Lab 11 - Grammar in ANTLR

This repository contains tasks related to grammar implementation using ANTLR.

About ANTLR

ANTLR (ANother Tool for Language Recognition) is a powerful parser generator that can be used for a wide range of language processing tasks, including building parsers, interpreters, compilers, and more. It facilitates the creation of grammar-based tools by generating parsers for input languages.

Installation

To set up ANTLR, follow these steps:

Download ANTLR:
- Download the ANTLR tool folder, named as antler in the repo.
Place ANTLR Folder:
- Once downloaded, extract the contents of the ANTLR folder to a location of your choice. For instance, you might place it in the D drive (D:\antlr).
Set CLASSPATH System Environment Variable:
- Create a new System Environment Variable named CLASSPATH.
- Set its value to include the ANTLR JAR file. For example, .;D:\antlr\antlr-4.13.1-complete.jar.
  - This value includes the current directory (.) and the path to the ANTLR JAR file.
Update Path System Variable:
- Edit the Path System Variable to include:
  - %CLASSPATH%
  - D:\antlr
These additions allow Java to locate ANTLR classes and resources necessary for executing ANTLR-related commands and programs.
Verify Installation:
- To verify that ANTLR is correctly installed, open a command prompt and type antlr or java org.antlr.v4.Tool. If the installation was successful, you'll see ANTLR's command-line help.

Tasks

Task 1: ANTLR Commands for Expr.g4

To execute Task 1 related to Expr.g4, follow these steps:

Navigate to the 'tour' directory:
```
cd tour
```
Generate the lexer and parser using ANTLR for Expr.g4:
```
antlr Expr.g4
```
Check the generated Java files for Expr:
```
dir Expr*.java
```
Compile the generated Java files for Expr:
```
javac Expr*.java
```
Run the program with the generated parser and a test input file t.expr:
```
grun Expr prog -gui t.expr
```

Task 2: Generating Parsers with ANTLR for LabeledExpr.g4

To generate parsers using ANTLR for LabeledExpr.g4, follow these steps:

Change directory to calc:
```
cd calc
```
Generate parser without listener and with visitor:
```
antlr -no-listener -visitor LabeledExpr.g4
```
Check generated Java files:
```
dir LabeledExpr*.java
```
Compile generated files with Calc.java:
```
javac Calc.java LabeledExpr*.java
```
Execute the program with a test input file t.expr:
```
java Calc t.expr
```

Follow these sequential commands to generate parsers using ANTLR for LabeledExpr.g4.