1. A semantic analyser strips out the comments and white spaces from input source program. 2. Semantic analysis involves verifying if the input source forms a legal set of instructions in accordance...

1. A semantic analyser strips out the comments and white spaces from input source program.

2. Semantic analysis involves verifying if the input source forms a legal set of instructions in accordance with the language rules.

3. A semantic analyser checks if all the variables are declared before use.

4. A semantic analyser checks if the operators are used on compatible operands.

5. What is a syntax-directed defi nition? What are its main characteristics? Illustrate with an example.