Percentage calculations

[lehnen]

Hy Chris,

I try to implement a percentage calculation in form of:
20 + 19% that should result in 23.8 or
45 * 10% that should result in 202.5
For the first one you could also state 20 * 1.19, but the users are more familiar to the first way.

As I can see, the calculator can be extended, but operators always follow the form x [operator] y.

Do you see a way how I can implement this with the AbstractSymbol API?

Greetings from Germany
Volker

[chriskonnertz]

Hello,

I try to implement a percentage calculation in form of: 20 + 19% that should result in 23.8

well, good luck. 😉

20 + 19% is the same as (20 + 19%) wich is the same as (20 * 1.19)

Okay, let's ignore the brackets for know, so we assume 20 + 19% is exactly the same as 20 * 1.19.
So we could say that the + operator is transformed into *.
Unfortunately, in the current implementation operators always operate on numbers.
How could the plus operator (class) decide when it has to do a conventional addition and when to do a multiplication instead? Right know I do not have an answer.
But this is just straight forward thinking, maybe there are other ways.

45 * 10% that should result in 202.5

I guess that should be possible when allowing unary operators to be in postfix notation.
I need some time to figure out how to do that (haven't spent much time with StringCalc lately).

[lehnen]

Thx a lot. Would be great.
I will try some ideas also.