling sequences
the definition of regular expressions is often extended by string processing programming languages
true /(maybe it depends on the Chomsky language hierarchy)
imperative programming languages
focus on how the program is to accomplish its function and align better with the structure of the underlying hardware
C & C++ differentiate declarations and definitions
to support recursive and mutually-referential types
for an object to be used, it must be reachable by
existing in an active stack frame, being pointed to by a reachable object, being a global object
roles of semantic analyzer include
enforcing all dynamic rules
ada assigns a ___________ to every numeric variable and _____________
specific type //// requires the user to make explicit conversions
the distinctions between language categories, families, etc, are precise and clear cut
false
internal fragmentation of a heap is when the allocated block is to small
false
an optimization is said to be _____ if _______
unsafe //// it might lead to incorrect code in a program
commonly, unintended aliasing occurs because of
reference parameters
Backus-Naur Form (BNF) is
a formal notation for writing context free grammar
regular expressions are used to specify
token formats
comparing argument lists in function calls to that given in the function's declaration is an example of a
semantic check
the kleene plus operator extends regular expressions to the expressiveness of context-free grammar
false
an interpreter and a compiler are similar in structure
through the front end
a variable of an opaque type
may not be otherwise manipulated, may be declared, may be passed as an argument to the defining module
optimistic compilers insert dynamic checks to undo the effects of unsafe code when it goes wrong
true
context free grammars are more expressive than regular expressions (true/false)
true
the expressiveness of regular expressions may be expanded to that of context free grammars by adding
recursion
a regular expression is not allowed to
recurse, even indirectly
semantic rules may be either _______ or _______
static /// dynamic
the front end of the compiler is concerned with
determining what the program means
a context free grammar is used to specify a languages
parse structure
a sentence is a Sentential Form which has only
terminal symbols
a self hosting compiler
is written in its own language
the best programming language for any application is
the one you might learn something from, the one your colleagues are using, the one your boss tells you to use
the Kleene plus operator represents
one or more repetitions of a regular expression
modules into which name must be imported explicitly are called
closed scopes
a precondition failure indicates a problem with
a caller
which of the following is/are not know until runtime?
higher order functions construction, explicitly allocated object sizes, recursion limits
dynamic semantic checks
cannot be enforced until runtime
which one of the following best describes P-code ?
it is an intermediate code
C's dynamic semantic checking helps prevent inadvertent erros
No, C has no dynamic semantic checking at all
symbol table information may be made available at run time
to support symbolic debugging
which of the following is true about static scoping?
scope determination can be made by the compiler
there is always a one-to-one corresponding between names and objects
false
"design by contract" interface specifications are
formal, precise and verifiable
the null(or empty) string is a valid regular expression
true
IEEE 754 is a standard mandating
floating point operations
semantic analysis includes items that are not convenient to capture in the language's
context free grammar
why are stacks used to hold local variables
to make more efficient use of space and to support recursion
operator associativity and precedence are usually expressed in a language's
context free grammar
it is possible for a language to be both declarative and imperative
true
the back end of a compiler is concerned with
generating appropriate target code
a static analyzer is said to be precise if it allows the compiler to determine whether a program will never follow a rule
false
Section 2
(50 cards)
classes are better than modules when
one needs multiple instances
C's dynamic semantic checking helps prevent inadvertent errors
No, C has no dynamic semantic checking at all
floating point representation has how many representations for infinity ?
two, +infinity and -infinity
invariants, preconditions, and postcondtions are statements about the _______ of the program
correctness
in two's complement, a positive number's highest bit is
0
almost all modern machine at the macro level are
are a collection of devices connected to a bus
external fragmentation of a heap is when an allocation request is combines with another request for increased efficiency (true/flase)
false
a machines architecture is the _______ of the ______ of the machine in the abstract
formal specification //// capabilities and operation
two forms of iteration are
enumeration controlled and logically controlled
most operators are
left-associative, binding form left-to-right
the referencing environment
the set if active bindings
semantic analysis can require the presence of a return statement in a function easily
true
an optimization is said to be ________ if ________
speculative //// it usually improves performance but may degrade in some cases
the most important device in a machine's macro architecture is its
processor
static and precise type checking ensure that a variable will always be used in a type safe manner
true
a scope hole occurs for a name when
its binding is overriden by another declaration
why are central reference tables preferred to association lists
a lookup is fast because each slot is a linked list with the most recent binding in front
the difference between modules and classes is that
classes have inheritance and dynamic method dispatch and modules don't
any recursion can be rewritten as iteration
true
in four buts, the two's complement value 1000 represents
minus eight
(*(+12)3) is an example of
cambridge polish notation
big-endian and little-endian are different
orders for storing multiple-byte values in memory
a side effect can cause
the evaluation of the same expression to possible have a different result
recently processor speeds have _______ because of _______
plateaued ///// difficulties in dissipating heat
the use of an uninitialized variable
can always be detected, though it might be inefficient to do so
in four buts, the two's complement representation for -1 is
1111
semantic analysis includes items that cannot be covered by the language's
context free grammar
an association list is
a list of key, value pairs a list of linked list a linked list
a static analyzer is said to be precise if it allows the compiler to determine whether a program will never follow a rule (true/false)
false
there are many many machine architectures in general use
false
bindings may be made at
runtime, compile time, load time
identifying an array index out of bounds error is generally an example of a _______ check
dynamic semantic
which of the following is/are not known until runtime
recursion limits, explicitly allocated object sizes, higher-order functions constructions
recently processor speeds have _______ because of ______
plateaued //// difficulties in dissipating heat
an implementation of a machine's architecture is
how to architecture is realized as a specific machine
various kinds of control flow include
recursion, concurrency and procedural abstraction
fortran's assigned and computed goto statements
were more useful early on because fortran had no better constructs
syntax concerns the ______ of a program while the semantics concern its _______
form //// meaning
polymorphism allows
a single subroutine to accept arguments of multiple types
python provides _________ integer options
essentially infinite precision
Generally only ______ have to care about machine language
compilers (and interpreters)
compilers try to keep as much as possible in registers because
registers are much faster than other types of memory
lisp uses
cambridge polish notation
tail recursion can be converted into
iteration
short-circuit operators
have a defined evaluation order and may leave operands unevaluated
C & C++ differentiate declarations and definitions
to support recursive and mutually referential types
conservative compilers insert dynamic checks to undo the effects of unsafe code when it goes wrong
false
any bits retrieved form memory may be decoded as a legal instruction
false
operators can be
infix, prefix, or postfix
a compiler might generate different machine code for different implementations of the same architecture
true
Section 3
(50 cards)
The C++ using statement can be dangerous because
it can be misused accidentally to make more names visible than desired
in two complements, the four representation of zero is
0000
semantic analysis can require the presence of a return statement in function easily
true
creating the fortran compiler took about ______ because ______
18 staff years //// ti was the first compiler written
the best reason to study programming languages is
to get some background on how to understand all programming languages
java's dynamic semantic checking helps catch malicious errors
yes, that was a prime goal in the design of the language
values stored in memory have no particular
format or type, only a size
lexical analysis converts _____ into _____
characters //// tokens
in java, can a name be used before it is declared?
Yes, for standard package names in the global namespace
assignment operators are generally
right-associative, binding form right to left
which one of the following is not an example of a static semantic check?
pointers are never dereferenced unless they are refer to a valid object
the kleene star operator represents
zero or more repetitions of a regular expression
floating point numbers are represented in
a sign, an exponent, and a significant
it is generally possible to compile a program written in an interpreted language?
Yes, when assumptions are made and there is a fall-back process to handle violation
structured programming emphasized
top-down design and code modularization
fundamental data types include
signed and unsigned integers as well floating point numbers
a context-free grammar that permits multiple parse trees for the same string is
ambiguous
in selection
a choice is made of two or more statements or expression
most compiled language use
lexical scoping rules
dynamic method dispatch is when
a child class overrides a method in a parent and selection is made at compile time
Nested blocks
sometimes cause scope holes
which of the following is not an example of a dynamic semantic check?
a function with a non-void return type a value explicitly
a compiler's optimistic if it applies only optimization that are both safe and effective
false
in java, a primitive type are ______ and object types are ______
values //// references
lexical scoping
is defined in terms of the textual layout of the program and can be determined by the compiler
most network protocols express data in _____ form
big-endian
formal notation is used to describe a language's ______ and _______
syntax //// semantics
in two's complement representation, there
is one more negative number than postive numbers
numbers, identifiers, keywords, operators, and punctuation marks are different kinds of
tokens
syntactical analysis converts _______ into _______
tokens//// a parse tree
floating point numbers are generally
4 and 8 bytes in length
in logically controlled loops, the test must be
at the beginning of the loop, in the middle of the loop, at the end of the loop
compilation and interpretation are so different they cannot be used together
false
why are compilers able to detect more static semantic errors than interpreters?
compilers examine the entire code structure
various kings of control flow include
nondeterminacy, exception handling, and speculation
almost any well defined imperative algorithm can be expressed with only
sequencing, selection and iteration
right-most and left-most derivation from a context free grammar
may produce the same parse tree. It depends on the grammar
the kleene plue operator extends regular expressions to the expressiveness of context-free grammar
false
Names in programming language are a way to
reduce conceptual complexity by hiding irrelevant details and refer to program elements symbolically
a precondition failure indicates a problem with
a caller
historically, the ______ increased faster than the ______
processor's speed //// memory's speed
the C for statement
allows any changes the user wants to variables inside its body
when a loop exits, the value of the loop index variable is
[it depends on the language]
the set of strings defined by a regular expression is known as its
language
most languages have _____ modules
open scope
grammars are categorized into classes based on
the forms of production rules they are allowed to use
a machine's architecture is the _______ of the ________ of the machines in the abstract
formal specification//// capabilities and operations
what was the first high level programming language
fortran
a function call may be executed for
a side effect and its return value
Short-circuit operators
have a defined evaluation order and ma leave operands unevaluated
Section 4
(50 cards)
definite assignment requires that every variable can be shown to have
an assigned value on each path before each use
in two's complement representation, there
is one more negative number than positive numbers
in concurrency, multiple sections of code
are executed at the same time
python provides _____ integer operations
essentially infinite precision
the kleene plus operator extends regular expressions to the expressiveness of cfg
false
changing the value of the loop iteration variable inside the loop results in
undefined behavior
different implementations of the same architecture will all have identical machine languages (true/false)
false
well formed and nested parentheses, brackets are best recognized with
a context free grammar
semantic analysis is required for
enforcement of the rules for a valid program that go beyond the form of the program and determining information required for the generation of the output program
recursion is a central concept in
functional languages
association lists become inefficient when
programs get larger and more complex
a compiler
translates a source program into a target program and then goes away
all of the following are phases of a compile except
numerical analysis
examples of processor functional units include
instruction fetch, instruction decode and ALU operation
in an assignment, a variable name may appear
are and I-value and as an r-value
the von neumann object oriented and scripting language families are distinct and do not overlap
false
a binding to an object that is no longer alive is called a
dangling reference
the definition of a regular expressions is often extended by string processing programming languages
yes
static and precise type checking ensures that a variable will always be used in a type-safe manner (true/false)
true
to avoid ambiguity in derivation from a context-free grammar
the CFG must be defined so that in any derivation, only one parse tree can result
assignments have
an l-value and r-value
context free grammars can match counted lists easily
false
scope analysis help determine whether heap allocation can be used instead of stack allocation
false
all languages have
their own particular set of operators
most of the time the processor is
waiting for the user to do something and running the null job
among other things a regular expression can be
the alternation of two regular expressions and the empty string
in two's complement a negative number's highest bit is
1
the back end of the compiler is concerned with
generating appropriate target code
declarative programming languages
try to get away from irrelevant implementation details and focus on what the program is to do
lexical scoping ....
can be determined by the compiler and is most useful in dynamic binding languages
case or switch statements
are often clearer and cleaner than long if/then.... chains and can be implemented by the compiler in many ways
identifying an array index out of bounds error is generally an example of _____
dynamic semantic
an r-value indicates
the new value to store in an assignment
non-determinacy is when language features may be used
in any combination with consistent meaning
alias analysis can be used to determine when it is safe to
evaluate expressions out of order , cache values in registers, and allow access by concurrent threads
the order of operands and function call argument evaluation is
unspecified
what type of binding does C have?
static binding
roles of the semantic analyzer include
enforcing all dynamic rules
two models of assignment are
the value and the reference models
scientific notation includes
a sign, mantissas and an exponent
floating point representation has how many representations for 0?
two, +0 & -0
sequencing is central concept in
imperative languages
why are central reference table preferred to association list?
lookup is fast because each slot is a linked list with the most recent binding
orthogonality is when language features may be used
in any combination with consistent meaning
loop invariants are normally checked
before and after each loop iteration
JIT(just in time) compilation is
delaying compilation until the last possible moment
even in strict imperative languages, a compiler might reorder statements for optimization reasons
true
historically the _____ increased faster than the _____
processor's speed //// memory speed
resolution of overloaded names is carried out by the
semantic analyzer
in four buts the two's complement representation for -1 is
1111
Section 5
(50 cards)
many common processors are
either little or big endian
the cost of maintaining a system is usually
for more that the cost of developing it
in selectively open scope modules
names are automatically exported but require qualification
there is always a one-to-one correspondence between names and objects
false
recently, increases in machine performance have been because of
increases in the number of functional units/cores
heap storage is preferred to stack storage when
the size of the object may vary and the object may outlive the function that creates it
static and precise type checking ensure that a variable will always be used in a type-safe manner
true
all languages have
their own particular sets of operators
Static semantic rules are those that can be enforced at
compile time
dynamic type checking can never by completely safe
false
A compiler is conservative if it applies only optimizations that are both safe and effective
True
operators are
special, short names for certain functions
reference counting, mark/sweep, copying and generational are kinds of
garbage collection
The same bits in memory might form both legal integer and legal floating point numbers
True
assertions are
expected to be true when execution reaches them and used to check the correctness of a program
Example(s) of processor functional units includes
Registers and L1 Memory Cache
Semantic analysis is required for
Enforcement of the rules for a valid program that go beyond the form of the program. Determining information required for the generation of the output program.
Machine languages tend to be
very similar to each other
In two's compliment representation, there
is one more negative number than positive numbers
values have a type only in how
they are used
overloading is when
two or more different objects have the same name
The X86 Architecture is
little-endian
the three lifespans are
static, stack and heap
Preconditions and Postconditions
are expected to be true at the beggining and end of subroutines
A Post-condition failure indicates a problem with
A Callee
Integer numbers can be
unsigned signed 2,4,8, or 16 byte lengths two's compliment
As there are ________ machine architectures in general use, there are ___________ machine languages.
very few //////// very few
invariants
are expected to be true at all clean points of code
multiway assignment allows
exchanging two variables without using tempopry
a static analyzer is said to be precise if it allows the compiler to determine whether a program will always follow a rule
true
A c\c++ double usually has about how many decimal digits of precision?
about 16
Roles of the semantic analyzer includes
Enforcing all parsing rules
Java has what level of dynamic semantic checking?
High
escape analysis helps in determining whether heap allocation can be used instead of stack allocation
false
In four bits, the two's compliment value 1000 represents what integer?
-8
a processor is able to determine the type of data in memory by examining it
false
the fastest access memory available to the processor is
registers
a function's local variable must always be allocated on the stack
no, not necessarily depending on the language
A machine's macro architecture is
How it is structured as a collection of discrete units
In two's compliment the negation of a number is formed by
inverting the bits adding one and ignoring any overflow
An Invariant failure indicates a problem with
The encompassed code
an bits retrieved from memory may be decoded as a legal instruction
false
floating point operations are generally executed in
hardware
Semantic Analysis can match counted list easily
True
In four bits, the two's compliment representation for -1 is?
1111
once a binding is created between a name and an object , it persists until both the name and the object are destroyed (true/false)
false
forward reference is
a reference to a name that has not yet been declared
programmers generally can distinguish _______ at the functional level
registers from main memory from peripherals
All patterns of bits represent a legal floating point values
True
the semantic analyzer annotates the _____ with any information needed to _____
parse tree //// generate dynamic semantic checks
Section 6
(36 cards)