Lecture Note 6

Question 1

What is specification of programming

Answer 1

a programming language specification (or standard or definition) is a documentation artifact that defines a programming language so that users and implementors (language translators) can agree on what programs in that language mean.

Question 2

What are the main translator for programming language translations

Answer 2

The assembler
The compiler
The interpereter

Question 3

Describe syntactic analysis

Answer 3

The syntactic analyser(parser) costruct a derivation tree for the list

Question 4

Describe semantic analysis

Answer 4

The derivation tree is subjected to checks of the language’s various context-based constraints.

Question 5

Descirbe Code optimization

Answer 5

Optimizes the code obtained from the preceding phases

Question 6

Describe code generation

Answer 6

Generates the final object code

Question 7

What is an interpreter

Answer 7

An Interpreter is also a program that translates high-level source code into executable code.

Question 8

What are the two parts of language specification

Answer 8

The syntax of a programming language is the part of the language definition that says what programs look like; their form and structure.

The semantics of a programming language is the part of the language definition that says what programs do; their behavior and meaning.

Question 8

The syntax of a programming language is usually described using a combination of two components??

Answer 8

i. A regular expression describing its lexemes,

ii. A context-free grammar which describes how lexemes may be combined to form a syntactically correct program.

Question 8

What are forms of programming language specification

Answer 8

i. Formal Language Specification

ii) ii. A description of the behavior of a compiler (sometimes called “translator”) for the language (e.g., the C++ language and FORTRAN).

iii)A model implementation, sometimes written in the language being specified

Question 9

What is programming language translation

Answer 9

Programming language translation is the conversion of statements written in one language to statements in another language e.g converting assembly language to machine code.

Question 9

What is a compiler

Answer 9

A compiler translates a program written in one high level language, the source code into another language which is the object code.

Question 9

What is an assembler

Answer 9

The assembler translates mnemonic operation codes into machine code, and symbolic addresses into machine addresses

Question 9

What is documentation

Answer 9

Documentation is any communicable material that is used to describe, explain or instruct regarding some attributes of an object or system such as its parts, assembly, installation, maintenance and use.

Question 10

Compilers are organized into three stages:

Answer 10

A front end
An optimizers
A back end

Question 10

Object codes to source codes is done in two parts??

Answer 10

Analysis and synthesis

Question 10

Types of assembler

Answer 10

Load and Go Assembler: Load-and-go assembler generates their object code in memory for immediate execution

One-Pass Assemblers : One-Pass Assemblers generate their object code in memory for immediate execution just like loadand-go assemblers.

Two Pass Assemblers: Two pass assembler translate instructions by converting labels to addresses, generating values defined by BYTE and WORD, processing the directives not done in pass one and then writing the object code to output device

Question 10

Mention the three types of translator

Answer 10

assemblers, interpreters and Compilers

Question 11

What are ways in which programming semantics can be described

Answer 11

Natural language: Description by human natural language

Formal semantics: Description by mathematics

Reference implementation: Description by computer program

Test suites: Descriptoin by examples of programs and their expected behaviours

Question 12

Mention the two parts involved in interpretion and describe them

Answer 12

a parser and an evaluator

.The parser breaks the program into language components to form a parse tree.

The evaluator then uses the parse tree to execute the program.

Question 12

What is the job of each stages

Answer 12

The front end is responsible for understanding the program.

The optimizer improves the intermediate representation to increase the speed or reduce the size of the executable which is ultimately produced by the compiler.

The back end converts the optimized intermediate representation into the output language of the compiler.

Question 12

Phases of compilation

Answer 12

Lexical analysis:
Syntactic analysis
Semantic analysis
Code optimization
Code generation

Question 12

Describe lexical analysis

Answer 12

The aim of lexical analysis is to read the symbols (characters) forming the program sequentially from the input and to group these symbols into meaningful logical units, which we call tokens.

Question 13

Mention advantages of an interpreter

Answer 13

1. Good at locating errors in programs
2. Debugging is easier since the interpreter stops when it encounters an error.
3. If an error is deducted there is no need to retranslate the whole program

Question 14

Mention disadvantages of an interpreter

Answer 14

Disadvantages of an Interpreter
1. Rather slow
2. No object code is produced, so a translation has to be done every time the program is running.
3. For the program to run, the Interpreter must be present