<value> Class Reference

Methods in this pseudo-class are available to be executed on any value type (even NOTHING); this is the root class for all pseudo-classes. More...

Inheritance diagram for Qore::<value>:

Public Member Functions
bool	callp ()
	Returns False; this method is reimplemented in other types and will return True if the given expression is a callable value (ie closures or call references) More...
bool	empty ()
	Returns True; this method will be reimplemented in container types where it may return False. More...
bool	intp ()
	Returns False; this method is reimplemented in other types and will return True if the given expression can be converted to an integer. More...
AbstractIterator	iterator ()
	Returns an iterator object for the value; the default iterator object returned is SingleValueIterator. More...
int	lsize ()
	Returns 1; the return value of this method should give the list size of the value, which is normally 1 for non-lists (except for NOTHING where the size will be 0) and the number of the elements in the list for lists; this method will be reimplemented in other types where it may return other values. More...
int	size ()
	Returns zero; this method will be reimplemented in container types where it may return a non-zero value. More...
bool	sizep ()
	Returns True if the type can return a non-zero size (True for containers including binary objects and strings, False for everything else) More...
bool	strp ()
	Returns False; this method is reimplemented in other types and will return True if the given expression can be converted to a string. More...
bool	toBool ()
	Returns the boolean representation of the value; the default is False. More...
float	toFloat ()
	Returns the floating-point representation of the value; the default is 0.0. More...
int	toInt ()
	Returns the integer representation of the value; the default is 0. More...
number	toNumber ()
	Returns the arbitrary-precision numeric representation of the value; the default is 0. More...
string	toString ()
	Returns the string representation of the value; the default is an empty string. More...
string	type ()
	Returns the string type for the value. More...
int	typeCode ()
	Returns the type code for the value. More...
bool	val ()
	Returns False; this method is reimplemented in other types and will return True if the given expression has a value that would be converted to True according to the rules described in %perl-bool-eval. More...

Detailed Description

Methods in this pseudo-class are available to be executed on any value type (even NOTHING); this is the root class for all pseudo-classes.

Member Function Documentation

bool <value>::callp

(

)

Returns False; this method is reimplemented in other types and will return True if the given expression is a callable value (ie closures or call references)

Returns

False; this method is reimplemented in other types and will return True if the given expression is a callable value (ie closures or call references)

Code Flags:

CONSTANT

Example:

if ($n.callp())
    printf("the reuslt of calling the value: %y\n", $n());

bool <value>::empty

(

)

Returns True; this method will be reimplemented in container types where it may return False.

This pseudo-method will return False in all non-container types; use <value>::val() to check if a generic expression that might not be a container type has a value instead.

Returns

True; this method will be reimplemented in container types where it may return False

Code Flags:

CONSTANT

Example:

my int $i = 100;
if ($i.empty())
    printf("%y: is empty (probably because it's a value of type %y)\n", $i, $i.type());

See also

<value>::val()

bool <value>::intp

(

)

Returns False; this method is reimplemented in other types and will return True if the given expression can be converted to an integer.

Returns

False; this method is reimplemented in other types and will return True if the given expression can be converted to an integer

Code Flags:

CONSTANT

Example:

if ($n.intp())
    printf("%y: can be converted to an integer: %d\n", $n, int($n));

See also

<string>::intp() for an example of an implementation of this method where the result depends on the value and not the type

AbstractIterator <value>::iterator

(

)

Returns an iterator object for the value; the default iterator object returned is SingleValueIterator.

Returns

an iterator object for the value; the default iterator object returned is SingleValueIterator

Code Flags:

CONSTANT

Example:

map printf("+ %y\n", $1), $v.iterator();

Since

Qore 0.8.6

int <value>::lsize

(

)

Returns 1; the return value of this method should give the list size of the value, which is normally 1 for non-lists (except for NOTHING where the size will be 0) and the number of the elements in the list for lists; this method will be reimplemented in other types where it may return other values.

Returns

1; the return value of this method should give the list size of the value, which is normally 1 for non-lists (except for NOTHING where the size will be 0) and the number of the elements in the list for lists; this method will be reimplemented in other types where it may return other values

Code Flags:

CONSTANT

Example:

printf("iterating %d element%s\n", $val.lsize(), $val.lsize() == 1 ? "" : "s");
foreach my any $element in ($val) {
    do_something($element);
}

int <value>::size

(

)

Returns zero; this method will be reimplemented in container types where it may return a non-zero value.

This pseudo-method will return 0 in all non-container types; use <value>::val() to check if a generic expression that might not be a container type has a value instead.

Returns

zero; this method will be reimplemented in container types where it may return a non-zero value

Code Flags:

CONSTANT

Example:

my int $i = 100;
if (!$i.size())
    printf("%y: has size 0 (probably because it's a value of type %y)\n", $i, $i.type());

See also

• <value>::size()
• <value>::val()

bool <value>::sizep

(

)

Returns True if the type can return a non-zero size (True for containers including binary objects and strings, False for everything else)

Code Flags:

CONSTANT

Returns

True if the type can return a non-zero size (True for containers including binary objects and strings, False for everything else)

See also

<value>::size()

Since

Qore 0.8.9

bool <value>::strp

(

)

Returns False; this method is reimplemented in other types and will return True if the given expression can be converted to a string.

Returns

False; this method is reimplemented in other types and will return True if the given expression can be converted to a string

Code Flags:

CONSTANT

Example:

if ($n.strp())
    printf("%y: can be converted to a string: '%s'\n", $n, string($n));

bool <value>::toBool

(

)

Returns the boolean representation of the value; the default is False.

Code Flags:

CONSTANT

Returns

the boolean representation of the value; the default is False

Note

if <value>::intp() returns True, then the value can also be converted to a boolean value

Since

Qore 0.8.6

float <value>::toFloat

(

)

Returns the floating-point representation of the value; the default is 0.0.

Code Flags:

CONSTANT

Returns

the floating-point representation of the value; the default is 0.0

Note

if <value>::intp() returns True, then the value can also be converted to a floating-point value

Since

Qore 0.8.6

int <value>::toInt

(

)

Returns the integer representation of the value; the default is 0.

Code Flags:

CONSTANT

Use <value>::intp() to determine if the current value can be converted to an integer

Returns

the integer representation of the value; the default is 0

Since

Qore 0.8.6

number <value>::toNumber

(

)

Returns the arbitrary-precision numeric representation of the value; the default is 0.

Code Flags:

CONSTANT

Returns

the integer representation of the value; the default is 0

Note

if <value>::intp() returns True, then the value can also be converted to an arbitrary-precision numeric value

Since

Qore 0.8.8

string <value>::toString

(

)

Returns the string representation of the value; the default is an empty string.

Code Flags:

CONSTANT

Use <value>::strp() to determine if the current value can be converted to a string

Returns

the string representation of the value; the default is an empty string

Note

check pseudo-classes for each type for other variants of this method; some may take arguments to affect the output format

Since

Qore 0.8.6

string <value>::type

(

)

Returns the string type for the value.

Returns

the string type for the value; see String Type Constants for possible return values for each type

Code Flags:

CONSTANT

Example:

my string $t = $n.type();

Note

It is faster and more efficient to use <value>::typeCode() for comparing data types

int <value>::typeCode

(

)

Returns the type code for the value.

This method is recommended over <value>::type() or the type(any) or typename(any) functions for comparing data types as it is much faster and more efficient than the other alternatives (which work with string values instead of integer codes).

Returns

the type code for the value; see Type Code Constants for possible return values for each type

Code Flags:

CONSTANT

Example:

switch ($v.typeCode()) {
    case NT_INT:
        printf("%y: is an integer\n", $v);
        break;

    case NT_DATE:
        printf("%y: is a date\n", $v);
        break;

    default:
        printf("%y: is something else entirely\n", $v);
        break;
}

bool <value>::val

(

)

Returns False; this method is reimplemented in other types and will return True if the given expression has a value that would be converted to True according to the rules described in %perl-bool-eval.

This pseudo-method can be used to mimic perl's boolean evaluation when %strict-bool-eval is enabled; the return value of this method is the same as that of any value when evaluated in a boolean context when %perl-bool-eval is enabled (the default).

Prior to version 0.8.6, Qore implemented strict mathematical boolean evaluation by default (where any value must evaluate to a non-zero integer or floating-point value to be True), so this pseudo-method was implemented to provide the same functionality in qore. Note that as of qore 0.8.6, %perl-bool-eval is the default.

Returns

False; this method is reimplemented in other types and will return True if the given expression has a value; the return value of this method is the same as that of any value when evaluated in a boolean context when %perl-bool-eval is enabled (the default)

Code Flags:

CONSTANT

Example:

if ($n.val())
    printf("%y: has a value\n", $n);

Note

use Exists Operator (exists) to tell if an expression has a value or not

See also

• %perl-bool-eval
• %strict-bool-eval