Question

Match the following:

(P)	Lexical analysis	(i)	Leftmost derivation
(Q)	Top down parsing	(ii)	Type checking
(R)	Semantic analysis	(iii)	Regular expressions
(S)	Runtime environments	(iv)	Activation records

1. P – i, Q – ii, R – iv, S - iii
2. P – iii, Q – i, R – ii, S - iv
3. P – ii, Q – iii, R – I, S - iv
4. P – iv, Q – I, R – ii, S - iii

Answer 1

Correct Answer - Option 2 : P – iii, Q – i, R – ii, S - iv

Lexical analysis: Lexical analysis is the first phase of a compiler. It takes the modified source code from language pre-processors that are written in the form of sentences.  Lexical analyser breaks these syntaxes into a series of tokens. Lexical analysis uses regular expression to recognize identifiers.

Top down parsing: Top down parsing technique parses the input by starts constructing a parse tree from the root node moving down to the leaf nodes. Top down parser uses the left most derivation to generate the string.

Semantic analysis: Semantic analysis is the task of ensuring that declarations and statements of a program are semantically correct. For this, it uses type casting.

Run time environments: Run time environment is a state of the target machine, which may include software libraries, environment variables etc. to provide services to the processes running in the system. Activation records of a function are loaded into stack at runtime.