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picoe / Eto.Parse

Recursive descent LL(k) parser for .NET with Fluent API, BNF, EBNF and Gold Grammars
MIT License
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Is there any reason why Name is not preserved when cloning a Parser #46

Closed olivr70 closed 3 years ago

olivr70 commented 3 years ago

Hello,

I just discovered Eto.Parse and I really enjoy it. Great piece of work.

I would like use it to build a library of reusable parsers which can be combined in multiple small grammars for scraping items in documents.

The problem is that when cloning a Parser, the names are lost and it does not properly fill the Matches property of the result

The following test fails

            var p = Eto.Parse.Terminals.Literal("hello");
            var helloNamed = p.Named("greetings");
            Assert.AreEqual("greetings", helloNamed.Name);
            var helloClone = helloNamed.Clone();
            Assert.AreEqual("greetings", helloClone.Name); // FAILS helloClone.Name is null

I just checked Parser copy constructor, and it does not set the name of the new instance to the one of the source.

Is there any reason for this, or can I make a Pull request ?

olivr70 commented 3 years ago

Just discovered that AddMatch property is not copied either in Parser copy constructor.

I connot see a reason why, and from a newcomer perspective I do not predict any negative impacts.

cwensley commented 3 years ago

The main reason is having two parsers with the same name in the same grammar is a conflict. It could very well copy the name, however as you can just overwrite it with the WithName() extension.

Thanks for the feedback! (and sorry for the late response)