edit:add-var pdf~ {|action @args|
  use math
  use os
  use path
  use re
  use str
  use framagit.org/benjamin.vaudour/elv-lib/mods/common
  use framagit.org/benjamin.vaudour/elv-lib/mods/format
  use framagit.org/benjamin.vaudour/elv-lib/mods/map
  use framagit.org/benjamin.vaudour/elv-lib/mods/pdf

  var -c~ = $common:cexec~
  var -cc~ = {|c f1| -c $c $f1 $nop~}

  fn must-pdf {|file| -cc (not (pdf:is-pdf $file)) { fail (printf '%s n’est pas un fichier pdf' $file) }}
  fn must-exist {|file| -cc (pdf:not-exist $file) { fail (printf '%s n’existe pas' $file) }}
  fn must-not-exist {|file| -cc (pdf:exist $file) { fail (printf '%s existe déjà' $file) }}
  fn must-pdf-exist {|file|
    must-pdf $file
    must-exist $file
  }
  fn must-pdf-not-exist {|file|
    must-pdf $file
    must-not-exist $file
  }
  fn must-valid {|v cond| -cc (not ($cond $v)) { fail (printf '%s: paramètre invalide' $v) }}

  fn out {|in suffix|
    var out = (str:trim-suffix $in .pdf)
    str:join '' [ $out $suffix ]
  }

  fn help {|@args| cat $E:HOME/.config/elvish/aliases/pdf.help}

  fn decrypt {|@args|
    var l = (count $args)
    -cc (or (< $l 1) (> $l 3)) { fail 'decrypt doit contenir entre 1 et 3 paramètres' }
    var in     = $args[0]
    var out    = (out $in _decrypted.pdf)
    var passwd = []
    must-pdf-exist $in
    if (> $l 1) {
      set @passwd = $args[1]
      if (> $l 2) {
        set out = $args[2]
      }
    }
    must-pdf-not-exist $out
    pdf:decrypt &out=$out $in $@passwd
  }

  fn rotate {|@args|
    var l = (- (count $args) 1)
    -cc (< $l 1) { fail 'rotate doit contenir au moins 1 paramètres' }
    var in  = $args[0]
    var out = (out $in _rotated.pdf)
    if (pdf:is-pdf $args[$l]) {
      set @args out = (all $args[1..])
    }
    must-pdf-exist $in
    must-pdf-not-exist $out
    each {|e|
      must-valid $e $pdf:is-rotate-selection~
    } $args
    pdf:rotate &keep=$true &out=$out $in $@args
  }

  fn merge {|@args|
    var l = (- (count $args) 1)
    -cc (< $l 1) { fail 'merge doit contenir au moins 2 paramètres' }
    var @selection out = $@args
    must-pdf-not-exist $out
    var has-in = $false
    each {|e|
      if (pdf:is-pdf $e) {
        must-exist $e
        set has-in = $true
      } else {
        -cc (not $has-in) { fail 'Une sélection doit être précédée d’un fichier d’entrée' }
        must-valid $e $pdf:is-selection~
      }
    } $selection
    pdf:cat &out=$out $@selection
  }

  fn unmerge {|@args|
    var l = (- (count $args) 1)
    -cc (< $l 1) { fail 'unmerge doit contenir au moins 2 paramètres' }
    var in  = $args[0]
    var out = (out $in _unmerged)
    if (not (pdf:is-selection $args[$l])) {
      set @args out = (all $args[1..])
    }
    must-pdf-exist $in
    must-not-exist $out
    each {|e|
      must-valid $e $pdf:is-selection~
    } $args
    pdf:uncat $in $out $@args
  }

  fn split {|@args|
    var l = (- (count $args) 1)
    -cc (< $l 1) { fail 'split doit contenir au moins 2 paramètres' }
    var out  = $args[$l]
    set args = $args[..$l]
    must-not-exist $out
    var s = 1
    if (pdf:is-number $args[0]) {
      set s @args = $@args
    }
    var t = (pdf:-t)
    try {
      pdf:cat &out=$t $@args
      pdf:split &size=$s $t $out
    } finally {
      os:remove-all $t
    }
  }

  fn split-at {|@args|
    var l = (count $args)
    -cc (!= $l 3) { fail 'split-at doit contenir 3 paramètres' }
    var rg in out = $@args
    must-pdf-exist $in
    must-not-exist $out
    must-valid $rg {|e| re:match '^\d+(,\d+)*$' $e }
    var b sel = 1 []
    str:split ',' $rg | order | each {|s|
      var e = (- $s 1)
      if (== $b $e) {
        set @sel = $@sel $b
        set b    = $s
      } elif (< $b $e) {
        set @sel = $@sel (printf '%d-%d' $b $e)
        set b    = $s
      }
    }
    set @sel = $@sel (printf '%d-z' $b)
    unmerge $in $@sel $out
  }

  fn zip {|@args|
    var l = (- (count $args) 1)
    -cc (< $l 1) { fail 'zip doit contenir au moins 2 paramètres' }
    var @selection out = $@args
    must-pdf-not-exist $out
    var has-in = $false
    each {|e|
      if (pdf:is-pdf $e) {
        must-exist $e
        set has-in = $true
      } else {
        -cc (not $has-in) { fail 'Une sélection doit être précédée d’un fichier d’entrée' }
        must-valid $e $pdf:is-selection~
      }
    } $selection
    pdf:cat &collate=$true &out=$out $@selection
  }

  fn unzip {|@args|
    var l = (- (count $args) 1)
    -cc (< $l 1) { fail 'unzip doit contenir au moins 2 paramètres' }
    var in @sel out = $@args
    var mod         = 2
    if (pdf:is-number $in) {
      set mod = $in
      -cc (eq (count $sel) 0) { fail 'unzip doit contenir au moins 3 paramètres' }
      set in @sel = $@sel
    }
    must-not-exist $out
    var t    = (pdf:-t)
    try {
      pdf:cat &out=$t $in $@sel
      var n = (pdf:nb-pages $t)
      os:mkdir $out
      range 1 (+ 1 $mod) | each {|m|
        var sel = (range 1 (+ $n 1) | each {|i|
          var s = (% $i $mod)
          -cc (== $s 0) { set s = $mod }
          -cc (== $s $m) $i
        } | each $to-string~ | str:join ',')
        pdf:cat &out=(printf '%s/%d.pdf' $out $m) $t $sel
      }
    } finally {
      os:remove-all $t
    }
  }

  fn pts2cm {|v| / (math:round (* $v 3.52778)) 100}
  fn -date {|raw|
    var y m d = $raw[2..6] $raw[6..8] $raw[8..10]
    var h n s = $raw[10..12] $raw[12..14] $raw[14..16]
    var rest  = []
    -cc (> (count $raw[16..]) 0) { set @rest = (str:split "'" $raw[16..]) }
    var tz    = '+00:00'
    if (> (count $rest) 0) {
      var tz = $rest[0]
      -cc (eq $tz[0] 'Z') { set tz = $tz[1..] }
      -cc (eq $tz '') { set tz = '00' }
      -cc (and (not-eq $tz[0] '+') (not-eq $tz[0] '-')) { set tz = (printf '+%s' $tz) }
      var mm = '00'
      -cc (and (> (count $rest) 1) (pdf:is-number $rest[1])) { set mm = $rest[1] }
      set tz = (printf '%s:%s' $tz $mm)
    }
    var date = (printf ^
      '%s-%s-%sT%s:%s:%sZ%s' ^
      $y $m $d ^
      $h $n $s ^
      $tz)
    date --date $date
  }

  fn info {|@args|
    -cc (!= (count $args) 1) { fail 'info doit contenir un paramètre' }
    var in @_ = $@args
    must-pdf-exist $in
    var json     = (pdf:json $in)
    var objects  = $json[objects]
    var trailer  = $objects[trailer]
    var infos    = $objects[$trailer[/Info]]
    var pages    = $json[pages]
    var p1       = $objects[$pages[0][object]]
    var w h      = (all $p1[/MediaBox][2..] | each $pts2cm~)
    var layout   = (-c (> $w $h) 'Paysage' 'Portrait')
    var title    = (map:value-of $infos '/Title')
    var subject  = (map:value-of $infos '/Subject')
    var author   = (map:value-of $infos '/Author')
    var creator  = (map:value-of $infos '/Creator')
    var producer = (map:value-of $infos '/Producer')
    var mdate    = (-c (has-key $infos '/ModDate') { -date $infos[/ModDate] } '')
    var crypted  = (-c (pdf:encryption $in)[encrypted] 'Oui' 'Non')
    var hasform  = ( -c (pdf:form $in)[hasacroform] 'Oui' 'Non')
    var data    = [
      [&k='Chemin'               &v=(path:abs $in)]
      [&k='Taille'               &v=(format:size (stat -c '%s' $in))]
      [&k='Version PDF'          &v=(pdf:version $in)]
      [&k='Nombre de pages'      &v=(count $pages)]
      [&k='Format des pages'     &v=(printf '%sx%s cm (%s)' $w $h $layout)]
      [&k='Titre'                &v=$title]
      [&k='Subjet'               &v=$subject]
      [&k='Auteur'               &v=$author]
      [&k='Créateur'             &v=$creator]
      [&k='producteur'           &v=$producer]
      [&k='Date de création'     &v=(-date $infos[/CreationDate])]
      [&k='Date de modification' &v=$mdate]
      [&k='Chiffré'              &v=$crypted]
      [&k='Acroform'             &v=$hasform]
    ]
    var label  = (format:repeat 21 ' ')
    var @props = (format:column &align=right k $label) (format:column v $label)
    set props  = (format:update-props $props $data)
    var sep    = (format:repeat (+ $props[0][size] $props[1][size] 3) '.')
    var @part  = $data[..5] $data[5..12] $data[12..]
    each {|d|
      format:list &with-header=$false &csep=' : ' &recompute=$false $props $@d
      echo $sep
    } $part
  }

  fn list-attachments {|in| all (pdf:attachments $in)}
  fn display-attachments {|in|
    var @data = (list-attachments $in)
    printf "%d pièce(s)-jointe(s) trouvée(s):\n\n" (count $data)
    each $echo~ $data
    echo
  }
  fn extract-attachments {|in out| list-attachments $in | each {|f| pdf:attachment $in $out/$f $f }}
  fn list-fonts {|in|
    pdf:fonts $in | each {|f|
      -cc (has-key $f /FontDescriptor) { put [&font=$f &fd=$f[/FontDescriptor]] }
    } | each {|f|
      -cc (has-key $f[fd] /FontName) { assoc $f name $f[fd][/FontName] }
    } | each {|f|
      var @_ n  = (str:split '+' $f[name])
      var font  = $f[font]
      var fd    = $f[fd]
      var embed = (has-key $fd /FontFile2)
      var file  = (-c $embed $fd[/FontFile2] '')
      set n = (str:trim-prefix $n '/')
      put [
        &id=$font[id]
        &name=$n
        &embed=$embed
        &file=$file
        &type=(str:trim-prefix $font[/Subtype] '/')
        &encoding=(str:trim-prefix $font[/Encoding] '/')
      ]
    }
  }
  fn display-fonts {|in|
    var @data = (list-fonts $in)
    printf "%d police(s) trouvée(s):\n\n" (count $data)
    var props = [
      (format:column &align=center id ID)
      (format:column name Nom)
      (format:column type Type)
      (format:column encoding Encodage)
      (format:column &align=center embed Téléchargeable)
      (format:column &align=center file Fichier)
    ]
    format:list $props $@data
    echo
  }
  fn extract-fonts {|in out|
    list-fonts $in | each {|f|
      -cc $f[embed] { pdf:filtered-stream $in (printf '%s/%s.ttf' $out $f[name]) $f[file] }
    }
  }
  fn list-images {|in|
    pdf:images $in | each {|i|
      var w = (format:int $i[/Width])
      var h = (format:int $i[/Height])
      var c = (-c (has-key $i /ColorSpace) { put $i[/ColorSpace][0] } '')
      put [
        &id=$i[id]
        &page=(format:int $i[page])
        &name=(str:trim-prefix $i[name] '/')
        &width=$w
        &height=$h
        &dim=(printf '%dx%d' $w $h)
        &filter=(str:trim-prefix $i[/Filter] '/')
        &size=(format:size $i[/Length])
        &bpc=(format:int $i[/BitsPerComponent])
        &color=(str:trim-prefix $c '/')
      ]
    }
    var objects = (pdf:objects $in)
    all (pdf:pages $in) | each {|p|
      var pn = (format:int $p[pageposfrom1])
      all $p[images] | each {|img|
        var id = $img[object]
        var o  = (pdf:-object &extend=$true $objects $id)
        var s  = $o[/Length]
        var c  = (-c (has-key $o /ColorSpace) { put $o[/ColorSpace][0] } '')
        var w  = (format:int $o[/Width])
        var h  = (format:int $o[/Height])
        put [
          &id=$id
          &page=$pn
          &name=(str:trim-prefix $img[name] '/')
          &width=$w
          &height=$h
          &dim=(printf '%dx%d' $w $h)
          &filter=(str:trim-prefix $o[/Filter] '/')
          &size=(format:size $s)
          &bpc=(format:int $o[/BitsPerComponent])
          &color=(str:trim-prefix $c '/')
        ]
      }
    }
  }
  fn display-images {|in|
    var @data = (list-images $in)
    printf "%d image(s) trouvée(s):\n\n" (count $data)
    var props = [
      (format:column &align=right page Page)
      (format:column &align=center id ID)
      (format:column name Nom)
      (format:column &align=right size Taille)
      (format:column &align=right dim Dimensions)
      (format:column color Couleur)
      (format:column &align=right bpc BPC)
      (format:column &align=center filter Filtre)
    ]
    format:list $props $@data
    echo
  }
  fn extract-images {|in out|
    # En attendant de savoir décoder correctement les images, on utilise poppler
    pdfimages -all $in $out/Im
  }

  fn list {|@args|
    -cc (!= (count $args) 2) { fail 'list doit comporter 2 paramètres' }
    var types in = $@args
    must-pdf-exist $in
    var display = [
      &a=$display-attachments~
      &f=$display-fonts~
      &i=$display-images~
    ]
    str:split ',' $types | each {|t|
      set t = (str:to-lower $t)
      must-valid $t {|e| and (> (count $e) 0) (has-key $display $e[0])}
      $display[$t[0]] $in
    }
  }

  fn extract {|@args|
  -cc (!= (count $args) 3) { fail 'extract doit comporter 3 paramètres' }
    var types in out = $@args
    must-pdf-exist $in
    must-not-exist $out
    var extr = [
      &a=$extract-attachments~
      &f=$extract-fonts~
      &i=$extract-images~
    ]
    try {
      os:mkdir $out
      str:split ',' $types | each {|t|
        set t = (str:to-lower $t)
        must-valid $t {|e| and (> (count $e) 0) (has-key $extr $e[0])}
        $extr[$t[0]] $in $out
      }
    } catch e {
      os:remove-all $out
      fail $e
    }
  }

  fn gray {|@args|
    -cc (!= (count $args) 2) { fail 'gray doit comporter 2 paramètres' }
    var in out = $@args
    must-pdf-exist $in
    must-pdf-not-exist $out
    convert -colorspace gray $in $out
  }

  fn mono {|@args|
    var c = (count $args)
    -cc (or (< $c 2) (> $c 3)) { fail 'mono doit comporter entre 2 et 3 paramètres' }
    var t = $nil
    if (pdf:is-number $args[0]) {
      set t @args = $@args
      -cc (or (< $t 0) (> $t 100)) { fail le taux doit être compris entre 0 et 100 }
      -cc (< $c 2) { fail 'mono doit comporter 3 paramètres' }
    }
    var in out = $@args
    must-pdf-exist $in
    must-pdf-not-exist $out
    if $t {
      convert -colorspace gray -threshold $t'%' $in $out
    } else {
      convert -monochrome $in $out
    }
  }

  var actions = [
    &help=$help~
    &decrypt=$decrypt~
    &rotate=$rotate~
    &merge=$merge~
    &cat=$merge~
    &unmerge=$unmerge~
    &uncat=$unmerge~
    &split=$split~
    &split-at=$split-at~
    &cut=$split-at~
    &zip=$zip~
    &unzip=$unzip~
    &info=$info~
    &list=$list~
    &extract=$extract~
    &gray=$gray~
    &mono=$mono~
    #&compress=$compress~
  ]
  -cc (not (has-key $actions $action)) { fail (printf '%s: action inconnue' $action) }
  $actions[$action] $@args
}