Compilers

LR Parser

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Advantage of incorporating the macro-processor into pass 1 is that _________
Many functions have to be implemented twice
Functions are combined not necessarily creating intermediate files as output from the macro-processor and input to the assembler
More flexibility is provided to the programmer in that he may use all the features of the assembler in conjunction with macros
All of the mentioned
Explanation:
A general-purpose macro processor or general purpose pre-processor is a macro designed primarily for string manipulation, macro definition.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
What is terminal table?
Contains all constants in the program
Is a permanent table of decision rules in the form of patterns for matching with the uniform symbol table to discover syntactic structure
Consist of a full or partial list of the token is as they appear in the program created by lexical analysis and used for syntax analysis and interpretation
Is a permanent table which lists all keywords and special symbols of the language in symbolic form
Explanation:
A permanent database that has entry for each terminal symbols such as arithmetic operators, keywords, punctuation characters such as ‘;’, ‘,’etc Fields: Name of the symbol.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Which of these is true about LR parsing?
Is most general non-backtracking shift-reduce parsing
It is still efficient
Is most general non-backtracking shift-reduce parsing & It is still efficient
None of the mentioned
Explanation:
LR parsers are a type of bottom-up parsers that efficiently handle deterministic context-free languages in guaranteed linear time.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
A system program that setup an executable program in main memory ready for execution is?
Assembler
Linker
Loader
Load and go
Explanation:
A loader is the part of an operating system that is responsible for loading programs and libraries. It is one of the essential stages in the process of starting a program, as it places programs into memory and prepares them for execution.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
When ß (in the LR(1) item A -> ß.a,a) is not empty, the look-head _________
Will be affecting
Does not have any affect
Shift will take place
Reduction will take place
Explanation:
There is no terminal before the non terminal beta.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Assembler is a program that _________
Puts programs into memory and executes them
Translates the assembly language into machine language
Writes in high level language and produces an object program
None of the mentioned
Explanation:
An assembler is a program that takes basic computer instructions and converts them into a pattern of bits that the computer’s processor can use to perform its basic operations.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The construction of the canonical collection of the sets of LR (1) items are similar to the construction of the canonical collection of the sets of LR (0) items. Which is an exception?
Closure and goto operations work a little bit different
Closure and goto operations work similarly
Closure and additive operations work a little bit different
Closure and associatively operations work a little bit different
Explanation:
Closure and goto do work differently in case of LR (0) and LR (1).
Question 8
Marks : +2 | -2
Pass Ratio : 100%
When ß is empty (A -> ß.,a), the reduction by A-> a is done by _________
If next symbol is a terminal
Only If the next input symbol is a
Only If the next input symbol is A
Only if the next input symbol is a
Explanation:
The next token is considered in this case it’s a.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
What is the similarity between LR, LALR and SLR?
Use same algorithm, but different parsing table
Same parsing table, but different algorithm
Their Parsing tables and algorithm are similar but uses top down approach
Both Parsing tables and algorithm are different
Explanation:
The common grounds of these 3 parser is the algorithm but parsing table is different.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
System program such as compiler are designed so that they are _________
Re-enterable
Non reusable
Serially usable
None of the mentioned
Explanation:
Re-enterable is the keyword for compiler being designed.