[swift-dev] [swift-users] Swift Package Manager and main.swift

[Natthan Leong]

Hi,

Isn't it odd to have both main.swift and Main.swift for a project?

Considering Swift 3 provides source breaking changes, can this be still worth an side effort to pursue with the compiler team as advised by Kostiantyn in the bug report? If so, how'd I approach them regarding this?

Isn't the Swift Package Manager a (new) tool in handling Swift code? Is this really the case where a minor change/addition to a convention is so difficult that it shouldn't be done? Can't Xcode support only either Main.swift or main.swift in the future?

The bug report is linked here
https://bugs.swift.org/browse/SR-1379

> On May 2, 2016, at 09:34, Jordan Rose <jordan_rose at apple.com> wrote:
> 
> [+swift-dev, bcc swift-users] I’d be fine with supporting “Main.swift”. The one downside is that it could change behavior for existing projects relying on “Main.swift” being a library file, and that might mean it’s not worth making a change.
> 
> Jordan
> 
> 
>> On May 1, 2016, at 23:34, Kostiantyn Koval via swift-users <swift-users at swift.org> wrote:
>> 
>> Hi there,
>> 
>> main is common used naming for executables that contains main function. It’s required by Swift compiler and Swift Package Manager can’t do anything about that.
>> If you create a simple command line tool in Xcode, it will create main.swift file. If you try to rename it, it will feil.
>> I think this is correct behaviour.
>> If you still think that Swift should support Main.swift with upper case letter, than it should be discussed with compiler team.
>> 
>> - Kostiantyn
>> 
>> > Hi there,
>> > 
>> > This is what happened as I was trying out the Swift Package Manager for another project similar to the one shown below:
>> > 
>> > ~ $ mkdir example
>> > ~ $ cd example/
>> > example $ touch Package.swift
>> > example $ mkdir Sources
>> > 
>> > example $ vi Sources/Example.swift
>> > example $ cat Sources/Example.swift
>> > func printOther() {
>> > print("other")
>> > }
>> > 
>> > example $ vi Sources/Main.swift
>> > example $ cat Sources/Main.swift
>> > print("Hello World")
>> > printOther()
>> > 
>> > 
>> > example $ swift build
>> > Compile Swift Module 'example' (2 sources)
>> > /PATH/example/Sources/Main.swift:1:1: error: expressions are not allowed at the top level
>> > print("Hello World")
>> > ^
>> > /PATH/example/Sources/Main.swift:2:1: error: expressions are not allowed at the top level
>> > printOther()
>> > ^
>> > /PATH/example/Sources/Main.swift:1:1: error: expressions are not allowed at the top level
>> > print("Hello World")
>> > ^
>> > /PATH/example/Sources/Main.swift:2:1: error: expressions are not allowed at the top level
>> > printOther()
>> > ^
>> > <unknown>:0: error: build had 1 command failures
>> > error: exit(1): /PATH-SWIFT/usr/bin/swift-build-tool -f /PATH/example/.build/debug.yaml
>> > 
>> > 
>> > example $ mv Sources/Main.swift Sources/main.swift
>> > example $ swift build
>> > Compile Swift Module 'example' (2 sources)
>> > Linking .build/debug/example
>> > example $ .build/debug/example
>> > Hello World
>> > other
>> > example $
>> > 
>> > 
>> > I had to renameMain.swifttomain.swift. Is there a design decision on why the filename for the main swift file has to be lowercase or is this a bug?
>> > 
>> > If it’s a design decision, why are directory names forsource files allowed to have variations likeSources,Source,srcandsrcsas statedhere(https://github.com/apple/swift-package-manager/blob/master/Documentation/SourceLayouts.md#other-rules)but not the main swift file?
>> > 
>> > I’d be ok if onlyMain.swiftandmain.swiftare allowed since other files in theSourcesdirectory are commonly UpperCamelCasedue to the Type naming conventions e.g.example-package-playingcard/Sources(https://github.com/apple/example-package-playingcard/tree/master/Sources).
>> > 
>> > Or maybe I’m just being pedantic?
>> > 
>> > p.s. evenPackage.swiftis capitalized and notpackage.swift
>> > 
>> > $ swift --version
>> > Swift version 3.0-dev (LLVM 752e1430fc, Clang 1e6cba3ce3, Swift 56052cfe61)
>> > Target: x86_64-unknown-linux-gnu
>> > 
>> > 
>> > 
>> > 
>> > 
>> _______________________________________________
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>> swift-users at swift.org
>> https://lists.swift.org/mailman/listinfo/swift-users
> 
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