Parsing numbers September 6, 2008 After some thought, here is a strategy for parsing numbers. Step 1: Word mappings and entity types The following word mappings and entity types are required: 'one' -> 1: digit 'two' -> 2: digit 'three' -> 3: digit 'four' -> 4: digit 'five' -> 5: digit 'six' -> 6: digit 'seven' -> 7: digit 'eight' -> 8: digit 'nine' -> 9: digit 'eleven' -> 11: teen_number 'twelve' -> 12: teen_number 'thirteen' -> 13: teen_number 'fourteen' -> 14: teen_number 'fifteen' -> 15: teen_number 'sixteen' -> 16: teen_number 'seventeen' -> 17: teen_number 'eighteen' -> 18: teen_number 'nineteen' -> 19: teen_number 'twenty' -> 20: group_of_ten 'thirty' -> 30: group_of_ten 'forty' -> 40: group_of_ten 'fifty' -> 50: group_of_ten 'sixty' -> 60: group_of_ten 'seventy' -> 70: group_of_ten 'eighty' -> 80: group_of_ten 'ninety' -> 90: group_of_ten 'hundred' -> 100: multiplier 'thousand' -> 1000: multiplier 'million' -> 1000000: multiplier 'billion' -> 1000000000: multiplier 'trillion' -> 1000000000000: multiplier 'quadrillion' -> 1000000000000000: multiplier number_part digit is_a number_part teen_number is_a number_part group_of_ten is_a number_part 100+_number_part is_a number_part 100+_number_part is_a number Step 2: New transformation type The first step is to introduce a new transformation type which evaluates a numerical formula. For example: {group_of_ten} {digit} -> # $1 + $2 The # prefix indicates that the transformation's output specification is a numeric formula. In addition, it would be helpful to be able to specify as a part of any transformation, what the result's entity type should be considered. For example: {group_of_ten} {digit} -> # $1 + $2 (number_part) Step 3: Transformations {group_of_ten} {digit} -> # $1 + $2 (number_part) {number_part} {multiplier} -> # $1 * $2 (100+_number_part) {multiplier} {number_part} -> # $1 + $2 (100+_number_part) {100+_number_part} {100+_number_part} -> # $1 + $2 (100+_number_part) {100+_number_part} {number_part} -> # $1 + $2 {100+_number_part} and {number_part} -> # $1 + $2 {number} + {number} -> # $1 + $2 {number} * {number} -> # $1 * $2