Chapter 2 (Paradigm)

Question 1

What is a syntax?

Answer 1

Its a precise description of all its grammatically correct programs

Question 2

With what program was precise syntax used?

Answer 2

Algol 60

Question 3

Levels of syntax?

Answer 3

Lexical syntax
Concrete syntax
Abstract syntax

Question 4

What is a lexical syntax?

Answer 4

all the basic symbols of the language (names, values, operators)

Question 5

What is a concrete syntax?

Answer 5

rules for writing expressions, statements and programs.

Question 6

What is an abstract syntax?

Answer 6

Internal representation of the program, favoring content over form

Question 7

What is a metalanguage?

Answer 7

Its a language used to define other languages

Question 8

What is a grammar?

Answer 8

Its a metalanguage used to define the syntax of language

Question 9

What is a BNF? What does it do?

Answer 9

Backus-Naur Form
stylized version of a context-free grammar
First used to define syntax of Algol 60

Question 10

What is a parse tree?

Answer 10

Parse tree is a graphical representation of derivation.

Question 11

What does a parse tree do?

Answer 11

node of the tree corresponds to a step in derivation

each child of node represents a right-hand side of production

each leaf node represents a symbol of the derived string

Question 12

How can a grammar be defined?

Answer 12

With associativity and precedence

Question 13

When is grammar ambiguous?

Answer 13

When one of its strings has two or more different parse trees.

Question 14

What is a lexer?

Answer 14

Its the process of converting a sequence of characters into a sequence.
Input: characters
Output: tokens

Question 15

What is a parser?

Answer 15

Based on BNF/EBNF grammar.
Input: tokens
Output: parse tree.