https://github.com/janbaig/tdop-parser

A Top Down Operator Precedence Parser
https://github.com/janbaig/tdop-parser

parser pratt-parser

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A Top Down Operator Precedence Parser

• Host: GitHub
• URL: https://github.com/janbaig/tdop-parser
• Owner: JanBaig
• Created: 2022-12-11T18:50:43.000Z (almost 2 years ago)
• Default Branch: main
• Last Pushed: 2023-10-27T21:11:26.000Z (about 1 year ago)
• Last Synced: 2023-10-27T22:29:18.319Z (about 1 year ago)
• Topics: parser, pratt-parser
• Language: C++
• Homepage:
• Size: 71.3 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# TDOP-Parser

Top Down Operator Precedence (TDOP) parsing is a parsing technique introduced by Vaughan Pratt in a 1973 paper. 

The technique combines the best properties of recursive descent and operator precedence.

This program can successfully parse and evaluate a given expression in accordance to a predefined set of precedence rules.

## Example

In accordance to BEDMAS, the input expression `2 * 10 / 5 - 1 + 4` can be successfully parsed and evaluated. The following is the output: 

```

> 2 * 10 / 5 - 1 + 4

Precedence Parsing:

( ( 2 * ( 10 / 5 ) ) - ( 1 + 4 ) )

Interpreter results:

-1

Tree Structure:

Left: 10, Right: 5, Operator: /

Left: 2, Right: ( 10 / 5 ), Operator: *

Left: 1, Right: 4, Operator: +

Left: ( 2 * ( 10 / 5 ) ), Right: ( 1 + 4 ), Operator: -

```

## Precedence Table (BEDMAS) 

| Operator      | Precedence |

| ----------- | ----------- |

| `-`   | 0       |

| `+`   | 1        |

| `*`   | 2        |

| `/`   | 3        |

## Future Goals

- [x] Implement a Custom Lexer

- [x] Implement a Stack-based Interpreter

- [ ] Support for Unary & Ternary Operators

- [ ] Allow decimal values as input 

- [ ] Create User Interface