Refactor the bangs script

Even at a couple hundred lines, it is slightly not good to navigate the
codebase. I'll just make it into `main`
ala-Rust/C/whatever-C-inspired-language.

bangs/config.json

@@ -18363,6 +18363,10 @@
     "name": "GitHub",
     "url": "https://github.com/search?utf8=%E2%9C%93&q={{{s}}}"
   },
+  "gh.nix": {
+    "name": "NixOS Packages",
+    "url": "https://github.com/NixOS/nixpkgs/search?q={{{s}}}"
+  },
   "gha": {
     "name": "GitHub Actions",
     "url": "https://github.com/marketplace?type=actions&query={{{s}}}"
@@ -32941,11 +32945,7 @@
   },
   "nixpkg": {
     "name": "NixOS Packages",
-    "url": "https://nixos.org/nixos/packages.html?query={{{s}}}"
+    "url": "https://search.nixos.org/packages?query={{{s}}}"
-  },
-  "nixpkgs": {
-    "name": "NixOS Packages",
-    "url": "https://nixos.org/nixos/packages.html?query={{{s}}}"
   },
   "nixtodon": {
     "name": "Nixtodon",

bin/bangs

@@ -36,48 +36,13 @@ Examples:
 HELP
 }
 
-# These are the default bangs available.
+# Simply prints the given string into percent-encoded equivalent.
-# Bangs are any keys that shouldn't have whitespace characters.
+#
-const config_dir = "${XDG_CONFIG_HOME:-"$HOME/.config"}/bangs"
+# > urlencode "Hello world"
-const config_file = "${config_dir}/config.json"
+#   Hello%20world
-const default_config = {
+#
-    'aw': {
+# Stolen from https://gist.github.com/cdown/1163649 and https://gist.github.com/cdown/1163649#gistcomment-1256298.
-        'name': 'Arch Wiki',
+# Just ported it in Oil script.
-        'url': 'https://wiki.archlinux.org/index.php?title=Special%3ASearch&search={{{s}}}'
-    },
-    'gh': {
-        'name': 'GitHub',
-        'url': 'https://github.com/search?utf8=%E2%9C%93&q={{{s}}}'
-    },
-    'g': {
-        'name': 'Google',
-        'url': 'https://www.google.com/search?q={{{s}}}'
-    },
-    'so': {
-        'name': 'Stack Overflow',
-        'url': 'http://stackoverflow.com/search?q={{{s}}}'
-    },
-    'w': {
-        'name': 'Wikipedia',
-        'url': 'https://en.wikipedia.org/wiki/Special:Search?search={{{s}}}'
-    }
-}
-
-const bangs_prefix = "${BANGS_PREFIX:-~}"
-const bangs_placeholder = "${BANGS_PLACEHOLDER:-{{{s}}}}"
-const bangs_format = / %start $bangs_prefix !space+ %end /
-const valid_bangs = %()
-const search_query = %()
-
-# Config file detection.
-# Otherwise, we'll just use the default config.
-if test -f $config_file {
-  json read :bangs < $config_file
-} else {
-  var bangs = default_config
-}
-
-# Stolen from https://gist.github.com/cdown/1163649 and https://gist.github.com/cdown/1163649#gistcomment-1256298
 proc urlencode(msg) {
   for (i in 0:len(msg)) {
     var char = msg[i]
@@ -93,39 +58,107 @@ proc urlencode(msg) {
   }
 }
 
+# `printf` except it prints in the stderr stream.
 proc warnf(format, @msg) {
   >&2 printf "$format\\n" @msg
 }
 
-if (len(ARGV) == 0) {
+# The entry point of this program.
-  usage
+proc main {
-  exit 0
+    # Config-related variables.
+    # For now, there is no system-related config.
+    # This is primarily a user script, after all. :)
+    const config_dir = "${XDG_CONFIG_HOME:-"$HOME/.config"}/bangs"
+    const config_file = "${config_dir}/config.json"
+
+    # Note you can configure these variables through the respective environment variables.
+    const bangs_prefix = "${BANGS_PREFIX:-~}"
+    const bangs_placeholder = "${BANGS_PLACEHOLDER:-{{{s}}}}"
+
+    # These are the default bangs available.
+    # Bangs are any keys that shouldn't have whitespace characters.
+    # We'll use this in case there is no user configuration.
+    #
+    # We also made the default config to be more flexible with the placeholder.
+    const default_config = {
+        'aw': {
+            'name': 'Arch Wiki',
+            'url': 'https://wiki.archlinux.org/index.php?title=Special%3ASearch&search=' + bangs_placeholder
+        },
+        'gh': {
+            'name': 'GitHub',
+            'url': 'https://github.com/search?utf8=%E2%9C%93&q=' + bangs_placeholder
+        },
+        'g': {
+            'name': 'Google',
+            'url': 'https://www.google.com/search?q=' + bangs_placeholder
+        },
+        'so': {
+            'name': 'Stack Overflow',
+            'url': 'http://stackoverflow.com/search?q=' + bangs_placeholder
+        },
+        'w': {
+            'name': 'Wikipedia',
+            'url': 'https://en.wikipedia.org/wiki/Special:Search?search=' + bangs_placeholder
+        }
+    }
+
+    # Setting up some variables.
+    const bangs_format = / %start $bangs_prefix !space+ %end /
+    const valid_bangs = %()
+    const search_query = %()
+
+    # Config file detection.
+    # Otherwise, we'll just use the default config.
+    if test -f $config_file {
+      json read :bangs < $config_file
+    } else {
+      var bangs = default_config
+    }
+
+    # Show the usage when no arguments was given like any sane program.
+    if (len(ARGV) == 0) {
+        usage
+            exit 0
+    }
+
+    # Filter out the bangs from the search query.
+    # The bangs are just words prefixed with a certain sequence of characters.
+    # We put both bangs and the search query in separate arrays for easier processing.
+    # E.g., in the search query `hello ~ddg world ~g`, `~ddg~ and `~g` are the bangs.
+    for i in @ARGV {
+        # If the argument is not a bang, append in the search query queue.
+        write -- $i | rg --quiet $bangs_format || {
+            append :search_query $i
+            continue
+        }
+
+        # Otherwise, put it in the bangs array.
+        # Keep in mind, we do throw out bangs that are not in the bangs database.
+        var bang = $(write -- $i | sed --regexp-extended --expression "s/^${bangs_prefix}//")
+        if (bang in bangs) {
+            append :valid_bangs $bang
+            warnf "%s will be used to search." $bang
+        } else {
+            warnf "%s is not found in the database." $bang
+        }
+    }
+
+    # Encode the query for a consistent formatting.
+    # Even though this script is in Oil where it has less problems with splitting strings, we still might want to encode the query for a good measure.
+    var query = join(search_query, " ")
+    var encoded_query = $(urlencode $query)
+
+    warnf "Search query is '%s'" $query
+    warnf "Encoded form is '%s'" $encoded_query
+
+    # Search the query with the given bangs.
+    for bang in @valid_bangs {
+        var metadata = bangs[bang]
+        var url = $(write -- ${metadata['url']} | sed --expression "s/${bangs_placeholder}/${encoded_query}/")
+
+        handlr open $url
+    }
 }
 
-for i in @ARGV {
+main @ARGV
-  write -- $i | rg --quiet $bangs_format || {
-    append :search_query $i
-    continue
-  }
-
-  var bang = $(write -- $i | sed --regexp-extended --expression "s/^${bangs_prefix}//")
-  if (bang in bangs) {
-    append :valid_bangs $bang
-    warnf "%s will be used to search." $bang
-  } else {
-    warnf "%s is not found in the database." $bang
-  }
-}
-
-var query = join(search_query, " ")
-var encoded_query = $(urlencode $query)
-
-warnf "Search query is '%s'" $query
-warnf "Encoded form is '%s'" $encoded_query
-
-for bang in @valid_bangs {
-  var metadata = bangs[bang]
-  var url = $(write -- ${metadata['url']} | sed --expression "s/${bangs_placeholder}/${encoded_query}/")
-
-  handlr open $url
-}