27 Apr
                
                    2010
                
            
            
                27 Apr
                
                '10
                
            
            
            
        
    
                4:12 p.m.
            
        So UU parsers can construct input? The presence of an empty list in the 2nd slot of the tuple is the only indicator of errors? For parsing datatypes without a sensible default value, what happens? -- Jason Dusek