text: 'use strict';
  
  // MODULES //
  
  var isObject = require( 'validate.io-object' ),
  	isPositive = require( 'validate.io-positive' ),
  	isBoolean = require( 'validate.io-boolean-primitive' ),
  	isFunction = require( 'validate.io-function' ),
  	isString = require( 'validate.io-string-primitive' );
  
  
  // VALIDATE //
  
  /**
  * FUNCTION: validate( opts, options )
  *	Validates function options.
  *
  * @param {Object} opts - destination for validated options
  * @param {Object} options - function options
  * @param {Number} [options.lambda] - rate parameter
  * @param {Boolean} [options.copy] - boolean indicating if the function should return a new data structure
  * @param {Function} [options.accessor] - accessor function for accessing array values
  * @param {String} [options.sep] - deep get/set key path separator
  * @param {String} [options.path] - deep get/set key path
  * @param {String} [options.dtype] - output data type
  * @returns {Null|Error} null or an error
  */
  function validate( opts, options ) {
  	if ( !isObject( options ) ) {
  		return new TypeError( 'pdf()::invalid input argument. Options argument must be an object. Value: `' + options + '`.' );
  	}
  	if ( options.hasOwnProperty( 'lambda' ) ) {
  		opts.lambda = options.lambda;
  		if ( !isPositive( opts.lambda ) ) {
  			return new TypeError( 'pdf()::invalid option. `lambda` parameter must be a positive number. Option: `' + opts.lambda + '`.' );
  		}
  	}
  	if ( options.hasOwnProperty( 'copy' ) ) {
  		opts.copy = options.copy;
  		if ( !isBoolean( opts.copy ) ) {
  			return new TypeError( 'pdf()::invalid option. Copy option must be a boolean primitive. Option: `' + opts.copy + '`.' );
  		}
  	}
  	if ( options.hasOwnProperty( 'accessor' ) ) {
  		opts.accessor = options.accessor;
  		if ( !isFunction( opts.accessor ) ) {
  			return new TypeError( 'pdf()::invalid option. Accessor must be a function. Option: `' + opts.accessor + '`.' );
  		}
  	}
  	if ( options.hasOwnProperty( 'path' ) ) {
  		opts.path = options.path;
  		if ( !isString( opts.path ) ) {
  			return new TypeError( 'pdf()::invalid option. Key path option must be a string primitive. Option: `' + opts.path + '`.' );
  		}
  	}
  	if ( options.hasOwnProperty( 'sep' ) ) {
  		opts.sep = options.sep;
  		if ( !isString( opts.sep ) ) {
  			return new TypeError( 'pdf()::invalid option. Separator option must be a string primitive. Option: `' + opts.sep + '`.' );
  		}
  	}
  	if ( options.hasOwnProperty( 'dtype' ) ) {
  		opts.dtype = options.dtype;
  		if ( !isString( opts.dtype ) ) {
  			return new TypeError( 'pdf()::invalid option. Data type option must be a string primitive. Option: `' + opts.dtype + '`.' );
  		}
  	}
  	return null;
  } // end FUNCTION validate()
  
  
  // EXPORTS //
  
  module.exports = validate;
  