keithpitsui/paversparsec

Dependencies

This framework depends on PaversFRP and PaversSugar.

Example

That is an example from Parsec.

1. The following example use Xcode 10 as build environment. Given you have installed xcode 10

sudo xcode-select --switch /Applications/Xcode10-beta.app/Contents/Developer

1. Install PaversParsec with Swift package manager.

mkdir ParenParser
cd ParenParser
swift package init --type executable
vi Package.swift

1. Edit Package.swift to add dependencies for our ParenParser.

// swift-tools-version:4.2
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "ParenParser",
    dependencies: [
        // Dependencies declare other packages that this package depends on.
      .package(url: "https://github.com/KeithPiTsui/PaversFRP.git", from: "1.0.0"),
      .package(url: "https://github.com/KeithPiTsui/PaversParsec.git", from: "1.0.1"),
    ],
    targets: [
        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
        .target(
            name: "ParenParser",
            dependencies: ["PaversFRP", "PaversParsec"]),
    ]
)

1. We construct a parser for parsing parentheses matching by edit Sources/ParenParser/main.swift as following.

vi Sources/ParenParser/main.swift

import PaversParsec
import PaversFRP

func parenSet () -> ParserS<()> {
  let left: ParserS<()> = char("(").fmap(terminal)  ")"
  let mParen: LazyParserS<()> = fmap( many(parenSet), terminal)
  return left >>- mParen >>- right
}

let parens: LazyParserS<()> = (many(parenSet) >>- eof()) <|> eof()
let parser = parens()

let input1 = ParserStateS("()(())")
let result1 = parser.unParser(input1)
print(result1)
/**
ParserResult: Consumed
Parse OK
Got: ():()
*/

print("------------------")

let input = ParserStateS("(")
let result = parser.unParser(input)
print(result)
/**
ParserResult: Consumed
Parse Failed
Message:
{file: init, line: 1, column: 2}: 
msgUnexpected msgEndOfInput
msgExpecting )
*/

1. Build and execute.

swift build
./.build/x86_64-apple-macosx10.10/debug/ParenParser

The Parse OK results indicate successes: the parentheses matched. The Parse Failed result indicates a parse failure, and is detailed with an error message.

Use Cases

There are two applications of this framework.

One is for interpretion of JSON. PaversJSON

Another is for compiler of Kaleidoscope. SwiftParsecKaleidoscope

To-do

1. More use case for this library.

1. Make API documentation more descriptive and user-friendly.

1. Make PaversParsec production-ready.

Package Metadata

Repository: keithpitsui/paversparsec

Default branch: master

README: README.md