bashrc: checking if the environment is loaded before executing stuff that relies on it

.bashrc

@@ -9,11 +9,49 @@ if (( BASH_VERSINFO[0] < 4 )); then
   echo "Please get a newer version of Bash."
   echo "Your bashrc won't work otherwise."
 else
-  # Source .bashrc.d
-  for file in ~/.bashrc.d/*.bashrc; do
-    . "$file"
-  done
 
-  unset -v file
+  # Basic safe boolean evaluation. See this Gist for details:
+  # https://gist.github.com/gliech/184dc7566821442202f21dfe15e2b7ff
+  function truthy {
+    if [[ "${1,,}" == @(y|yes|on|true|1) ]]; then
+      return 0
+    fi
+    return 1
+  }
+
+  function falsy {
+    if [[ "${1,,}" == @(n|no|off|false|0) ]]; then
+      return 0
+    fi
+    return 1
+  }
+
+  function true_false_default {
+    case "${1,,}" in
+      y | yes | on | true | 1)
+        return 0 ;;
+      n | no | off | false | 0)
+        return 1 ;;
+    esac
+    shift
+    eval "$@"
+    return 1
+  }
+
+  export -f truthy falsy true_false_default
+
+  if truthy $DOTFILES_ACTIVE; then
+
+    # Source .bashrc.d
+    for file in ~/.bashrc.d/*.bashrc; do
+      . "$file"
+    done
+
+    unset -v file
+
+  elif [[ ! -v DOTFILES_ACTIVE ]]; then
+    echo "Dotfiles environment not found."
+    echo "You should probably reload your login session before proceeding."
+  fi
 fi
 

.environment.d/dotfiles.env

@@ -0,0 +1,4 @@
+DOTFILES_ACTIVE=true
+DOTFILES_DIR="${HOME}/.dotfiles"
+DOTFILES_GITDIR="${HOME}/.dotgit"
+