This document discusses syntax analysis in programming languages. It defines syntax as the arrangement of words and symbols in a program to show their relationships. Syntax analysis determines if a program is valid based on the syntactic rules of the language. Common formal methods for describing syntax include grammars, parse trees, and syntax diagrams. Grammars provide mathematical rules for valid symbol strings, including terminal symbols, non-terminal symbols, and productions.

1. SYNTAX ANALYSIS

2. CONTENTS
o Syntax
o Syntax Terminology
o Syntatic element of the Language
o Syntax Analysis
o Formal Methods of Describing Syntax
Grammar
Parts of Grammars
Parse Tree
Syntax Diagram
1

3. Syntax
“The arrangement of words as elements in a sentence
to show their relationship” describes the sequence of
symbols that make up valid programs.
Form of expressions, statements and program units.
2

4. Syntax Terminology
 A sentence is a string of characters over some alphabet
 A language is a set of sentences
 A lexeme is the lowest level syntactic unit of a language
(e.g., *, sum, begin)
 A token is a category of lexemes (e.g., identifier)
3

5. Syntactic elements of the Language
 Keywords and reserved words – is an identifier used as
a fixed part of the syntax of a statement. It is a reserved
word if it may not be used as a programmer-chosen
identifier.
 Noise words – optional words that are inserted in a
statements to improved readability.
4

6. Syntactic elements of the Language
 Comments – important part of the documentation.
REM, /* */, or //
 Blank (spaces)
 Delimiters – a syntactic element used simply to mark
the beginning or end of some syntactic unit such as a
statement or expression. “begin”…”end”, or { }.
5

7. Syntactic Analysis
 Determines if the program being compiled is a valid
sentence in the syntactic model programming
language.
6

8. Formal Methods of Describing Syntax
 Grammars
 Parse Trees
 Syntax Diagrams
7

9. Grammars
 Formal definition of the syntax of a programming
language.
 Collection of rules that define, mathematically, which
strings of symbols are valid sentences.
8

10. Parts of Grammar
 Set of tokens/terminal symbols
 symbols that are atomic / non-divisible
 can be combined to form valid constructs in the
language
 Set of non-terminal symbols
 symbols used to represent intermediate definitions
within the language
 defined by productions
 syntactic classes or categories
9

11. Parse Tree
 Parse trees are trees level by symbols of a particular
context free grammar(CFG).
 Leaves : level by a terminal.
 Interior nodes: level by a variable.
 Root: must be level by the start symbol.
10

12. Thank you…
…

13. Any Queries???
…