https://github.com/mgriebling/expressionparser

Swift expression parser and evaluator using a parser generated by Coco. Also produces a LaTeX translation of the text-based input expression.
https://github.com/mgriebling/expressionparser

ast coco compiler-compiler evaluator expression latex parser swift syntax-tree

Last synced: about 2 months ago
JSON representation

Swift expression parser and evaluator using a parser generated by Coco. Also produces a LaTeX translation of the text-based input expression.

• Host: GitHub
• URL: https://github.com/mgriebling/expressionparser
• Owner: mgriebling
• License: mit
• Created: 2024-09-05T15:41:21.000Z (4 months ago)
• Default Branch: main
• Last Pushed: 2024-10-16T12:01:46.000Z (3 months ago)
• Last Synced: 2024-11-12T11:02:55.395Z (about 2 months ago)
• Topics: ast, coco, compiler-compiler, evaluator, expression, latex, parser, swift, syntax-tree
• Language: Swift
• Homepage:
• Size: 43 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fmgriebling%2FExpressionParser%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/mgriebling/ExpressionParser)

[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fmgriebling%2FExpressionParser%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/mgriebling/ExpressionParser)

# ExpressionParser

The **ExpressionParser** package parses and evaluates mathematical expressions

and produces both a `LaTeX` translation and an evaluated result.

For example, the following:

```swift

let e = ExpressionParser("(-b+sqrt(b^2-4a*c))/2a")

Ident.addSymbol(("a", 1))

Ident.addSymbol(("b", -3))

Ident.addSymbol(("c", -4))

if let b = e.parse() {

    print(b)

}

```

produces an output of:

```

("\\frac{-{b}+\\sqrt{{b}^{2}-4{}{a}\\times{c}}}{2{}{a}}", 4.0)

```

where the `LaTeX` string gives the following typeset equation

$\frac{-{b}+\sqrt{{b}^{2}-4{}{a}\times{c}}}{2{}{a}}$

## Usage

In your project's `Package.swift` file add a dependency like

```

dependencies: [

    .package(url: "https://github.com/mgriebling/ExpressionParser.git", from: "0.1.0"),

]

```

## Theory

**ExpressionParser** contains two source files, `Parser.swift` and `Scanner.swift`.

They were produced by the Coco compiler [https://github.com/mgriebling/Coco]

translating an input ATG (Attributed Grammar) file (exp.atg) that describes the operations to be scanned

and parsed in a compact text format.  The `Coco` compiler generator also

requires some `.frame` files into which sections of code are inserted to

produce the final swift parser and scanner files.  An Abstract Syntax Tree

representation (AST) is built up using the `AST.swift` data type. This

tree is then evaluated to generate the `LaTeX` translation and evaluates

a result.  For more details about `Coco` refer to the 

https://ssw.jku.at/Research/Projects/Coco/ web site.