2. Symbol Meaning
Predefined element
Fixed element
Path lines

3. ž Allowable Paths – follow the railroad from
left to right and follow only one path

4. ž Eg, letter, sentence, program, variable
name
Variable

5. ž Reserved words,(Cannot use these words
as variables (memory allocation) e.g.,
Dim, -+, 0, 1
Dim
As

6. ž Eg, A Boolean Constant
T
F

7. ž Eg, A word
Letter

8. ž Eg, a
number that can be either positive
or negative
Digit
_

10. Were created to make it easier to
represent syntax

11. Symbol Meaning
:: = Is defined as
| Indicates choice between elements
<> Non terminal symbol

12. BNF is a text based metalanguage that is
read right to left. This way, syntax can be
represented by text, rather than diagrams

13. ž Invented to avoid the disadvantages of
BNF.
ž Easier to read, and less issues with things
like repetition and optional elements

14. Symbol Meaning
= Is defined as
| Indicates choice between elements
<> Non terminal symbol
{} Encloses elements to be repeated
[] Encloses optional elements

15. BNF EBNF
ž ::= ž =
ž Boolean::=T|F ž Boolean=T|F

16. BNF EBNF
ž < > ž < >
ž <Digit>::-0|1|2| ž <Digit>=0|1|2|
ž <Letter>::-a|b|c ž <Letter>=a|b|c

17. BNF EBNF
ž Written as is ž Written as is
ž Dim ž Dim
ž If ž If
ž 0 ž 0
ž 1 ž 1
ž k ž k

18. BNF EBNF
ž Defined as | ž Defined as |
ž Boolen::-T|F ž Boolen=T|F

19. BNF EBNF
ž No
Optional ž [ ]
Elements, so each
option must be ž Integer=[-] {<digit>}
repeated
Integer::- - {<digit>} |
{<digit>}

20. BNF EBNF
ž No repetition ž Indicated by { }
ž Repetition through ž Word={Letter}
recursion ž Repeated zero or more
ž Recursion is repetition times
achieved through a ž If it needs to be repeated
process calling itself one or more times, it is
written as
ž Word=Letter{Letter}

21. Public
Dim Variable As Data Type
Privat
e

22. Single
Short
Boolean
Byte
Char
Date
Time
Decimal
Double
Int
Long

23. Upper Case
LowerCase
UpperCas
e
Digit

24. 0
9
8
7
6
5
4
3
2
1

25. ž Construct
an EBNF diagram to describe a
best practice, legal if statement.
ž Should follow the following structure:
ž If condition Then statements Else else
statements