diff --git a/lib/util_mustache.js b/lib/util_mustache.js
index b88f3da..26b05e7 100644
--- a/lib/util_mustache.js
+++ b/lib/util_mustache.js
@@ -12,8 +12,25 @@
 
 // the term "alphanumeric" includes underscores.
 
-// todo: document this exact regex long form.
-var partialsRE = new RegExp(/{{>\s*?([\w\-\.\/~]+)(?:\:[A-Za-z0-9-_|]+)?(?:(?:| )\(.*)?(?:\s*)?}}/g);
+// look for an opening mustache include tag, followed by >=0 whitespaces
+var partialsStr = '{{>\\s*';
+
+// one or more characters comprising any combination of alphanumerics,
+// hyphens, periods, slashses, and tildes
+partialsStr += '([\\w\\-\\.\\/~]+)';
+
+// an optional group comprising a colon followed by one or more characters
+// comprising any combination of alphanumerics, hyphens, and pipes
+partialsStr += '(\\:[\\w\\-\\|]+)?';
+
+// an optional group of characters starting with >=0 whitespaces, followed by an
+// opening parenthesis, followed by a lazy match of non-whitespace or whitespace
+// characters (to include newlines), followed by a closing parenthesis
+partialsStr += '(\\s*\\([\\S\\s]*?\\))?';
+
+// look for >=0 whitespaces, followed by closing mustache tag
+partialsStr += '\\s*}}';
+var partialsRE = new RegExp(partialsStr, 'g');
 
 // look for an opening mustache include tag, followed by >=0 whitespaces
 var partialsWithStyleModifiersStr = '{{>\\s*';
@@ -29,10 +46,10 @@ partialsWithStyleModifiersStr += '(?!\\()';
 // of alphanumerics, hyphens, and pipes
 partialsWithStyleModifiersStr += '(\\:[\\w\\-\\|]+)';
 
-// an optional group of characters starting with >=0 whitespaces, followed by
-// an opening parenthesis, followed by any number of characters that are not
-// closing parentheses, followed by a closing parenthesis
-partialsWithStyleModifiersStr += '(\\s*\\([^\\)]*\\))?';
+// an optional group of characters starting with >=0 whitespaces, followed by an
+// opening parenthesis, followed by a lazy match of non-whitespace or whitespace
+// characters (to include newlines), followed by a closing parenthesis
+partialsWithStyleModifiersStr += '(\\s*\\([\\S\\s]*?\\))?';
 
 // look for >=0 whitespaces, followed by closing mustache tag
 partialsWithStyleModifiersStr += '\\s*}}';
@@ -46,14 +63,13 @@ var partialsWithPatternParametersStr = '{{>\\s*';
 partialsWithPatternParametersStr += '([\\w\\-\\.\\/~]+)';
 
 // an optional group comprising a colon followed by one or more characters
-// comprising any combination of alphanumerics,
-// hyphens, and pipes
+// comprising any combination of alphanumerics, hyphens, and pipes
 partialsWithPatternParametersStr += '(\\:[\\w\\-\\|]+)?';
 
-// a group of characters starting with >=0 whitespaces, followed by an opening
-// parenthesis, followed by any number of characters that are not closing
-// parentheses, followed by a closing parenthesis
-partialsWithPatternParametersStr += '(\\s*\\([^\\)]*\\))';
+// a group of characters starting with >=0 whitespaces, followed by an
+// opening parenthesis, followed by a lazy match of non-whitespace or whitespace
+// characters (to include newlines), followed by a closing parenthesis
+partialsWithPatternParametersStr += '(\\s*\\([\\S\\s)]*?\\))';
 
 // look for >=0 whitespaces, followed by closing mustache tag
 partialsWithPatternParametersStr += '\\s*}}';
@@ -72,36 +88,11 @@ listItemsStr += '(one|two|three|four|five|six|seven|eight|nine|ten|eleven|twelve
 listItemsStr += '\\s*}}';
 var listItemsRE = new RegExp(listItemsStr, 'g');
 
-// look for an opening mustache loop tag, followed by >=0 whitespaces
-var partialKeyStr = '{{>\\s*';
-
-// one or more characters comprising any combination of alphanumerics,
-// hyphens, periods, slashses, and tildes
-partialKeyStr += '([\\w\\-\\.\\/~]+)';
-
-// an optional group of characters starting with a colon, followed by >0
-// alphanumerics, hyphens, or pipes
-partialKeyStr += '(\\:[\\w\\-|]+)?';
-
-// an optional group of characters starting with a colon, followed by >0
-// alphanumerics or hyphens
-partialKeyStr += '(\\:[\\w\\-]+)?';
-
-// an optional group of characters starting with >=0 whitespaces, followed by
-// an opening parenthesis, followed by any number of characters that are not
-// closing parentheses, followed by a closing parenthesis
-partialKeyStr += '(\\s*\\([^\\)]*\\))?';
-
-// look for >=0 whitespaces, followed by closing mustache tag
-partialKeyStr += '\\s*}}';
-var partialKeyRE = new RegExp(partialKeyStr, 'g');
-
 var utilMustache = {
   partialsRE: partialsRE,
   partialsWithStyleModifiersRE: partialsWithStyleModifiersRE,
   partialsWithPatternParametersRE: partialsWithPatternParametersRE,
-  listItemsRE: listItemsRE,
-  partialKeyRE: partialKeyRE
+  listItemsRE: listItemsRE
 };
 
 module.exports = utilMustache;