Syntax

Question 1

syntax

Answer 1

the form or structure of the expressions, statements and program units (formal method to describe how to determine a statement’s set membership in a Language)

Question 2

semantics

Answer 2

the meaning of the expressions, statements, and program units

Question 3

grammar

Answer 3

formal description of a Language

Question 4

sentence

Answer 4

a string of characters over some alphabet

Question 5

language

Answer 5

a set of sentences (characterized by the set of all valid statements / strings in that language.
The cardinality of this set is potentially infinite)

Question 6

lexeme

Answer 6

lowest level syntactic unit of a language

Question 7

token

Answer 7

category of lexemes

Question 8

recognizers; generators

Answer 8

grammars can be formally utilized in two distinct ways: for ____ and for ___. (two approaches to describing syntax)

Question 9

Recognition device

Answer 9

___ device reads input strings over the alphabet of the language and decides whether the input strings belong to the language (i.e.syntax analysis part of a compiler)

Question 10

Generators

Answer 10

A device that generates sentences of a language (one can determine if the syntax of a particular sentence is syntactically correct by comparing it to the structure of the generator

Question 11

grammars

Answer 11

what is the formal language-generation mechanism commonly used to describe the syntax of programming languages

Question 12

Backus-Naur Form (BNF) is equivalent to

Answer 12

Context-Free Grammars

Question 13

Context Free Grammar syntax

Answer 13

Grammar = (Start symbol, set of Non-terminals, set of Terminals, set of Production Rules)

Question 14

define non-terminal symbols

Answer 14

abstractions are used to represent classes of syntactic structures; they act like syntactic variables (often enclosed in angle brackets <>)

Question 15

define terminal symbols

Answer 15

they are lexemes

Question 16

Each Production Rule has:
•a left-hand side (LHS), which is a ___ ___, and
•a right-hand side (RHS), which is a ___ of ___ and/or ___

Answer 16

single non-terminal; string of terminals and/or non-terminals

Question 17

define derivation (given a set of grammar rules know how to give derivation)

Answer 17

determines the order that nodes of a parse tree are built

repeated application of rules, starting with the start symbol and ending with a sentence with all terminal symbol

Question 18

define sentential form

Answer 18

every string of symbols in a derivation

Question 19

valid sentence

Answer 19

a sentential form that as only terminal symbols

Question 20

define leftmost derivation

Answer 20

derivation in which the leftmost nonterminal in each sentential form is the one that is expanded
(expand leftmost nonterminal first)

Question 21

define rightmost derivation

Answer 21

expand rightmost nonterminal first

Question 22

define parse tree

Answer 22

hierarchical representation of a derivation

Question 23

a grammar is ambiguous if and only if:

Answer 23

it generates a sentential form that has two or more distinct parse tree

Question 24

which language has grammar based on predicate logic

Answer 24

LOGLAN (logical languages, also include Lojban and Ceqli)

Question 25

how can we eliminate ambiguity?

Answer 25

if we use the parse tree to indicate precedence levels of the operators

Question 26

Be able to use recursive BNF rules to describe lists of arbitrary length means:

Answer 26

be able to describe the list of potential sentences in the language generated by a particular grammar

Question 27

Explain what deep syntax structure and surface syntax structure are

Answer 27

Sentences can be either passive or active and that difference lies in their surface structure. But their deep structure may be the same, for example NP+V+NP

Question 28

What is structural ambiguity?

Answer 28

Sentences that can be understood in more than one way.

Question 29

What are "recursive rules"?

Answer 29

Syntactic rules that can be applied more than once in generating a structure.

Question 30

Why Semantic roles

Answer 30

Some words may be more difficult to find the semantic meaning for than table horse etc. Words as warning, advice, threat. If we look at words as having roles in a sentence instead of containers of meaning this becomes easier.