collections Range - tadashi9e/gmp4pony GitHub Wiki

Range[optional A: (Real[A] val & (I8 val | I16 val | I32 val | I64 val | I128 val | ILong val | ISize val | U8 val | U16 val | U32 val | U64 val | U128 val | ULong val | USize val | F32 val | F64 val))]

[Source]

Produces [min, max) with a step of inc for any Number type.

// iterating with for-loop
for i in Range(0, 10) do
  env.out.print(i.string())
end

// iterating over Range of U8 with while-loop
let range = Range[U8](5, 100, 5)
while range.has_next() do
  try
    handle_u8(range.next()?)
  end
end

Supports min being smaller than max with negative inc but only for signed integer types and floats:

var previous = 11
for left in Range[I64](10, -5, -1) do
  if not (left < previous) then
    error
  end
  previous = left
end

If the step is not moving min towards max or if it is 0, the Range is considered infinite and iterating over it will never terminate:

let infinite_range1 = Range(0, 1, 0)
infinite_range1.is_infinite() == true

let infinite_range2 = Range[I8](0, 10, -1)
for _ in infinite_range2 do
  env.out.print("will this ever end?")
  env.err.print("no, never!")
end

When using Range with floating point types (F32 and F64) inc steps < 1.0 are possible. If any of the arguments contains NaN, +Inf or -Inf the range is considered infinite as operations on any of them won't move min towards max. The actual values produced by such a Range are determined by what IEEE 754 defines as the result of min + inc:

for and_a_half in Range[F64](0.5, 100) do
  handle_half(and_a_half)
end

// this Range will produce 0 at first, then infinitely NaN
let nan: F64 = F64(0) / F64(0)
for what_am_i in Range[F64](0, 1000, nan) do
  wild_guess(what_am_i)
end
class ref Range[optional A: (Real[A] val & (I8 val | I16 val | I32 val | 
    I64 val | I128 val | ILong val | 
    ISize val | U8 val | U16 val | 
    U32 val | U64 val | U128 val | 
    ULong val | USize val | F32 val | 
    F64 val))] is
  Iterator[A] ref

Implements

Constructors

create

[Source]

new ref create(
  min: A,
  max: A,
  inc: A = 1)
: Range[A] ref^

Parameters

  • min: A
  • max: A
  • inc: A = 1

Returns

Public Functions

has_next

[Source]

fun box has_next()
: Bool val

Returns

next

[Source]

fun ref next()
: A ?

Returns

  • A ?

rewind

[Source]

fun ref rewind()
: None val

Returns

is_infinite

[Source]

fun box is_infinite()
: Bool val

Returns

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