1. Pointers
What is all this jazz about pointers? The whole point of Euphoria
programming is that it is simple and fast. Throw pointers into the mix
and you just killed half of Euphoria! If you want stuff like that take
up C :) The simplicity of BASIC, the speed of a compiled language, and
[with some of the new memory routines in ver 1.5] the power of C. That
is what Euphoria is all about !!!
2. Re: Pointers
-- With all the talk of pointers, the following may save someone some
--trouble. Bottom line, in a numerical sequence, the storage space is
--somewhar unpredictable...so forget about pointer arithmetic.
-- A small demo prog follows showing the bytes per term may change
--unexpectdly as the data varies from float to float auto converted to
--integer whae possible.
--Demo for size of a numeric sequence.
--include bytes.e
--This handy bytes.e came from Rob Craig. It estimates the # of bytes needed
--by an object. I have found it useful.
--Bytes.e
global function bytes(object x)
-- estimates the number of bytes of storage needed for any
-- Euphoria 2.0 data object (atom or sequence).
integer space
if integer(x) then
return 4
elsif atom(x) then
return 16
else
-- sequence
space = 24 -- overhead
for i = 1 to length(x) do
space = space + bytes(x[i])
end for
return space
end if
end function
-->integer int
-->int = 1
--? bytes_needed(1) -- 4
--? bytes_needed(1.5) -- 16
--? bytes_needed({1,2,3}) -- 36
--? bytes_needed({{1.5,2.5}, {1,2}}) -- 112
--? bytes_needed({{1,2},{}, {}, {1,2}}) -- 88 , 112, 136
--? bytes_needed(int)
--END bytes.e
--Make a seq of floats with howMany elements
sequence seq1
integer howMany
howMany = 10
seq1 = repeat(1.1, howMany)
--Set values all different
for i = 1 to howMany by 1 do
seq1[i] = seq1[i] * i
end for
? bytes(howMany) --IE, an integer uses 4 bytes
? bytes(1.1) --IE, a float uses 16 bytes
? bytes(seq1) --A seq uses 24 + 4 per integer + 16 per float
? seq1 --Note, autoconversion to integer for term 10
? (bytes(seq1) - 24) / howMany --IE, a numerical seq length is not predictable
--just a check
? integer(seq1[9])
? integer(seq1[10])
--Pointer arithmetic for a numeric sequence not a good idea.
--Arthur P. Adamson, The Engine Man, euclid at isoc.net
