[#245] Convert helper into a module

modules/helper/init.zsh

@@ -0,0 +1,32 @@
+#
+# Defines helper functions.
+#
+# Authors:
+#   Sorin Ionescu <sorin.ionescu@gmail.com>
+#
+
+# Checks a boolean variable for "true".
+# Case insensitive: "1", "y", "yes", "t", "true", "o", and "on".
+function is-true {
+  [[ -n "$1" && "$1" == (1|[Yy]([Ee][Ss]|)|[Tt]([Rr][Uu][Ee]|)|[Oo]([Nn]|)) ]]
+}
+
+# Checks a name if it is a command, function, or alias.
+function is-callable {
+  (( $+commands[$1] )) || (( $+functions[$1] )) || (( $+aliases[$1] ))
+}
+
+# Prints the first non-empty string in the arguments array.
+function coalesce {
+  for arg in $argv; do
+    print "$arg"
+    return 0
+  done
+  return 1
+}
+
+# Checks if a file can be autoloaded by trying to load it in a subshell.
+function autoloadable {
+  ( unfunction $1 ; autoload -U +X $1 ) &> /dev/null
+}
+

modules/prompt/functions/prompt_sorin_setup

@@ -8,6 +8,9 @@
 #   http://i.imgur.com/4CeOj.png
 #
 
+# Load dependencies.
+pmodload 'helper'
+
 function prompt_sorin_precmd {
   setopt LOCAL_OPTIONS
   unsetopt XTRACE KSH_ARRAYS

modules/ssh-agent/init.zsh

@@ -11,6 +11,9 @@
 #   Sorin Ionescu <sorin.ionescu@gmail.com>
 #
 
+# Load dependencies.
+pmodload 'helper'
+
 # Return if requirements are not found.
 if (( ! $+commands[ssh-agent] )); then
   return 1

modules/utility/init.zsh

@@ -8,7 +8,7 @@
 #
 
 # Load dependencies.
-pmodload 'spectrum'
+pmodload 'helper' 'spectrum'
 
 # Correct commands.
 setopt CORRECT