Menu_634641194757402500_CS6106 Compiler Design Lab Assignments

SEMESTER-VI

CS 6106

COMPILER DESIGN

LAB ASSIGNMENTS

DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

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B. I. T. MESRA

[Questions in bold are optional and carry higher credit] You are permitted to use any of the 3 programming languages – C, C++, Java – unless and until explicitly stated in the problem statement. Programming Assignments 1. Consider the following regular expressions: a) (0 + 1)* + 0*1*  b) (ab*c + (def) (def)+ + a*d+e)+ c) ((a + b)*(c + d)*) + + ab*c*d Write separate programs for each of the regular expressions mentioned above.

2. Design a Lexical analyzer for identifying identifying different types of token used in C language. [Note that the reserved reserved keywords such as if, else, class, struct etc must be reported reported as invalid identifiers. identifiers. C allows identifier identifier names to begin with underscore underscore character too. Further, Further, the real numbers can also also be -30 expressed in the form 1.75e-30 which is 1.75 x 10 . ] 3. Given a text-file which contains some regular expressions, with only one RE in each line of the file. Write a program which accepts a string from the user and reports which regular expression accepts that string. If no RE from the file accepts the string, then report that no RE is matched. 4*. Write a program which accepts a regular expression from the user and generates a regular grammar  which is equivalent to to the R.E. entered by user. The grammar grammar will be printed to a text file, file, with with only one  production rule in each line. Also, Also, make sure that all production production rules are displayed displayed in compact compact forms e.g. the production rules: S--> aB, S--> cd S--> PQ Should be written as S--> aB | cd | PQ And not as three different production production rules. Also, there should not be any repetition repetition of production rules. 5. Write a program to eliminate eliminate left recursion. recursion. 6. Write a program for Recursive Recursive Descent Calculator. Calculator. 7. Write a program that recognizes recognizes different different types of English words. 8. Consider the the following grammar: S --> ABC A--> abA | ab B--> b | BC C--> c | cC Following any suitable parsing technique(prefer top-down), design a parser which accepts a string and tells whether whether the string string is accepted by above grammar or not. [This grammar is not as simple as it appears to be. Try to check if the string abbcc is accepted or not. It is accepted, but improper logic of parsing can cause the program to get stuck or go into infinite loop !! The students are permitted to generate an equivalent grammar by removing ambiguities (if any) and  immediate left-recursion left-recursion from the given grammar.]

9. Write a program which reads a left-recursive regular grammar, and removes left recursion from the grammar.  For example: A possible input grammar is S--> Sa S-->a Its output after removal of left-recursion will be S--> aS S-->a [Extra credit will be given if the code is able to handle production rules of the type S--> Sa | a etc.] 10. Write a program which accepts a regular grammar with no left-recursion, and no null-production rules, and then it accepts a string and reports whether the string is accepted by the grammar or not. 11. Design a parser which accepts a mathematical expression (containing integers only). If the expression is valid, then evaluate the expression else report that the expression is invalid. [Note: Design first the Grammar and then implement using Shift-Reduce parsing technique. Your program should generate an output file clearly showing each step of parsing/evaluation of the intermediate subexpressions. ] [Extra credit will be given if the program can handle advanced operations such as exponentiation, squareroot, cube-root, logarithm etc] 12. Implement problem no. 2 using LEX , and problem no. 8 and 11 using YACC . 13*. Consider the following sample program written in a hypothetical language. BEGIN PRINT “HELLO” INTEGER A, B, C REAL D, E STRING X, Y A := 2 B := 4 C := 6 D := -3.56E-8 E := 4.567 X := “text1” Y := “hello there” PRINT “Values of integers are [A], [B], [C]” FOR I:= 1 TO 5 STEP +2 PRINT “[I]” PRINT “Strings are [X] and [Y]” END Output of the above hypothetical program is HELLO Values of integers are 2, 4, 6 1 3 5 Strings are text1 and hello there. Develop a grammar for this hypothetical language, and then write a compiler which works as per the following phases. The input is a program in the aforesaid hypothetical language. Filename has the extension as “.hyp” Phase 1: Lexical analysis – checks whether the syntax is correct or not. If correct, proceed to Phase 2, else report the exact line number where the syntax is incorrect, and stop then and there.

Phase 2: Generation of symbol table to handle the variables and their types etc. An output file called symtab.sym will be created which will contain the relevant data. This symbol table will be used while generating the intermediate code in next phase for detecting undeclared variables etc, and reporting linker  errors appropriately. Phase 3: Using the result of lexical analysis, the input file and the symtab.sym –   generate the intermediate code – in C++ or Java. The intermediate code will be generated in a file called _interm.c or   _interm.java as the case may be. As explained above, if any undeclared variables, or invalid values for  any variable are encountered, then generate a linker error containing the exact variable name, and line number, and stop immediately without generating any intermediate code. The intermediate code must be compiled and run by the appropriate compiler (cc or javac) without any errors. [This is a very open-ended problem. The more features of language taken into consideration, will be given more the marks. Also, check for cases of undeclared variables, assignment of integer value to STRING variables, assigning of real numbers to INTEGERS etc]

14. Develop a parser which accepts a string and reports whether it is a valid SQL query statement or  not. 15*. Develop an interpreter which understands the assembly language instructions for Intel-8085 microprocessor, and executes the instructions correctly. User should be able to see the values in all relevant “registers” (registers will be implemented through variables) at any time. A sample working of the interpreter is shown below input: output: input: output: input: output: input: output: input: output: input: output:

MVI A, 34H Valid statement. A = 0x34 = 52 MOV A Invalid statement. No source register specified INC A Valid statement. A = 0x35 = 53 MVI B, 10H Valid statement. B = 0x10 = 16 ADD A, B Valid statement. A = 0x45 = 69, B = 0x10 = 16 LXI H, 1234H Valid statement. Register pair HL. H = 0x12 = 18, L = 0x34 = 52