NAME
    sum - sum, or sum of defined sums

SYNOPSIS
    sum(x_1, x_2, ...)

TYPES
    x_1, x_2, ...	any

    return		any

DESCRIPTION
    If an argument x_i is a list with elements e_1, e_2, ..., e_n, it
    is treated as if x_i were replaced by e_1, e_2, ..., e_n; this may
    continue recurively if any of the e_j is a list.

    If an argument x_i is an object of type xx, then x_i is replaced by
    xx_sum(x_i) if the function xx_sum() has been defined.  If the
    type xx has been defined by:

		obj xx = {x, y, z},

    an appropriate definition of xx_sum(a) is sometimes a.x + a.y + a.z.
    sum(a) then returns the sum of the elements of a.

    If x_i has the null value, it is ignored.  Thus, sum(a, , b, , c)
    will return the same as sum(a, b, c).

    Assuming the above replacements, and that the x_1, x_2, ..., are
    of types for which addition is defined, sum(x_1, x_2, ...) returns
    the sum of the arguments.

EXAMPLE
    ; print sum(2), sum(5, 3, 7, 2, 9), sum(3.2, -0.5, 8.7, -1.2, 2.5)
    2 26 12.7

    ; print sum(list(3,5), 7, list(6, list(7,8), 2))
    38


    ; obj point {x, y}
    ; define point_add(a,b) = obj point = {a.x + b.x, a.y + b.y}
    ; obj point A = {1, 5}
    ; obj point B = {1, 4}
    ; obj point C = {3, 3}
    ; print sum(A, B, C)
    obj point {5, 12}

    ; define point_sum(a) = a.x
    ; print sum(A, B, C)
    5

LIMITS
    The number of arguments is not to exceed 1024.

LINK LIBRARY

SEE ALSO
    max, min, obj, ssq

## Copyright (C) 1999-2006  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
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## 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
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## Under source code control:	1997/03/10 03:59:59
## File existed as early as:	1997
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