pollen performance and folders

[jestarray]

Coming from little experience with web dev, pollen is great! I have a few questions: 1: What is causing pollen take some time to generate pages since js based tools do it instantaneously? 2: I'd like to separate my pages into folders but I'm not sure how to write a directory down in the .ptree which is located at the root. Does every folder need it's own .ptree file?

[mbutterick]

1. A comparatively more gluttonous (but also more powerful) evaluation model.

2. Subfolders can have their own pagetree files, but they’re not required. I suggest you work backward from how you want to build your project, and let that dictate where the pagetree files are. For instance, for Beautiful Racket, I have one pagetree at the top, but it dynamically collects pages from subdirectories too. (And it can do this because a pagetree source is a self-contained program, etc.)

[jestarray]

ahh. wait, so how would I grab the file of a subdirectory?

#lang pollen
--
 
burial.html
chess.html
sermon.html
./Chapter_1/Part1.html //relative and absolute paths don't work.

edit: ohh wait.. so I have to use (string->path) ? EDIT2: i dont know why i didnt seek to look in the module reference documentation lol. reading it now

[mbutterick]

See Nesting pagetrees for one approach.

[jestarray]

@mbutterick so how would i generate a table of contents? i'm unsure how to import index.ptree

[mbutterick]

If you want to import ALL the data, you can just (require "index.ptree") into the table of contents page. Every .ptree file, including index.ptree, exports a doc variable with the pagenodes in it.

You can also selectively call pagetree helper functions like children and pass index.ptree as the pagetree source.

[jestarray]

Got it! One more question(sorry, a little new to racket), how do I flatten out a nested list?

'((ul
   (li (a ((href "00-Intro/00-Overview.html")) "00-Intro/00-Overview.html"))
   (li (a ((href "00-Intro/01-Language.html")) "00-Intro/01-Language.html"))
   (li (a ((href "00-Intro/02-Boolean_Logic.html")) "00-Intro/02-Boolean_Logic.html"))
   (li (a ((href "00-Intro/03-Optimization.html")) "00-Intro/03-Optimization.html"))
   (li (a ((href "00-Intro/04-NAND_HDL.html")) "00-Intro/04-NAND_HDL.html"))
   (li (a ((href "00-Intro/05-Multibit_buses.html")) "00-Intro/05-Multibit_buses.html")))
  (ul
   (li (a ((href "01-ALU/01-BinaryNumbers.html")) "01-ALU/01-BinaryNumbers.html"))
   (li (a ((href "01-ALU/02-BinaryAddition.html")) "01-ALU/02-BinaryAddition.html"))
   (li (a ((href "01-ALU/03-ALU.html")) "01-ALU/03-ALU.html"))))

I've been doing (car l) and (car (cdr l)) and this isn't going to scale well..

[MichaelMMacLeod]

match from racket/match is a good tool for this:

(match '((a b) (c d) (e f))
  [(list (list first second) ...)
   second])
; ==> '(b d f)

See the docs on match https://docs.racket-lang.org/reference/match.html?q=match#%28form._%28%28lib._racket%2Fmatch..rkt%29._match%29%29 for more information

There's also flatten from racket/list https://docs.racket-lang.org/reference/pairs.html?q=flatten#%28def._%28%28lib._racket%2Flist..rkt%29._flatten%29%29, but match would probably work better for you here.

On Wed, Apr 15, 2020 at 7:22 PM jestarray notifications@github.com wrote:

Got it! One more question(sorry, a little new to racket), how do I flatten out a nested list?

'((ul (li (a ((href "00-Intro/00-Overview.html")) "00-Intro/00-Overview.html")) (li (a ((href "00-Intro/01-Language.html")) "00-Intro/01-Language.html")) (li (a ((href "00-Intro/02-Boolean_Logic.html")) "00-Intro/02-Boolean_Logic.html")) (li (a ((href "00-Intro/03-Optimization.html")) "00-Intro/03-Optimization.html")) (li (a ((href "00-Intro/04-NAND_HDL.html")) "00-Intro/04-NAND_HDL.html")) (li (a ((href "00-Intro/05-Multibit_buses.html")) "00-Intro/05-Multibit_buses.html"))) (ul (li (a ((href "01-ALU/01-BinaryNumbers.html")) "01-ALU/01-BinaryNumbers.html")) (li (a ((href "01-ALU/02-BinaryAddition.html")) "01-ALU/02-BinaryAddition.html")) (li (a ((href "01-ALU/03-ALU.html")) "01-ALU/03-ALU.html"))))

I've been doing (car l) and (car (cdr l)) and this isn't going to scale well..

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[mbutterick]

Also look at the functions in txexpr (included with Pollen) for when you’re dealing with X-expressions. For instance, if you wanted a flat list of the li elements from the above, you could do:

(append-map get-elements your-list)

[jestarray]

So every page I have has a <time>4/19/20</time> tag and I want to grab all of them and create a TOC with the dates next to the title of pages.

Doing (select 'time path) gives me:

make-directory: cannot make directory
  path: /usr/share/racket/pkgs/errortrace-lib/errortrace/compiled/drracket/
  system error: Permission denied; errno=13

Is this the correct way to grab dates from every page?

[mbutterick]

That should work, though the error doesn’t make sense — it seems to be a file-permissions error triggered by something DrRacket is doing, not by Pollen per se. (Try running the same file from racket on the command line to see if the error is different.)

You can also store a time value in the metas table and extract it that way (could be faster in certain circumstances).

[jestarray]

Same error... I'm calling it correctly right? (select 'time 'chapter1/test.html) , I also tried: (select 'time (build-path (current-directory) "chapter1" "test.html")) ? I do actually have write permissions on the drive.. (make-directory) works fine.

[sorawee]

I feel it's going to be a back and forth conversation with little information gain to help you debugging if we just keep doing this. Do you have a link to your project? Or can you provide us a minimal template file / pollen.rkt and the problematic source file?