Update lang files and readme

- Revise lang files: use `string.format()`, clean up template and
  message placeholders, include comments for translated lines
  (thanks to lucidiot for FR translation and suggestions)
- Clarify dependencies in build instructions

env.lua

@@ -5,7 +5,7 @@ env.app = {
   name = "gemwriter",
   exec_name = "gemwriter",
   version = "0.3",
-  last_updated = "2022-08-05",
+  last_updated = "2022-08-06",
 }
 
 env.defaults = {
@@ -18,6 +18,7 @@ env.defaults = {
     page = "page.gmi",
     post = "post.gmi",
   },
+  lang_opts = { "en_US", "fr_FR" },
   post_slug = "untitled",
   post_slug_date_format = "%Y-%m-%d",
   -- Atom feed date format
@@ -27,13 +28,24 @@ env.defaults = {
   page_slug = os.date("%Y%m%d-%H%M%S"),
 }
 
+-- Command-line keywords
+env.cli_opts = {
+  config = "config",
+  page = "page",
+  post = "post",
+  index = "index",
+  publish = "publish",
+  help = "help",
+  version = "version",
+}
+
 -- Configurable settings
 env.toml_vars = {
   general = "general",
   capsules = "capsules",
 }
 env.general = {
-  app_lang = "en",
+  app_lang = "en_US",
   main_capsule = "main",
 }
 env.capsules = {

gemwriter.lua

@@ -1,5 +1,5 @@
 local env = require("env")
-local lang = require("lang.en")
+local lang = require("lang.en_US")
 local util = require("util")
 
 
@@ -8,11 +8,32 @@ writer.docs = {}
 writer.conf = {}
 writer.posts = {}
 
+
+writer.docs.get_lang_opts = [[
+  Return a table of available language translations for the app interface.
+  ]]
+function writer.get_lang_opts()
+  local lang_opts = {}
+  for l = 1, #env.defaults.lang_opts do
+    if util.module_exists("lang." .. env.defaults.lang_opts[l]) then
+      table.insert(lang_opts, env.defaults.lang_opts[l])
+    end
+  end
+  return lang_opts
+end
+
+
 writer.docs.gen_config = [[
   Generate a default config directory.
   ]]
-function writer.gen_config()
+function writer.gen_config(lang_pref)
-  writer.conf.config_dir = util.replace_shell_vars(env.defaults.config_dir)
+  -- Set lang
+  if lang_pref ~= nil and util.module_exists("lang." .. lang_pref) then
+    lang = require("lang." .. lang_pref)
+    env.defaults_toml = string.gsub(env.defaults_toml, env.general.app_lang,
+      lang_pref)
+  end
+
   util.make_dir(writer.conf.config_dir)
   for name, file in pairs(env.defaults.config_files) do
     -- Check each file individually anyway to avoid overwriting existing
@@ -106,7 +127,9 @@ function writer.parse_config(config_file)
   end
 
   -- Set lang
-  lang = require("lang." .. writer.conf.app_lang)
+  if util.module_exists("lang." .. writer.conf.app_lang) then
+    lang = require("lang." .. writer.conf.app_lang)
+  end
 
   -- Custom templates override lang defaults (ignore config)
   for name, file in pairs(env.defaults.config_files) do
@@ -119,40 +142,23 @@ end
 
 
 writer.docs.load_config = [[
-  Check whether there is an existing config and load it if found. Exit if a
+  Load an existing config. Exit if a capsule is not found.
-  capsule is not found.
   ]]
 function writer.load_config(cap_id)
-  writer.conf.config_dir = util.replace_shell_vars(env.defaults.config_dir)
+  -- Check capsule id exists, abort if no valid capsule found
-  local config_file = util.read_file(writer.conf.config_dir .. "/" ..
+  if (cap_id == nil) or (string.find(cap_id, " ") ~= nil) then
-    env.defaults.config_files.config)
+    writer.conf.cap_id = env.general.main_capsule
-  local config_new = false
+  else
-
+    writer.conf.cap_id = cap_id
-  -- No config found
-  if (config_file == "") and (not config_new) then
-    writer.gen_config()
-    config_new = true
   end
-
+  local cap_label = "%[" .. env.toml_vars.capsules .. "%." ..
-  -- Config found, read the configuration and load the values to an
+    tostring(cap_id) .. "%]"
-  -- associative table, writer.conf.
+  if (string.find(writer.conf.config_file, cap_label) == nil) and
-  if (config_file ~= "") and (not config_new) then
+    (writer.conf.cap_id ~= env.general.main_capsule) then
-    -- Check capsule id exists, abort if no valid capsule found
+    print(lang.errs.invalid_cap_id)
-    if (cap_id == nil) or (string.find(cap_id, " ") ~= nil) then
+    os.exit()
-      writer.conf.cap_id = env.general.main_capsule
-    else
-      writer.conf.cap_id = cap_id
-    end
-    local cap_label = "%[" .. env.toml_vars.capsules .. "%." ..
-      tostring(cap_id) .. "%]"
-    if (string.find(config_file, cap_label) == nil) and
-      (writer.conf.cap_id ~= env.general.main_capsule) then
-      print(lang.errs.invalid_cap_id)
-      os.exit()
-    end
-
-    writer.parse_config(config_file)
   end
+  writer.parse_config(writer.conf.config_file)
 end
 
 
@@ -348,40 +354,58 @@ cli.docs.handle_args = [[
   any additional arguments to the functions.
   ]]
 function cli.handle_args(args)
-  if (args[1] ~= lang.opts.help) and (args[1] ~= lang.opts.version) then
+  if (args[1] ~= env.cli_opts.help) or (args[1] ~= env.cli_opts.version) then
-    writer.load_config(args[2])
+    local config_new = false
+    writer.conf.config_dir = util.replace_shell_vars(env.defaults.config_dir)
+    writer.conf.config_file = util.read_file(writer.conf.config_dir .. "/" ..
+      env.defaults.config_files.config)
+    -- No config found
+    if (writer.conf.config_file == "") and (not config_new) then
+      writer.gen_config(args[2])
+      config_new = true
+    end
+    -- Config found, read the configuration and load the values to an
+    -- associative table, writer.conf.
+    if (writer.conf.config_file ~= "") and (not config_new) then
+      writer.load_config(args[2])
+    end
   end
 
-  if (args[1] == lang.opts.index) or (args[1] == lang.opts.publish) then
+  if (args[1] == env.cli_opts.index) or (args[1] == env.cli_opts.publish) then
     writer.posts = writer.get_posts_meta()
     if writer.conf.cap.gen_index_page then writer.gen_index_page() end
     if writer.conf.cap.gen_atom_feed then writer.gen_atom_feed() end
   end
 
-  if args[1] == lang.opts.config then
+  if args[1] == env.cli_opts.config then
-    writer.load_config()
+    writer.gen_config(args[2])
-    print(lang.msgs.load_config .. writer.conf.config_dir)
+    print(string.format(lang.msgs.load_config, writer.conf.config_dir))
 
-  elseif (args[1] == lang.opts.post) or (args[1] == lang.opts.page) then
+  elseif (args[1] == env.cli_opts.post) or (args[1] == env.cli_opts.page) then
     local file_name = ""
     if args[3] ~= nil then
       file_name = writer.add_gemtext(args[3], args[1])
     else
       file_name = writer.add_gemtext(args[2], args[1])
     end
-    print(lang.msgs.add_gemtext .. file_name)
+    print(string.format(lang.msgs.add_gemtext, file_name))
 
-  elseif args[1] == lang.opts.index then
+  elseif args[1] == env.cli_opts.index then
     print(lang.msgs.index)
 
-  elseif args[1] == lang.opts.publish then
+  elseif args[1] == env.cli_opts.publish then
     writer.publish()
     print(lang.msgs.publish)
 
-  elseif args[1] == lang.opts.help then
+  elseif args[1] == env.cli_opts.help then
-    print(env.app.exec_name .. lang.msgs.help)
+    print(string.format(lang.msgs.help_usage, env.app.exec_name) ..
+      string.format(lang.msgs.help_opts, env.cli_opts.config,
+      env.cli_opts.page, env.cli_opts.post, env.cli_opts.index,
+      env.cli_opts.publish, env.cli_opts.help, env.cli_opts.version) ..
+      string.format(lang.msgs.help_lang_opts,
+        table.concat(writer.get_lang_opts(), ", ")))
 
-  elseif args[1] == lang.opts.version then
+  elseif args[1] == env.cli_opts.version then
     print(env.app.name .. " " .. env.app.version ..
       " (" .. env.app.last_updated .. ")")
   end

lang/en.lua

@@ -1,145 +0,0 @@
-local en = {}
-
--- Templates
-en.tpl_vars = {
-  post = {
-    author = "{{ post_author }}",
-    content = "{{ post_content }}",
-    date = "{{ post_date }}",
-    summary = "{{ post_summary }}",
-    tags = "{{ post_tags }}",
-    title = "{{ post_title }}",
-    url = "{{ post_url }}",
-  },
-  feed = {
-    date = "{{ feed_date }}",
-    url = "{{ feed_url }}",
-  },
-  index = {
-    posts = "{{ posts }}",
-  },
-  log = {
-    author = "{{ log_author }}",
-    subtitle = "{{ log_subtitle }}",
-    title = "{{ log_title }}",
-    log_url = "{{ log_url }}",
-  },
-}
-
-en.atom_header = [[<?xml version="1.0" encoding="UTF-8"?>
-<feed xmlns="http://www.w3.org/2005/Atom">
-  <title>{{ log_title }}</title>
-  <subtitle>{{ log_subtitle }}</subtitle>
-  <updated>{{ feed_date }}</updated>
-  <author>
-    <name>{{ log_author }}</name>
-  </author>
-  <id>{{ feed_url }}</id>
-  <link href="{{ log_url }}" rel="alternate"/>
-  <link href="{{ feed_url }}" rel="self" type="application/atom+xml"/>
-]]
-
-en.atom_entry = [[
-  <entry>
-    <id>{{ post_url }}</id>
-    <title>
-      <![CDATA[{{ post_title }}]] .. "]]>" .. [[
-
-    </title>
-    <updated>{{ post_date }}</updated>
-    <author>
-      <name>{{ post_author }}</name>
-    </author>
-    <link href="{{ post_url }}" rel="alternate"/>
-    <summary>
-      <![CDATA[{{ post_summary }}]] .. "]]>" .. [[
-
-    </summary>
-    <content>
-      <![CDATA[{{ post_content }}]] .. "]]>" .. [[
-
-    </content>
-  </entry>
-]]
-
-en.atom_footer = [[</feed>]]
-
-en.post = [[---
-date: {{ post_date }}
----
-
-# {{ post_title }}
-
-
-
-
-## Links
-
-=> gemini:// link
-=> gemini:// link (img)
-=> https:// link (https)]]
-
-en.index = [[
-# {{ log_title }}
-{{ posts }}
-]]
-
-en.page = [[
-# {{ post_title }}
-
-## Heading 2
-### Heading 3
-
-List:
-
-*
-*
-*
-
-```
-Preformatted text
-```
-
-
-## Links
-
-=> gemini:// link
-=> gemini:// link (img)
-=> https:// link (https)]]
-
--- App command options and messages output
-en.opts = {
-  config = "config",
-  page = "page",
-  post = "post",
-  index = "index",
-  publish = "publish",
-  help = "help",
-  version = "version",
-}
-
-en.msgs = {
-  add_gemtext = "Created ",
-  help = [[ [options] [capsule] [title]
-
-Options:
-
-config                    Generate a config directory
-page [capsule] [title]    Add a new page with the given title
-post [capsule] [title]    Add a new gemlog post with the given title
-index                     Generate an index page and feed of posts
-publish                   Index and copy posts remotely using scp
-help                      Show this help message
-version                   Print version info]],
-  index = "Created index page and feed.",
-  load_config = [[Created config files. Please edit them with the correct
-details before proceeding. The config files can be found at:
-]],
-  publish = "Published capsule.",
-}
-
-en.errs = {
-  invalid_cap_id = "Error: unknown capsule id.",
-}
-
-return en

lang/en_US.lua

@@ -0,0 +1,157 @@
+local en = {}
+
+-- Templates
+en.tpl_vars = {
+  post = {
+    author = "{{ author }}",
+    content = "{{ content }}",
+    date = "{{ date }}",
+    summary = "{{ summary }}",
+    -- This is not used in the templates yet.
+    tags = "{{ tags }}",
+    title = "{{ title }}",
+    url = "{{ url }}",
+  },
+  feed = {
+    date = "{{ date }}",
+    url = "{{ feed_url }}",
+  },
+  index = {
+    posts = "{{ posts }}",
+  },
+  log = {
+    author = "{{ author }}",
+    subtitle = "{{ subtitle }}",
+    title = "{{ title }}",
+    url = "{{ log_url }}",
+  },
+}
+
+en.atom_header = [[<?xml version="1.0" encoding="UTF-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+  <title>{{ title }}</title>
+  <subtitle>{{ subtitle }}</subtitle>
+  <updated>{{ date }}</updated>
+  <author>
+    <name>{{ author }}</name>
+  </author>
+  <id>{{ feed_url }}</id>
+  <link href="{{ log_url }}" rel="alternate"/>
+  <link href="{{ feed_url }}" rel="self" type="application/atom+xml"/>
+]]
+
+en.atom_entry = [[
+  <entry>
+    <id>{{ url }}</id>
+    <title>
+      <![CDATA[{{ title }}]] .. "]]>" .. [[
+
+    </title>
+    <updated>{{ date }}</updated>
+    <author>
+      <name>{{ author }}</name>
+    </author>
+    <link href="{{ url }}" rel="alternate"/>
+    <summary>
+      <![CDATA[{{ summary }}]] .. "]]>" .. [[
+
+    </summary>
+    <content>
+      <![CDATA[{{ content }}]] .. "]]>" .. [[
+
+    </content>
+  </entry>
+]]
+
+en.atom_footer = [[</feed>]]
+
+en.post = [[---
+date: {{ date }}
+---
+
+# {{ title }}
+
+
+
+
+## Links
+
+=> gemini:// link
+=> gemini:// link (img)
+=> https:// link (https)]]
+
+en.index = [[
+# {{ title }}
+{{ posts }}
+]]
+
+en.page = [[
+# {{ title }}
+
+## Heading 2
+### Heading 3
+
+List:
+
+*
+*
+*
+
+```
+Preformatted text
+```
+
+
+## Links
+
+=> gemini:// link
+=> gemini:// link (img)
+=> https:// link (https)]]
+
+
+en.msgs = {}
+
+-- %s: gemtext filename
+en.msgs.add_gemtext = "Created %s."
+
+-- %s: app executable name
+en.msgs.help_usage = [[%s [options] [capsule] [title]
+
+]]
+
+-- %s: command-line options
+-- (see env.lua env.cli_opts for the full list)
+en.msgs.help_opts = [[
+Options:
+
+%s [lang]             Generate a config directory
+%s [capsule] [title]    Add a new page with the given title
+%s [capsule] [title]    Add a new gemlog post with the given title
+%s                     Generate an index page and feed of posts
+%s                   Index and copy posts remotely using scp
+%s                      Show this help message
+%s                   Print version info
+]]
+
+-- %s: list of language codes
+en.msgs.help_lang_opts = [[
+
+Config language options:
+
+%s]]
+
+en.msgs.index = "Created index page and feed."
+
+-- %s: config directory path
+en.msgs.load_config = [[Created config files. Please edit them with the correct
+details before proceeding. The config files can be found at:
+%s]]
+
+en.msgs.publish = "Published capsule."
+
+
+en.errs = {
+  invalid_cap_id = "Error: unknown capsule id.",
+}
+
+return en

lang/fr.lua

@@ -1,157 +0,0 @@
-local fr = {}
-
--- Templates
-fr.tpl_vars = {
-  post = {
-    -- It might not be really necessary to mention post/feed/log each time
-    -- since those occur in different templates?
-    -- This would make the french translated tags much cleaner, because the
-    -- proper way to do this translation would be "auteur_de_l'article"
-    -- (author_of_the_post).
-    author = "{{ auteur_article }}",
-    content = "{{ contenu_article }}",
-    date = "{{ date_article }}",
-    summary = "{{ résumé_article }}",
-    -- This is not used in the templates.
-    tags = "{{ tags_article }}",
-    title = "{{ titre_article }}",
-    url = "{{ url_article }}",
-  },
-  feed = {
-    date = "{{ date_flux }}",
-    url = "{{ url_flux }}",
-  },
-  index = {
-    posts = "{{ articles }}",
-  },
-  log = {
-    -- The concept of a "gemlog" does not have a French translation
-    -- as far as I know, so I used 'capsule' instead of 'log'.
-    author = "{{ auteur_capsule }}",
-    subtitle = "{{ sous_titre_capsule }}",
-    title = "{{ titre_capsule }}",
-    log_url = "{{ url_capsule }}",
-  },
-}
-
-fr.atom_header = [[<?xml version="1.0" encoding="UTF-8"?>
-<feed xmlns="http://www.w3.org/2005/Atom">
-  <title>{{ titre_capsule }}</title>
-  <subtitle>{{ sous_titre_capsule }}</subtitle>
-  <updated>{{ date_flux }}</updated>
-  <author>
-    <name>{{ auteur_capsule }}</name>
-  </author>
-  <id>{{ url_flux }}</id>
-  <link href="{{ url_capsule }}" rel="alternate"/>
-  <link href="{{ url_flux }}" rel="self" type="application/atom+xml"/>
-]]
-
-fr.atom_entry = [[
-  <entry>
-    <id>{{ url_article }}</id>
-    <title>
-      <![CDATA[{{ titre_article }}]] .. "]]>" .. [[
-
-    </title>
-    <updated>{{ date_article }}</updated>
-    <author>
-      <name>{{ auteur_article }}</name>
-    </author>
-    <link href="{{ url_article }}" rel="alternate"/>
-    <summary>
-      <![CDATA[{{ résumé_article }}]] .. "]]>" .. [[
-
-    </summary>
-    <content>
-      <![CDATA[{{ contenu_article }}]] .. "]]>" .. [[
-
-    </content>
-  </entry>
-]]
-
-fr.atom_footer = [[</feed>]]
-
-fr.post = [[---
-date: {{ date_article }}
----
-
-# {{ titre_article }}
-
-
-
-
-## Liens
-
-=> gemini:// lien
-=> gemini:// lien (image)
-=> https:// lien (https)]]
-
-fr.index = [[
-# {{ titre_capsule }}
-{{ articles }}
-]]
-
-fr.page = [[
-# {{ titre_article }}
-
-## Titre de niveau 2
-### Titre de niveau 3
-
-Liste :
-
-*
-*
-*
-
-```
-Texte préformaté
-```
-
-
-## Liens
-
-=> gemini:// lien
-=> gemini:// lien (image)
-=> https:// lien (https)]]
-
--- App command options and messages output
--- These probably should always stay untranslated, because having a CLI's
--- entire command line change depending on the language would be a mess.
--- Imagine writing bash in french…
-fr.opts = {
-  config = "config",
-  page = "page",
-  post = "post",
-  index = "index",
-  publish = "publish",
-  help = "help",
-  version = "version",
-}
-
-fr.msgs = {
-  add_gemtext = "Créé ",
-  help = [[ [options] [capsule] [titre]
-
-Options :
-
-config                    Générer un dossier de configuration
-page [capsule] [titre]    Ajouter une nouvelle page avec le titre fourni
-post [capsule] [titre]    Ajouter un nouvel article avec le titre fourni
-index                     Générer une page d'accueil et un flux d'articles
-publish                   Générer les pages puis les publier via scp
-help                      Afficher ce message d'aide
-version                   Afficher les informations de version]],
-  index = "Flux et page d'accueil créés.",
-  load_config = [[Les fichiers de configuration ont été créés. Veuillez y
-inscrire les valeurs correctes avant de continuer.
-Les fichiers peuvent être trouvés dans :
-]],
-  publish = "Capsule publiée.",
-}
-
-fr.errs = {
-  invalid_cap_id = "Erreur: Identifiant de capsule inconnu.",
-}
-
-return fr

lang/fr_FR.lua

@@ -0,0 +1,160 @@
+local fr = {}
+
+-- Templates
+fr.tpl_vars = {
+  post = {
+    author = "{{ auteur }}",
+    content = "{{ contenu }}",
+    date = "{{ date }}",
+    summary = "{{ résumé }}",
+    -- This is not used in the templates yet.
+    tags = "{{ tags }}",
+    title = "{{ titre }}",
+    url = "{{ url }}",
+  },
+  feed = {
+    date = "{{ date }}",
+    url = "{{ url_flux }}",
+  },
+  index = {
+    posts = "{{ articles }}",
+  },
+  log = {
+    -- The concept of a "gemlog" does not have a French translation,
+    -- the closest term after some discussion might be "journal".
+    author = "{{ auteur }}",
+    subtitle = "{{ sous_titre }}",
+    title = "{{ titre }}",
+    log_url = "{{ url_journal }}",
+  },
+}
+
+fr.atom_header = [[<?xml version="1.0" encoding="UTF-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+  <title>{{ titre }}</title>
+  <subtitle>{{ sous_titre }}</subtitle>
+  <updated>{{ date }}</updated>
+  <author>
+    <name>{{ auteur }}</name>
+  </author>
+  <id>{{ url_flux }}</id>
+  <link href="{{ url_journal }}" rel="alternate"/>
+  <link href="{{ url_flux }}" rel="self" type="application/atom+xml"/>
+]]
+
+fr.atom_entry = [[
+  <entry>
+    <id>{{ url }}</id>
+    <title>
+      <![CDATA[{{ titre }}]] .. "]]>" .. [[
+
+    </title>
+    <updated>{{ date }}</updated>
+    <author>
+      <name>{{ auteur }}</name>
+    </author>
+    <link href="{{ url }}" rel="alternate"/>
+    <summary>
+      <![CDATA[{{ résumé }}]] .. "]]>" .. [[
+
+    </summary>
+    <content>
+      <![CDATA[{{ contenu }}]] .. "]]>" .. [[
+
+    </content>
+  </entry>
+]]
+
+fr.atom_footer = [[</feed>]]
+
+fr.post = [[---
+date: {{ date }}
+---
+
+# {{ titre }}
+
+
+
+
+## Liens
+
+=> gemini:// lien
+=> gemini:// lien (image)
+=> https:// lien (https)]]
+
+fr.index = [[
+# {{ titre }}
+{{ articles }}
+]]
+
+fr.page = [[
+# {{ titre }}
+
+## Titre de niveau 2
+### Titre de niveau 3
+
+Liste :
+
+*
+*
+*
+
+```
+Texte préformaté
+```
+
+
+## Liens
+
+=> gemini:// lien
+=> gemini:// lien (image)
+=> https:// lien (https)]]
+
+
+fr.msgs = {}
+
+-- %s: gemtext filename
+fr.msgs.add_gemtext = "%s créé."
+
+-- %s: app executable name
+fr.msgs.help_usage = [[%s [options] [capsule] [titre]
+
+]]
+
+-- %s: command-line options
+-- (see env.lua env.cli_opts for the full list)
+fr.msgs.help_opts = [[
+Options :
+
+%s [lang]             Générer un dossier de configuration
+%s [capsule] [titre]    Ajouter une nouvelle page avec le titre fourni
+%s [capsule] [titre]    Ajouter un nouvel article avec le titre fourni
+%s                     Générer une page d'accueil et un flux d'articles
+%s                   Générer les pages puis les publier via scp
+%s                      Afficher ce message d'aide
+%s                   Afficher les informations de version
+]]
+
+-- %s: list of language codes
+fr.msgs.help_lang_opts = [[
+
+Langues disponibles :
+
+%s]]
+
+fr.msgs.index = "Flux et page d'accueil créés."
+
+-- %s: config directory path
+fr.msgs.load_config = [[Les fichiers de configuration ont été créés. Veuillez y
+inscrire les valeurs correctes avant de continuer.
+Les fichiers peuvent être trouvés dans :
+%s]]
+
+fr.msgs.publish = "Capsule publiée."
+
+
+fr.errs = {
+  invalid_cap_id = "Erreur: Identifiant de capsule inconnu.",
+}
+
+return fr

readme.md

@@ -25,17 +25,20 @@ version                   Print version info
 
 ## Build
 
-- Install Lua and [luastatic].
+- Install Lua (including development libraries and headers) and [luastatic].
 
 - Clone this repository and change into the directory. Run:
 
   ```
-  luastatic gemwriter.lua env.lua util.lua lang/en.lua \
+  luastatic gemwriter.lua env.lua util.lua lang/*.lua \
-    /usr/lib/liblua.so -I/usr/include -o gemwriter
+    /usr/lib/[arch]/liblua[5.x].a -I/usr/include/lua[5.x] -static \
+    -o gemwriter
   ```
 
-  The paths to `liblua.so` and the development headers (i.e.
+  Replace `[arch]` with the OS architecture, e.g. `x86_64-linux-gnu`, and
-  `/usr/include/lua.h`) may need to be adjusted for your distribution.
+  `[5.x]` with the Lua version. The paths to `liblua.a` and the development
+  headers (i.e.  `/usr/include/lua[5.x]/lua.h`) may need to be adjusted for
+  your distribution.
 
 - Move the `gemwriter` executable to a location in your `$PATH`.
 
@@ -52,6 +55,13 @@ version                   Print version info
 4. Publish your capsule: `gemwriter publish`
 
 
+## Credits
+
+Special thanks to the following contributors:
+
+- [lucidiot](https://tilde.town/~lucidiot/) — French translation
+
+
 ## License
 
 BSD-3-Clause

util.lua

@@ -139,6 +139,16 @@ function util.extract_file_date(dir, file)
 end
 
 
+function util.module_exists(mod)
+  local check, err = pcall(require, mod)
+  if check then do
+    return true end
+  else
+    return false
+  end
+end
+
+
 function util.read_file(file)
   local fh = io.open(file, "r")
   local text = ""