Clojurians Log v2

hello everyone, is there a grammar for clojure source that i can use in instaparse?

or EDN would probably work in a pinch too

Not that I know of. Maybe this would help, you could port the ANTLR grammar into EBNF somehow http://stackoverflow.com/questions/3902813/is-there-a-language-spec-for-clojure

Although an EDN parser wouldn't be too hard to make from scratch. It's mostly balanced parens with various types of leafs or delimiters. The hard part is strings, handling all the \" stuff

And comments

yeah i was thinking that also, really i just need curly braces, because i only want to parse maps

but curlies can appear in strings

Maps with no lists / sets as keys or values?

yeah the map can contain anything, but i can presumably slurp that in and just look for the matching curly

If you get the string terminal right, Instaparse will be smart about closing parens even if parens appear within the string

how about indentation-based languages?

ehhhhhh

haha yeah

"You're thinking in the wrong mindset" http://imgur.com/gallery/M5wl14r

hahahaha excellent reference there

the project i'm working on is a generalized, abstract sort of markdown

it's designed to mix well with prose, so indentation based structure is a big win

So like, prose at the top level, important stuff indented?

# This is line 1 of a certain type of block.
  The block continues here because of the indentation.

* This could be a list item

  p With a paragraph in it
    that continues on multiple lines...and
    has a strange #(inline something or other
    delimited by hash-parens)#...

  ~~~{:foo "bar", :baz 123} tags can also have
    attributes parsed as EDN...

* here is the next list item

there we go

the parser will be a macro really

it will emit s-expressions

calling multimethods

so you can implement dispatches for any tags you like

so what # foo means is up to you

the indentation is crucial for making the thing general without special cases and hardcoded things

The reason "ehhhh" is the visceral response to indentation based langs in instaparse is because in CFGs it's difficult if not impossible to remember how many spaces / tabs you're looking for on each line.

So it's really only a problem if you have chunks within chunks that are indented even more.

yeah, and i want to support even more tricky things, like indentation plus extra whitespace at the front of the line

i have a naive handmade parser now to parse the blocks

it looks for tags that can start a block

then it looks for the "outdent"

so it doesn't look for a specific amount of indentation

Example?

it looks for a minimum amount of indentation, but you can use more

# This is all
  part of the
    same block
  and the next
  block
    doesnt
      start until the
  an "outdent" is seen

This is an outdent, so
the above block will 
have been ended.

however,

# This is not
  all part of the same
  # block because this
    tag creates a nested
    block

Hmm, what if you parse each block and then run the parser AGAIN on the text in the block to find subblocks?

hm

i think i could give up the leading extra spaces thing, too

and set indentation to some configurable fixed size

(my-parser text) => ([:block "This is not" "all part of the same" "# block because this" "   tag ..."])
(insta/transform *1 {:block (fn [& strs] (my-parser (str/join "\n" strs)))})

Except recursively smarter

interesting

I just thought of this, it might end up being impractical.

But that might be the way to do it.

i will play around with it and let you know how it works out

i can at least instaparse the inline stuff, if not the blocks

True

Anyway, now that I think about it, this trick may be applicable to any indentation-based language

it's also an interesting case because i need to parse "any character that isn't a tag"

like the text in between tags

i think i can use negative lookahead with regex like #"."

anyway thanks for the help! i'll let you know how it all works out

No problem, I'd love to hear how it goes