KTU CSE Btech Seventh Semester Complier Programing

 syntax tree. Certainly, I can help you with that. To convert BNF rules into YACC form and generate an abstract syntax tree (AST), let's consider a simple arithmetic expression grammar. Here's the BNF grammar for reference: ``` <expr> ::= <term> '+' <expr>          | <term> '-' <expr>          | <term> <term> ::= <factor> '*' <term>          | <factor> '/' <term>          | <factor> <factor> ::= '(' <expr> ')'           | <number> ``` Now, let's convert these BNF rules into YACC form and include code to generate an abstract syntax tree. The abstract syntax tree can be represented using a struct in C. ```yacc %{ #include <stdio.h> #include <stdlib.h> // Define the structure for the abstract syntax tree nodes typedef struct ASTNode {     char operatio...

Implementing a calculator using LEX and YACC involves defining the lexical rules using LEX and the grammar rules using YACC to parse and evaluate arithmetic expressions. Let's go through each line of code step by step. **Lexer (Lexical Analyzer using LEX)** Here's the code for the Lex part of the calculator: ```lex %{ #include "y.tab.h" %} %% [0-9]+      { yylval = atoi(yytext); return NUM; } [-+\*/\(\)] { return yytext[0]; } [ \t\n]     ; /* Ignore whitespace */ %% ``` Explanation of the Lex code: 1. `%{ ... %}`: This section allows including C code within the Lex file. Here, we include the "y.tab.h" header file that will be generated by YACC, containing token definitions. 2. `%%`: This double percentage sign separates the Lex rules from the C code. 3. `[0-9]+`: This rule matches a sequence of digits (a number) and converts it to an integer using `atoi()`. The `yylval` variable is used to pass the value to YACC, and `NUM` is returned as the token. 4. `[-+\*...