1.2 Compilers

Question 1

What is Lexical ?

Answer 1

Relating to words or the vocabulary of
a language.

Question 2

What is Syntax ?

Answer 2

The structure of words in a language.

Question 3

What is Lexical analysis ?

Answer 3

• Comments and white space removed.
• Variables added to symbol table.
• Reserved words tokenised (e.g.while)

Question 4

What is the Symbol Table ?

Answer 4

Each item in the code is given a number (token)…
that the compiler uses instead of the item’s name.

Question 5

What are the steps of running code ?

Answer 5

Lexical analysis
|
Syntax analysis
|
Code generation
|
Optimisation

Question 6

What is Syntax Analysis ?

Answer 6

• Code (now tokenised) is checked against the rules of the language.
• Errors reported as a list.
• Detail of data types added to symbol
  table.

Question 7

What is Code generation ?

Answer 7

The program is converted to machine
code.

Question 8

What is optimisation ?

Answer 8

The compiler looks for ways to reduce
the number of instructions.

Question 9

Why is it good to optimise ?

Answer 9

• Code may be able to use fewer instructions.
• Some code may be included but never run.
• Faster methods available.