I was playing around with a PEG parser to do what you wanted (and may post that as a separate answer later) when I noticed that there's a very simple algorithm that does a remarkably good job with common forms of numbers in English, Spanish, and German, at the very least.
Working with English for example, you need a dictionary that maps words to values in the obvious way:
"one" -> 1, "two" -> 2, ... "twenty" -> 20,
"dozen" -> 12, "score" -> 20, ...
"hundred" -> 100, "thousand" -> 1000, "million" -> 1000000
...and so forth
The algorithm is just:
total = 0
prior = null
for each word w
v <- value(w) or next if no value defined
prior <- case
when prior is null: v
when prior > v: prior+v
else prior*v
else
if w in {thousand,million,billion,trillion...}
total <- total + prior
prior <- null
total = total + prior unless prior is null
For example, this progresses as follows:
total prior v unconsumed string
0 _ four score and seven
4 score and seven
0 4
20 and seven
0 80
_ seven
0 80
7
0 87
87
total prior v unconsumed string
0 _ two million four hundred twelve thousand eight hundred seven
2 million four hundred twelve thousand eight hundred seven
0 2
1000000 four hundred twelve thousand eight hundred seven
2000000 _
4 hundred twelve thousand eight hundred seven
2000000 4
100 twelve thousand eight hundred seven
2000000 400
12 thousand eight hundred seven
2000000 412
1000 eight hundred seven
2000000 412000
1000 eight hundred seven
2412000 _
8 hundred seven
2412000 8
100 seven
2412000 800
7
2412000 807
2412807
And so on. I'm not saying it's perfect, but for a quick and dirty it does quite well.
Addressing your specific list on edit:
- cardinal/nominal or ordinal: "one" and "first" -- just put them in the dictionary
- english/british: "fourty"/"forty" -- ditto
- hundreds/thousands:
2100 -> "twenty one hundred" and also "two thousand and one hundred" -- works as is
- separators: "eleven hundred fifty two", but also "elevenhundred fiftytwo" or "eleven-hundred fifty-two" and whatnot -- just define "next word" to be the longest prefix that matches a defined word, or up to the next non-word if none do, for a start
- colloqialisms: "thirty-something" -- works
- fragments: 'one third', 'two fifths' -- uh, not yet...
- common names: 'a dozen', 'half' -- works; you can even do things like "a half dozen"
Number 6 is the only one I don't have a ready answer for, and that's because of the ambiguity between ordinals and fractions (in English at least) added to the fact that my last cup of coffee was many hours ago.
If the .rav is not embedded in the executable (yes, it's possible), you can modify the dataview and substitute the original ones to direct database dataviews. So, you can modify the report if the program just fire the report without further parametrization...... There is some documentation on the script engine of rave, in the help of visual editor and in the Nevrona site.
Of course, Nevrona needs to do better documentation...
Best Answer
I do not think Rave Reports has any inbuilt function which converts numbers to works. However, I have found a article, which explains How to Convert Numbers (Currency) to Words, on About.com.
Have a look at the ConvertToWords function in the NumberToWords unit.
You could convert the number and pass the words to the report at runtime.
Edit:
You can pass parameters to your reports like this.
Have a look at the Introduction to Rave Reports article.