overloading
display, functions and operators overloading capabilities
Description
In Scilab, variable display, functions and operators may be defined for new objects using functions (Scilab coded or primitives).
 Display
The display of new objects defined by
tlist
structure may be overloaded (the default display is similar tolist
's one). The overloading function must have no output argument and a single input argument. It's name is formed as follow%<tlist_type>_p
where%<tlist_type>
stands for the first entry of thetlist
type component truncated to the first 9 characters. Operators
Each operator which is not defined for given operands type may be defined. The overloading function must have a single output argument and one or two inputs according to the number of operands. The function name is formed as follow:
for binary operators:
%<first_operand_type>_<op_code>_<second_operand_type>
;
for unary operators:
%<operand_type>_<op_code>
;
extraction and insertion operators which are nnary operators are described below.
Be careful, only the types registered by the
typename function can be used in an overloading
macros. 
<operand_type>
,
<first_operand_type>
,
<second_operand_type>
are sequence of characters
associated with each data type as described in the following table:
data type  char code  typeof  comments 
double matrix  s 
constant 

polynomial matrix  p 
polynomial 

boolean matrix  b 
boolean 

sparse matrix  sp 
sparse 

boolean sparse matrix  spb 
boolean sparse 

Matlab sparse matrix  msp 
Matlab sparse 

integer matrix  i 
int8, int16, int32, int64, uint8, uint16, uint32, uint64 

string matrix  c 
string 

handle  h 
handle 

hardcoded function  fptr 
fptr 

script function  function 
function 

library  f 
library 

list  l 
list 

tlist  tlist type 
tlist type 
the first string in the first tlist entry 
mlist  mlist type 
mlist type 
the first string in the first mlist entry 
pointer  ptr 
pointer 

cell  ce 
ce 

structure  st 
st 

rational  r 
rational 

linear state space  lss 
statespace 

implicit list  ip 
implicitlist 
1:1:$ 
undefinednull object  0 
listdelete, void 
see null(), list() 
<op_code>
is a single character associated
with each operator as described in the following table:
op 
char code 
' 
t 
+ 
a 
 
s 
* 
m 
/ 
r 
\ 
l 
^ 
p 
.* 
x 
./ 
d 
.\ 
q 
.*. 
k 
./. 
y 
.\. 
z 
: 
b 
*. 
u 
/. 
v 
\. 
w 
[a,b] 
c 
[a;b] 
f 
() extraction 
e 
() insertion 
i 
== 
o 
<> 
n 
 
g 
& 
h 
.^ 
j 
.' 
0 
< 
1 
> 
2 
<= 
3 
>= 
4 
~ 
5 
iext 
6 
The overloading function for extraction syntax b= a(i1,
..., in)
has the following syntax: b =
%<type_of_a>_e(i1, ..., in, a)
and the syntax [x1, .., xm] = a(i1, ..., in)
has
the following syntax: [x1, .., xm] =
%<type_of_a>_e(i1, ..., in, a)
.
The overloading function associated to the insertion syntax
a(i1, ..., in) = b
has the following syntax:
a = %<type_of_b>_i_<type_of_a>(i1, ..., in, b,
a)
.
The 6
char code may be used for some complex
insertion algorithm like x.b(2) = 33
where
b
field is not defined in the structure
x
. The insertion is automatically decomposed into
temp = x.b
; temp(2) = 33
;
x.b = temp
. The 6
char code is used
for the first step of this algorithm. The 6
overloading
function is very similar to the e
's one.
 Functions :
Some basic primitive function may also be overloaded for new data type. When such function is undefined for a particular data types the function
%<type_of_an_argument>_<function_name>
is called. User may add in this called function the definition associated with the input data types.
Examples
//OPERATOR 's' + 1 // it is impossible to add a number to a string function x=%c_a_s(a, b) x = a + string(b); endfunction 's' + 1 // after overloading
See also
History
Version  Description 
6.0 

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