ION supports many of PHP's data types:
Additonally to the plain and simple NULL, ION can attach a type to NULL values.
<?php
$writer = new ion\Writer\Stream\Writer(STDOUT);
$writer->writeNull();
$writer->writeTypedNull(ion\Type::Int);
$writer->writeTypedNull(ion\Type::String);
$writer->flush();
/*
null
null.int
null.string
*/
?>
The bool type does not need a lot of explanation:
<?php
$writer->writeBool(true);
$writer->writeBool(false);
$writer->flush();
/*
true
false
*/
?>
The int type comprises signed integers of arbitrary size.
<?php
$writer->writeInt(123);
$writer->writeInt("12345678901234567890");
$writer->flush();
/*
123
12345678901234567890
*/
?>
In ION-Text, underscores are allowed to separate digits:
<?php
$reader = new ion\Reader\Buffer\Reader("-123_456_789");
$reader->next();
var_dump($reader->getType());
var_dump($reader->readInt());
/*
enum(ion\Type::Int)
int(-123456789)
*/
?>
Hexadecimal as well as binary notation are supported, too:
<?php
$reader = new ion\Reader\Buffer\Reader("0xdead_beef");
$reader->next();
var_dump($reader->readInt());
/*
int(3735928559)
*/
$reader = new ion\Reader\Buffer\Reader("0b10000100_11001001");
$reader->next();
var_dump($reader->readInt());
/*
int(33993)
*/
?>
Ion supports both binary and lossless decimal encodings of real numbers as, respectively, types float and decimal. In the text format, float values are denoted much like the decimal formats in C or Java; decimal values use d instead of e to start the exponent.
Reals without an exponent are treated as decimal. As with JSON, extra leading zeros are not allowed. Digits may be separated with an underscore.
<?php
var_dump(ion\serialize(0.123));
/*
string(25) "0.12299999999999999822e+0"
*/
var_dump(ion\unserialize("[0.123e, 123e-3]"));
/*
array(2) {
[0]=>
float(0.123)
[1]=>
float(0.123)
}
*/
?>
<?php
var_dump(ion\serialize(new ion\Decimal("0.123")));
/*
string(5) "0.123"
*/
var_dump(ion\unserialize("[0.123d0, 123d-3]"));
/*
array(2) {
[0]=>
object(ion\Decimal)#8 (2) {
["number"]=>
string(5) "0.123"
// ...
}
[1]=>
object(ion\Decimal)#11 (2) {
["number"]=>
string(5) "0.123"
// ...
}
}
*/
?>
Ion strings are Unicode character sequences of arbitrary length.
In the text format, strings are delimited by double-quotes and follow common backslash-escape conventions (see official spec). The binary format always uses UTF-8 encoding.
<?=
ion\serialize([
"abc", "new
line"
]);
/*
["abc", "new\nline"]
*/
?>
The text format supports an alternate syntax for “long strings”, including those that break across lines. Sequences bounded by three single-quotes (''') can cross multiple lines and still count as a valid, single string. In addition, any number of adjacent triple-quoted strings are concatenated into a single value.
The concatenation happens within the Ion text parser and is neither detectable via the data model nor applicable to the binary format. Note that comments are always treated as whitespace, so concatenation still occurs when a comment falls between two long strings.
<?php
var_dump(ion\unserialize("
'''
here are
several new
lines
'''
"));
/*
string(35) "
here are
several new
lines
"
*/
?>
Ion defines three container types: structures, lists, and S-expressions. These types are defined recursively and may contain values of any Ion type.
Lists are ordered collections of values. The contents of the list are heterogeneous (that is, each element can have a different type). In the text format, lists are bounded by square brackets and elements are separated by commas.
<?=
ion\serialize([1, "yes", null]);
/*
[1,"yes",null]
*/
?>
Structures are unordered collections of name/value pairs. The names are symbol tokens, and the values are unrestricted. Each name/value pair is called a field.
In the text format, structures are wrapped by curly braces, with a colon between each name and value, and a comma between the fields. For the purposes of JSON compatibility, it’s also legal to use strings for field names, but they are converted to symbol tokens by the parser.
<?=
ion\serialize([
"outlaw",
"key" => "value",
"obj" => (object)["key" => "value"]
]);
/*
{'0':"outlaw",key:"value",obj:o::{key:"value"}}
*/
?>
<?php
var_dump(ion\unserialize(
'{\'0\':"outlaw",key:"value",obj:o::{key:"value"}}'
));
/*
array(3) {
[0]=>
string(6) "outlaw"
["key"]=>
string(5) "value"
["obj"]=>
object(stdClass)#10 (1) {
["key"]=>
string(5) "value"
}
}
*/
?>