◊(Local Yarn Code "Check-in [5256383c]")

@(require (for-label "../pollen.rkt"
                     "../dust.rkt"
                     racket/base
                     txexpr
                     sugar/coerce
                     pollen/tag
                     pollen/setup
                     pollen/pagetree
                     pollen/core))

@(define dust-eval (make-base-eval))
@(dust-eval '(require "dust.rkt"))

@title{@filepath{dust.rkt}}

@defmodule["dust.rkt" #:packages ()]

This is where I put constants and helper functions that are needed pretty much everywhere in the
project. In a simpler project these would go in @seclink["pollen-rkt"]{@filepath{pollen.rkt}} but
here I have other modules sitting “behind” that one in the @tt{require} chain.

@section{Constants}

@defthing[default-authorname string? #:value "Joel Dueck"]

Used as the default author name for @code{note}s, and (possibly in the future) for articles
generally.

@deftogether[(@defthing[articles-path path-string? #:value "articles"]
              @defthing[series-path   path-string? #:value "series"])]

The path of the folder that contains the Pollen source documents for Articles and Series
respectively, relative to the project’s document root.

@deftogether[(@defthing[articles-pagetree pagetree?]
              @defthing[series-pagetree pagetree?])]

These are project-wide pagetrees: @racket[articles-pagetree] contains a pagenode for every Pollen
document contained in @racket[articles-path], and @racket[series-pagetree] contains a pagenode for
every Pollen document in @racket[series-path]. The pagenodes themselves point to the rendered
@tt{.html} targets of the source documents.

@section{Metas and @code{txexpr}s}

@defproc[(attr-present? [name symbol?] [attrs (listof pair?)]) boolean?]

Shortsightedly redundant to @code{attrs-have-key?}. Returns @code{#t} if @racket[_name] is one of
the attributes present in @racket[_attrs], otherwise returns @code{#f}. 

;; Provides common helper functions used throughout the project

(provide maybe-meta     ; Select from (current-metas) or default value ("") if not available
         maybe-attr     ; Return an attribute’s value or a default ("") if not available
         series-noun    ; Retrieve noun-singular from current 'series meta, or ""
         series-title   ; Retrieve title of series in current 'series meta, or ""
         attr-present?  ; Test if an attribute is present
         tx-strs
         ymd->english
         ymd->dateformat
         default-authorname
         default-title
         articles-path
         series-path
         articles-pagetree
         series-pagetree
         first-words
         build-note-id
         notes->last-disposition-values
         disposition-values
         )

(define default-authorname "Joel Dueck")
(define series-path "series")
(define articles-path "articles")

(define (default-title date)
  (format "Entry of ~a" (ymd->dateformat date "d MMM YYYY")))

(define (maybe-meta m [missing ""])
  (or (select-from-metas m (current-metas)) missing))

;; Checks current-metas for a 'series meta and returns the pagenode of that series,
;; or '|| if no series is specified.
(define (series-pagenode)
  (define maybe-series (or (select-from-metas 'series (current-metas)) ""))
  (cond
    [(non-empty-string? maybe-series)
     (->pagenode (string-append series-path "/" maybe-series ".html"))]
    [else '||]))

(define (series-noun)
  (define series-pnode (series-pagenode)) 
  (case series-pnode
    ['|| ""] ; no series specified
    [else (or (select-from-metas 'noun-singular series-pnode) "")]))

(define (series-title)
  (define series-pnode (series-pagenode)) 
  (case series-pnode
    ['|| ""] ; no series specified
    [else (or (select-from-metas 'title series-pnode) "")]))

;; ~~~ Project-wide Pagetrees ~~~

(define (include-in-pagetree folder extension)
  (define (matching-file? f)
    (string-suffix? f extension))
  (define (file->output-pagenode f)
    (string->symbol (format "~a/~a" folder (string-replace f extension ".html"))))

  (define file-strs (map path->string (directory-list folder)))
  (map file->output-pagenode (filter matching-file? file-strs)))

(define articles-pagetree
  `(root ,@(include-in-pagetree articles-path ".poly.pm")))

(define series-pagetree
  `(root ,@(include-in-pagetree series-path ".poly.pm")))

;; ~~~ Convenience functions for tagged x-expressions ~~~

(define (attr-present? name attrs)
  (for/or ([attr-pair (in-list attrs)])
          (equal? name (car attr-pair))))

(define (maybe-attr name attrs [missing ""])
  (define result (assoc name attrs))
  (cond