--[[   This module is intended to provide access to basic string functions.  Most of the functions provided here can be invoked with named parameters,  unnamed parameters, or a mixture. If named parameters are used, Mediawiki will  automatically remove any leading or trailing whitespace from the parameter.  Depending on the intended use, it may be advantageous to either preserve or remove such whitespace.  Global options  ignore_errors: If set to 'true' or 1, any error condition will result in   an empty string being returned rather than an error message.     error_category: If an error occurs, specifies the name of a category to   include with the error message. The default category is   [Category:Errors reported by Module String].    no_category: If set to 'true' or 1, no category will be added if an error  is generated.   Unit tests for this module are available at Module:String/tests. ]]  local p = {}  --[[ Helper function that populates the argument list given that user may need to use a mix of named and unnamed parameters. This is relevant because named parameters are not identical to unnamed parameters due to string trimming, and when dealing with strings we sometimes want to either preserve or remove that whitespace depending on the application. ]] function p.getParameters( frame_args, arg_list )  local new_args = {};  local index = 1;  local value;   for i,arg in ipairs( arg_list ) do  value = frame_args[arg]  if value == nil then  value = frame_args[index];  index = index + 1;  end  new_args[arg] = value;  end   return new_args; end  --[[ Helper Function to interpret boolean strings ]] function p.getBoolean( boolean_str )  local boolean_value;   if type( boolean_str ) == 'string' then  boolean_str = boolean_str:lower();  if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'  or boolean_str == '' then  boolean_value = false;  else  boolean_value = true;  end  elseif type( boolean_str ) == 'boolean' then  boolean_value = boolean_str;  else  error( 'No boolean value found' );  end  return boolean_value end  function p.defined(frame)  local arg = mw.text.trim(frame.args[1])  --if arg == tostring(tonumber(arg)) then -- undesired result for '-0'  -- arg = tonumber(arg)  --end  --if mw.ustring.find(arg, '^%s*-?[1-9][0-9]*%s*$') ~= nil or arg == '0' then  -- arg = tonumber(arg)  --end  if mw.ustring.find(arg, '^-?[1-9][0-9]*$') ~= nil then  arg = tonumber(arg)  elseif arg == '0' then  arg = 0  end  return frame:getParent().args[arg] ~= nil end  return p