It will be a general purpose text based calculator/calculator component written in Delphi.

Users can define variables and functions. Functions can be defined in 2 ways:

  1. with a minimal functional language (inspired by Haskell) built in Kalkar. Examples:
    fact n = if n == 0 then 1 else fact (n-1)
    sum List = if empty List then 0 else head List + sum Tail List
    SomeList = 1,2,3
    sum (SomeList, 4, 5) - (2^2)
    last line would print 11

  2. with any external programming language which is able to read input (arguments) from command-line and to print answer on stdout. If user uses some function not defined in Kalkar, then Kalkar looks for a script with same name from a designated folder, runs it with arguments and reads output.
Something is already done -- simple expressions and defining variables and lists and exernal functions. And there is an user interface for it.



Input       -> List
List        -> Sum [, List]
Sum         -> Term {('+'|'-') Term}
Term        -> Factor {('*'|'/') Factor}
Factor      -> SignedStuff ['^' Factor]
SignedStuff -> {('-'|'/')} Stuff
Stuff       -> ( posnum | Ident | '(' [List] ')' )
Ident       -> name [Stuff | '=' List]
'/' on the line of SignedStuff is unary division operator: '/2' means '1/2'. It's good for constructing root operator '^/' so you can write '4^/2' instead of '4^(1/2)'

Variables holding lists and functions returning lists must begin with uppercase letter.

Download current work from download page
Code is also available from Subversion repository (info here)
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