SwiftCalc

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SwiftCalc
schwa/SwiftCalc

SwiftCalc

A Swift package for parsing and evaluating mathematical expressions.

The parser supports the basic math operators, variables and functions (defined in Swift). Under the hood it uses the wonder Owl Parser Generator https://github.com/ianh/owl.

Basic support for syntax coloring is provided in an extension of AttributedString.

Usage

There are three main types in this package: Compiler which compiles an expression string into CompiledProgram and then Executor which evaluates the CompiledProgram. The Executor can be reused for multiple expressions.

import SwiftCalc

let variables: [String: Value] = [
    "pi": .number(.pi),
    "sin": .function(Math.sin),
]
let program = try Compiler().compile("sin(1) * 10 * pi")
program.dump()
let executor = Executor(variables: variables)
let result = try executor.execute(program)
guard case let .number(resultValue) = result else {
    fatalError()
}

Demo Screenshot

Alt text

Description

  • Swift Tools 5.5.0
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Dependencies

  • None
Last updated: Thu Dec 01 2022 12:56:31 GMT-0500 (GMT-05:00)