@Override
	public StringTree generate(RValInternal parent) {
		StringTree st = new StringTree();
		st.append(userop.getName());
		st.append("(");
		boolean first = false;
		for (RValInternal a : args) {
			if (!first) {
				first = true;
			}
			else {
				st.append(",");
			}
			st.append(a.generate(this));
		}
		st.append(")");
		return st;
	}
Build a call expression

@param ctx the context
@param userop the userop to invoke
@param args the arguments to pass in (by reference)
Ghidra/Features/SystemEmulation/src/main/java/ghidra/pcode/struct/CallExpr.java