Currently working on the error productions question in @munificentbob's 'Crafting Interpreters.'
Because I am a fool, I am doing it on the finished interpreter and not on the chapter-incremental one where the question is actually presented.
One thing I am learning is that...
Because I am a fool, I am doing it on the finished interpreter and not on the chapter-incremental one where the question is actually presented.
One thing I am learning is that...
@munificentbob ...error productions are a difficult thing to do in a partial way, particularly if you are replacing a very common error (in this case 'Expect expression,' the base error at the bottom of the Parser tree).
I traded throwing an exception there for returning a new expression type.
I traded throwing an exception there for returning a new expression type.
@munificentbob 18 tests, not including mine, expect an exception there.
I am resolving this by going to each test, figuring out what parse error it's supposed to be checking for, and adding an error production there, too.
Am I making this too hard? Is there an incremental way to do this?
I am resolving this by going to each test, figuring out what parse error it's supposed to be checking for, and adding an error production there, too.
Am I making this too hard? Is there an incremental way to do this?
@munificentbob Fun discovery: the AST Generator doesn't like it when you try to make an expression type that takes no constructor inputs, which I got around by having Expr.Nothing accept a string I don't use
So we've got
return new Expr.Nothing("Nothing, there's nothing here, nothing");
So we've got
return new Expr.Nothing("Nothing, there's nothing here, nothing");
UPDATE: the longer I work on these error productions, the more fermented my parse error messages become 
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