overloading

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 to list's one). The overloading function must have no output argument a single input argument. It's name is formed as follow %<tlist_type>_p where %<tlist_type> stands for the first entry of the tlist 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 n-nary 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, uint8, uint16, uint32`
string matrix	`s`	`string`
handle	`h`	`handle`
compiled function	`fptr`	`fptr`
script function	`function`	`mc`
library	`library`	`f`
list	`list`	`l`
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
hypermatrix	`hypermat`	`hm`
pointer	`pointer`	`ptr`

<op_code> is a single character associated with each operator as described in the following table:

op	char code	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
~	5	.'	0
<	1	>	2
<=	3	>=	4
		iext	6

The overloading function for extraction syntax b=a(i1,...,in) has the following calling sequence: b=%<type_of_a>_e_(i1,...,in,a)

and the syntax [x1,..,xm]=a(i1,...,in) has the following calling sequence: [x1,..,xm]=%<type_of_a>_e_(i1,...,in,a)

The overloading function associated to the insertion syntax a(i1,...,in)=b has the following calling sequence: 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 a 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

 
//DISPLAY
deff('[]=%tab_p(l)','disp([['' '';l(3)] [l(2);string(l(4))]])')
tlist('tab',['a','b'],['x';'y'],rand(2,2))

//OPERATOR
deff('x=%c_a_s(a,b)','x=a+string(b)')
's'+1

//FUNCTION
deff('x=%c_sin(a)','x=''sin(''+a+'')''')
sin('2*x')

Name

Description

Examples

See Also