Add support for arbitrary-length numbers

[NhanAZ]

$parser = Parser::createDefault();

$expression = $parser->parse("111111111111111111111111111111111111111111111111111111111111111111111111111");
var_dump($expression->evaluate()); // int(9223372036854775807)

$expression = $parser->parse("111111111111111111111111111111111111111111111");
var_dump($expression->evaluate()); // int(9223372036854775807)

$expression = $parser->parse("99999999999999999999999");
var_dump($expression->evaluate()); // int(9223372036854775807)

$expression = $parser->parse("9999999999999999999999999999999999");
var_dump($expression->evaluate()); // int(9223372036854775807)

[NhanAZ]

$parser = Parser::createDefault();

$expression = $parser->parse("--1 + 1");
var_dump($expression->evaluate());
// Expect: int(2)
// Result: Error: Unexpected token encountered at (1:5) "-1+1" when parsing "--1+1"

[Muqsit]

$parser = Parser::createDefault();

$expression = $parser->parse("111111111111111111111111111111111111111111111111111111111111111111111111111");
var_dump($expression->evaluate()); // int(9223372036854775807)

$expression = $parser->parse("111111111111111111111111111111111111111111111");
var_dump($expression->evaluate()); // int(9223372036854775807)

$expression = $parser->parse("99999999999999999999999");
var_dump($expression->evaluate()); // int(9223372036854775807)

$expression = $parser->parse("9999999999999999999999999999999999");
var_dump($expression->evaluate()); // int(9223372036854775807)

9223372036854775807 resolves to PHP_INT_MAX (on 32-bit computers, this value is 2147483648). Calculators usually throw an "Invalid Input" value when something like this occurs. This could be solved using something such as bcmath but this would make Expression::evaluate() yield a (string) value type and cause an inconsistency in return type based on number range.

$parser = Parser::createDefault();

$expression = $parser->parse("--1 + 1");
var_dump($expression->evaluate());
// Expect: int(2)
// Result: Error: Unexpected token encountered at (1:5) "-1+1" when parsing "--1+1"

--1 + 1 is an invalid expression in PHP and generally in calculators as well, -(-1) + 1 works, -+-1 works as well.

[NhanAZ]

i think --1+1 is an invalid expression in PHP but on calculator it's valid...
I tested it on Casio scientific calculators and it works

[NhanAZ]

For "Invalid Input" I think it should throw an error instead of returning PHP_INT_MAX
(Accurate results should still be preferred instead of throwing an error)

[Muqsit]

For "Invalid Input" I think it should throw an error instead of returning PHP_INT_MAX (Accurate results should still be preferred instead of throwing an error)

IMO, devs should consider checking for bounds for their application as capping at INT_MIN/MAX is expected behaviour among various programming languages.

[Muqsit]

One way to support arbitrary-length integers would be by having a separate Parser::createBcMath() that uses bcmath during unary/binary operations, and Parser::createGmp() that uses GMP instead.
But since these extensions return a string or a custom object containing the number:

bcadd(string $num1, string $num2, ?int $scale = null): string
gmp_abs(GMP|int|string $num): GMP

they would interfere with functions such as sin(), cos(), tan(), pow() etc. that accept a number as their input. GMP has a gmp_pow() function but does not have its own functions for trigonometry or many of the other PHP math functions. Each parser (Parser::createDefault(), Parser::createBcMath(), and Parser::createGmp()) would have different sets of available functions.

[NhanAZ]

int + int = int

$parser = Parser::createDefault();
$expression = $parser->parse("9223372036854775807 - 1 + 1");
var_dump($expression->evaluate()); // int(9223372036854775807)

same expression but int + int = float

$parser = Parser::createDefault();
$expression = $parser->parse("9223372036854775807 + 1 - 1");
var_dump($expression->evaluate()); // float(9.223372036854776E+18)

[Muqsit]

int + int = int

$parser = Parser::createDefault();
$expression = $parser->parse("9223372036854775807 - 1 + 1");
var_dump($expression->evaluate()); // int(9223372036854775807)

same expression but int + int = float

$parser = Parser::createDefault();
$expression = $parser->parse("9223372036854775807 + 1 - 1");
var_dump($expression->evaluate()); // float(9.223372036854776E+18)

That is expected behaviour as well according to how PHP performs the operation.
https://3v4l.org/vlom6#v8.1.11