#parser #operations #basic #expression-parser #arithmetic #rust-based #kucherenko

bin+lib operations_parser_kucherenko

A Rust-based parser for basic math operations with function support

2 releases

0.1.1 Nov 13, 2024
0.1.0 Nov 13, 2024

#647 in Math

Download history 217/week @ 2024-11-11

217 downloads per month

MIT license

9KB
85 lines

math_operations_parser_kucherenko

Math Operations Parser is a Rust-based library that parses and evaluates arithmetic expressions.

Features

  • Supports basic arithmetic operators: +, -, *, /, and ^
  • Handles function calls like sqrt(16) and sin(pi)
  • Can parse complex, nested expressions like 3 + sqrt(16) * (2^3)

Technical Overview

This parser uses the Pest grammar and parses expressions in multiple stages:

  1. Expression: The top-level rule.
  2. Sum: Handles addition and subtraction.
  3. Product: Handles multiplication and division.
  4. Power: Handles exponentiation.
  5. Function Call: Parses functions with expressions as arguments.

Usage

To use the parser, run the following command in the terminal:

cargo run -- parse <file>

To get available commands, just type in the commang:

cargo run -- help

For parsing an expression right from the command run:

cargo run -- "3 + sqrt(16)"

To get credits use:

cargo run -- credits

Grammar Structure

The parser uses a PEG-based grammar defined in grammar.pest. Below are the rules that govern expression parsing.

  • expression: Parses the entire arithmetic expression, starting with sum.
  • sum: Handles addition and subtraction.
  • product: Handles multiplication and division.
  • power: Handles exponentiation with ^.
  • unary: Handles unary operators (+ and -).
  • primary: Recognizes numbers, function calls, and grouped expressions (parentheses).
  • function_call: Matches function names followed by an argument in parentheses.
  • ident: Matches alphabetic characters used for function names or constants.

Full Grammar

WHITESPACE = _{ " " | "\t" }
expression = _{ sum }
sum = { product ~ (add_op ~ product)* }
product = { power ~ (mul_op ~ power)* }
power = { unary ~ (exp_op ~ unary)* }
unary = { unary_op? ~ primary }
primary = { number | function_call | "(" ~ expression ~ ")" }
number = @{ "-"? ~ ASCII_DIGIT+ ~ ("." ~ ASCII_DIGIT+)? }
add_op = { "+" | "-" }
mul_op = { "*" | "/" }
exp_op = { "^" }
unary_op = { "+" | "-" }
function_call = { ident ~ "(" ~ expression ~ ")" }
ident = @{ ASCII_ALPHA+ }
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Dependencies

~2.2–3MB
~59K SLoC