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26  const standard library

The const module provides fundamental mathematical, geometric, integer limit, and IEEE 754 floating-point constants. Because const has no foreign libm bindings, it can be imported freely in standalone and WebAssembly (wasm32-unknown-unknown) modules alongside % compiler intrinsics without linking -lm.

#use const

26.1 Mathematical Constants (Float)

Constant Type Value Description
const::pi Float 3.14159265358979323846 Archimedes’ constant \(\pi\)
const::tau Float 6.28318530717958647692 Circle constant \(\tau = 2\pi\)
const::e Float 2.71828182845904523536 Euler’s number \(e\)
const::phi Float 1.61803398874989484820 Golden ratio \(\phi = (1 + \sqrt{5}) / 2\)
const::inv_phi Float 0.61803398874989484820 Inverse golden ratio \(1/\phi = \phi - 1\)
const::sqrt2 Float 1.41421356237309504880 Square root of 2 \(\sqrt{2}\)
const::sqrt3 Float 1.73205080756887729352 Square root of 3 \(\sqrt{3}\)
const::ln2 Float 0.69314718055994530942 Natural logarithm of 2 \(\ln(2)\)
const::ln10 Float 2.30258509299404568402 Natural logarithm of 10 \(\ln(10)\)

26.2 Integer Limits

Constant Type Value Description
const::max_i64 Int (i64) 9223372036854775807 Maximum signed 64-bit integer
const::min_i64 Int (i64) -9223372036854775808 Minimum signed 64-bit integer
const::max_i32 i32 2147483647i32 Maximum signed 32-bit integer
const::min_i32 i32 -2147483648i32 Minimum signed 32-bit integer
const::max_i16 i16 32767i16 Maximum signed 16-bit integer
const::min_i16 i16 -32768i16 Minimum signed 16-bit integer
const::max_i8 i8 127i8 Maximum signed 8-bit integer
const::min_i8 i8 -128i8 Minimum signed 8-bit integer
const::max_u64 u64 18446744073709551615u64 Maximum unsigned 64-bit integer
const::max_u32 u32 4294967295u32 Maximum unsigned 32-bit integer
const::max_u16 u16 65535u16 Maximum unsigned 16-bit integer
const::max_u8 u8 255u8 Maximum unsigned 8-bit integer

26.3 Floating-Point Limits & IEEE-754 Constants

Use unary - for negative infinity (-const::inf_f64, -const::inf_f32) and most negative finite values (-const::max_f64, -const::max_f32). Signed negative zero is written directly as -0.0 or -0.0f32.

Constant Type IEEE-754 Bit Pattern Description
const::inf_f64 Float (f64) 0x7ff0000000000000 Positive infinity (\(+\infty\))
const::nan_f64 Float (f64) 0x7ff8000000000000 Quiet NaN
const::max_f64 Float (f64) 0x7fefffffffffffff Largest finite f64 (1.7976931348623157e+308)
const::min_f64 Float (f64) 0x0010000000000000 Smallest positive normal f64 (2.2250738585072014e-308)
const::sub_f64 Float (f64) 0x0000000000000001 Smallest positive subnormal f64 (5e-324)
const::eps_f64 Float (f64) 0x3cb0000000000000 Machine epsilon for f64 (\(2^{-52} \approx 2.220446049250313\times 10^{-16}\))
const::inf_f32 f32 0x7f800000u32 Positive infinity (\(+\infty\))
const::nan_f32 f32 0x7fc00000u32 Quiet NaN
const::max_f32 f32 0x7f7fffffu32 Largest finite f32 (3.4028235e+38f32)
const::min_f32 f32 0x00800000u32 Smallest positive normal f32 (1.1754944e-38f32)
const::sub_f32 f32 0x00000001u32 Smallest positive subnormal f32 (1.4012985e-45f32)
const::eps_f32 f32 0x34000000u32 Machine epsilon for f32 (\(2^{-23} \approx 1.1920929\times 10^{-7}\)) 
#use const
#use io

io::out(const::tau / const::pi)
// => 2