private boolean isDataTypeNameCharacter(char ch) {

		/*
			Note: really, this should just be checking a list of known disallowed characters,
				  which is something like:
		
				  <,>,(,),&,*,[,]
		
		 		  It seems like the current code below is unnecessarily restrictive
		 */

		//@formatter:off
		return Character.isLetter(ch) ||
			   Character.isDigit(ch) ||
			   ch == ':' ||
			   ch == '_' ||
			   ch == '{' ||
			   ch == '$';
		//@formatter:on
	}
This method converts each parameter string into
actual DemangledDataType objects.
Ghidra/Features/GnuDemangler/src/main/java/ghidra/app/util/demangler/gnu/GnuDemanglerParser.java