I don't think LALR/LL(k) implies automated refactoring is easy and anything else does not!!
Obviously non-context-free grammars are a problem, but a GLR or PEG grammar is still perfectly refactorable.
You forget that refactoring an intuitive grammar to LALR involves totally mangling that grammar and making it more difficult for everyone.
If the language is expressed as a GLR or PEG grammar then tool makers have it easier I reckon - easier to understand grammar.
The way to really ensure it's easy for everyone is for the compiler write to provide some abstract yet intuitive representation of the underlying grammar.
It really isn't an either/or, it's a case of both at once, I think!
I think you hit the nail on the head there. "Context-free" is more of a requirement than LALR or LL. The author clearly isn't a parser writer. I am, but I've yet to try a PEG grammar because ANTLR does such a great job.
But this doesn't change his point (or mine): languages should be created that are easy to write parsers for, so that its easier to write good tools.
And I think this applies to the grammar too: ANTLR's .g files are a good grammar language because its easy to write tools for - hence AntlrWorks.
I'm the author and i did write some parsers. However i'm more in the write-parser-by-hand camp and context-free is not so hard here. ANTLR needs strange hacks to parse Python with its whitespace indentation. A handwritten parser just needs some context within the lexer.
In my eyes a parser generator is the solution, if you want to trade efficiency for cross-language-portability. ANTLR is probably the best solution at this point, though the C backend is quite wierd.
I like to get shit working first, and then downcode if the PG does a horrible job. Nothing better than a hand-written anything, but I like the options of tools. Stange hacks for python supports your original argument I believe.
Obviously non-context-free grammars are a problem, but a GLR or PEG grammar is still perfectly refactorable.
You forget that refactoring an intuitive grammar to LALR involves totally mangling that grammar and making it more difficult for everyone.
If the language is expressed as a GLR or PEG grammar then tool makers have it easier I reckon - easier to understand grammar.
The way to really ensure it's easy for everyone is for the compiler write to provide some abstract yet intuitive representation of the underlying grammar.
It really isn't an either/or, it's a case of both at once, I think!