#LR Parser in C

Overview

This project implements a simple LR parser C. The parser is driven by external grammar rules, action tables, and goto tables. The main source file is lrParser.c, and it is supported by several additional source and header files:

• grammar.h
• string_queue.h, string_queue.c
• string_stack.h, string_stack.c
• tree.h, tree.c

These supporting files provide essential data structures used by the parser.

Setup Instructions

1. Set up a C compiler (e.g. GCC)
2. Clone or download the project files.
3. Open the project folder in your IDE (e.g. Visual Studio Code).
4. Set up your tasks.json and launch.json for build and debugging.

tasks.json

{
    "version": "2.0.0",
    "tasks": [
      {
        "label": "build LR Parser program",
        "type": "shell",
        "command": "gcc",
        "args": [
          "-g",
          "lrParser.c",
          "string_stack.c",
          "string_queue.c",
          "tree.c",
          "-o",
          "lrParser"
        ],
        "group": {
          "kind": "build",
          "isDefault": true
        },
        "problemMatcher": [
          "$gcc"
        ],
        "detail": "Build all files into lrParser"
      }
    ]
  }
  

Make sure all relevant source files are included in the build task.

launch.json

{
    "version": "0.2.0",
    "configurations": [
      {
        "name": "Debug lrParser",
        "type": "cppdbg",
        "request": "launch",
        "program": "${workspaceFolder}/lrParser",  // Path to the compiled binary
        "args": [],  // Add command-line arguments here if needed
        "stopAtEntry": false,
        "cwd": "${workspaceFolder}",
        "environment": [],
        "externalConsole": true,  // Set to true if you want an external console
        "MIMode": "lldb",  // Or "lldb" depending on your system and debugger
        "preLaunchTask": "build LR Parser program"  // This matches your task label
      }
    ]
  }
  

Ensure the preLaunchTask field matches the label in tasks.json.

Running the Parser

In lrParser.c, update the file paths for your grammar, action, goto, and input files:

char*** actionTable = readFile("PathToActionTable.txt", &aRows, &aCols);
char*** goToTable = readFile("PathToGotoTable.txt", &goRows, &goCols);
Grammar* grammarTable = readGrammar("PathToGrammar.txt");
Queue input = getInput("PathToinput.txt");
   

Replace the "PathTo..." strings with actual paths to your .txt files.

Sample inputs created by Beyza Eken are provided in the inputs folder

Execution

1. From a code editor:

To run the parser:

1. Build the project using the task: build LR Parser program.
2. Start debugging using the Debug lrParser configuration in your editor.

2. From a CLI

To run the parser:

1. Build the project from it’s root folder with the following command

gcc -g lrParser.c string_stack.c string_queue.c tree.c -o lrParser

2. Run the executable

MacOS X ./lrParser

Windows .\lrParser