Re: grammars and indentation of input

As so often it turned out that the reason my program did not work was elsewhere (in the grammar). My approach worked al along. It was instructive to look at the examples you guys mentioned. Thanks Theo

Re: Fwd: Re: grammars and indentation of input

Well put. The clearest description of Python's approach I've read, explained it as a lexer that tracked indentation level, and inserted appropriate tokens when it changed.

Re: Fwd: Re: grammars and indentation of input

Oh, a side point: there's some confusion introduced by the lack of a scanner/lexer in modern all-in-one-parsers. Python, for example, uses a scanner and so its grammar is nominally not context sensitive, but its scanner very much is (maintaining a stack of indentation exactly as OP was asking abou

Re: grammars and indentation of input

Hi, On 13.09.2016 18:55, Patrick R. Michaud wrote: > I don't have an example handy, but I can categorically say that > Perl 6 grammars are designed to support exactly this form of parsing. > It's almost exactly what I did in "pynie" -- a Python implementation > on top of Perl 6. The parsing was d

Re: grammars and indentation of input

I don't have an example handy, but I can categorically say that Perl 6 grammars are designed to support exactly this form of parsing. It's almost exactly what I did in "pynie" -- a Python implementation on top of Perl 6. The parsing was done using a Perl 6 grammar. If I remember correctly, Pynie

Re: Fwd: Re: grammars and indentation of input

Hostile or not, thanks for your informative reply.

Re: Fwd: Re: grammars and indentation of input

Thank you, very much. Yes, I'm disappointed, but I'd rather know.

Re: Fwd: Re: grammars and indentation of input

> > Having the minutia of the programmatic run-time state of the parse then > influence the parse itself, is at the heart of the perl5 phenomenon "only > Perl can parse perl" I don't mean to be hostile, but you're demonstrably wrong, here. (also it's "only perl can parse Perl" as in, only the "pe

Re: Fwd: Re: grammars and indentation of input

On Tue, Sep 13, 2016 at 10:35:01AM -0400, Bennett Todd wrote: > Having the minutia of the programmatic run-time state of the parse then > influence the parse itself, is at the heart of the perl5 phenomenon "only > Perl can parse perl", which I rather hope isn't going to be preserved in > perl6.

Re: Fwd: Re: grammars and indentation of input

Hi Bennett, There are many situations that require non-contextfree languages. Even though much of these could be solved in the AST-building step (called 'transduction' in my days) instead of the parsing step, that does not solve all cases. I am just wondering if and to what extent we can parse

Re: Fwd: Re: grammars and indentation of input

Having the minutia of the programmatic run-time state of the parse then influence the parse itself, is at the heart of the perl5 phenomenon "only Perl can parse perl", which I rather hope isn't going to be preserved in perl6.

Fwd: Re: grammars and indentation of input

Thanks Timo and Brian, both examples are educational. However, they have a common limitation in that they both perform their magic after a Match object has been created. I was trying to influence the parsing step itself. I am experimenting to find if I can influence the parsing process progr

Re: grammars and indentation of input

I don't see why optimization would frustrate this approach. You are doing the correct thing as far as I can tell, but with one exception. The current implementation (last I checked) was sometimes slow in binding values. You might need to force it between an assignment and passing a bound match as a

Re: grammars and indentation of input

I've also recently been experimenting with parsing an indent-based language -- specifically, a small subset of Slim () -- I push to a stack when I see a tag, and pop based on the depth of the indendation. Here's a working example: https://git.io/vig93 Brian

Re: grammars and indentation of input

I haven't read your code, but your question immediately made me think of this module: https://github.com/masak/text-indented Would be interested to hear if this helps you! - Timo

grammars and indentation of input

Hi all, I am beginning to appreciate the power of grammars and the Match class. This is truly a major asset within Perl6. I have a question on an edge case. I was hoping to use a grammar for an input that has meaningful indented blocks. I was trying something like this: token element { <.