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range.go
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range.go
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package vm
import (
"fmt"
"github.com/goby-lang/goby/vm/classes"
"github.com/goby-lang/goby/vm/errors"
)
// RangeObject is the built in range class
// Range represents an interval: a set of values from the beginning to the end specified.
// Currently, only Integer objects or integer literal are supported.
//
// ```ruby
// r = 0
// (1..(1+4)).each do |i|
// puts(r = r + i)
// end
// ```
//
// ```ruby
// r = 0
// a = 1
// b = 5
// (a..b).each do |i|
// r = r + i
// end
// ```
//
type RangeObject struct {
*baseObj
Start int
End int
}
// Class methods --------------------------------------------------------
func builtinRangeClassMethods() []*BuiltinMethodObject {
return []*BuiltinMethodObject{
{
Name: "new",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
return t.vm.initUnsupportedMethodError(sourceLine, "#new", receiver)
},
},
}
}
// Instance methods -----------------------------------------------------
func builtinRangeInstanceMethods() []*BuiltinMethodObject {
return []*BuiltinMethodObject{
{
// Returns a Boolean of compared two ranges
//
// ```ruby
// (1..5) == (1..5) # => true
// (1..5) == (1..6) # => false
// ```
//
// @return [Boolean]
Name: "==",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
left := receiver.(*RangeObject)
r := args[0]
right, ok := r.(*RangeObject)
if !ok {
return FALSE
}
if left.Start == right.Start && left.End == right.End {
return TRUE
}
return FALSE
},
},
{
// Returns a Boolean of compared two ranges
//
// ```ruby
// (1..5) != (1..5) # => false
// (1..5) != (1..6) # => true
// ```
//
// @return [Boolean]
Name: "!=",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
left := receiver.(*RangeObject)
r := args[0]
right, ok := r.(*RangeObject)
if !ok {
return TRUE
}
if left.Start == right.Start && left.End == right.End {
return FALSE
}
return TRUE
},
},
{
// By using binary search, finds a value in range which meets the given condition in O(log n)
// where n is the size of the range.
//
// You can use this method in two use cases: a find-minimum mode and a find-any mode. In either
// case, the elements of the range must be monotone (or sorted) with respect to the block.
//
// In find-minimum mode (this is a good choice for typical use case), the block must return true
// or false, and there must be a value x so that:
//
// - the block returns false for any value which is less than x
// - the block returns true for any value which is greater than or equal to x.
//
// If x is within the range, this method returns the value x. Otherwise, it returns nil.
//
// ```ruby
// ary = [0, 4, 7, 10, 12]
// (0..4).bsearch {|i| ary[i] >= 4 } #=> 1
// (0..4).bsearch {|i| ary[i] >= 6 } #=> 2
// (0..4).bsearch {|i| ary[i] >= 8 } #=> 3
// (0..4).bsearch {|i| ary[i] >= 100 } #=> nil
// ```
//
// In find-any mode , the block must return a number, and there must be two values x and y
// (x <= y) so that:
//
// - the block returns a positive number for v if v < x
// - the block returns zero for v if x <= v < y
// - the block returns a negative number for v if y <= v
//
// This method returns any value which is within the intersection of the given range and x…y
// (if any). If there is no value that satisfies the condition, it returns nil.
//
// ```ruby
// ary = [0, 100, 100, 100, 200]
// (0..4).bsearch {|i| 100 - ary[i] } #=> 1, 2 or 3
// (0..4).bsearch {|i| 300 - ary[i] } #=> nil
// (0..4).bsearch {|i| 50 - ary[i] } #=> nil
// ```
//
// @return [Integer]
Name: "bsearch",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
if ran.Start < 0 || ran.End < 0 {
// if block is not used, it should be popped
t.callFrameStack.pop()
return NULL
}
var start, end int
if ran.Start < ran.End {
start, end = ran.Start, ran.End
} else {
start, end = ran.End, ran.Start
}
// the element of the range
// object with the highest value
ranEnd := end
var mid int
pivot := -1
for {
mid = (start + end) / 2
if (start+end)%2 != 0 {
mid++
}
result := t.builtinMethodYield(blockFrame, t.vm.InitIntegerObject(mid))
switch r := result.Target.(type) {
case *BooleanObject:
if r.value {
pivot = mid
}
if start >= end {
if pivot == -1 {
return NULL
}
return t.vm.InitIntegerObject(pivot)
}
if r.value {
end = mid - 1
} else if mid+1 > ranEnd {
return NULL
} else {
start = mid + 1
}
case *IntegerObject:
if r.value == 0 {
return t.vm.InitIntegerObject(mid)
}
if start == end {
return NULL
}
if r.value > 0 {
start = mid + 1
} else {
end = mid - 1
}
default:
return t.vm.InitErrorObject(errors.TypeError, sourceLine, "Expect Integer or Boolean type. got=%s", r.Class().Name)
}
}
},
},
{
// Iterates over the elements of range, passing each in turn to the block.
// Returns `nil`.
//
// ```ruby
// sum = 0
// (1..5).each do |i|
// sum = sum + i
// end
// sum # => 15
//
// sum = 0
// (-1..-5).each do |i|
// sum = sum + i
// end
// sum # => -15
// ```
//
// **Note:**
// - Only `do`-`end` block is supported for now: `{ }` block is unavailable.
// - Three-dot range `...` is not supported yet.
//
// @return [Range]
Name: "each",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
if blockFrame == nil {
return t.vm.InitErrorObject(errors.InternalError, sourceLine, errors.CantYieldWithoutBlockFormat)
}
ran.each(func(i int) error {
obj := t.vm.InitIntegerObject(i)
t.builtinMethodYield(blockFrame, obj)
return nil
})
return ran
},
},
{
// Returns the first value of the range.
//
// ```ruby
// (1..5).first # => 1
// (5..1).first # => 5
// (-2..3).first # => -2
// (-5..-7).first # => -5
// ```
//
// @return [Integer]
Name: "first",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
return t.vm.InitIntegerObject(ran.Start)
},
},
{
// The include method will check whether the integer object is in the range
//
// ```ruby
// (5..10).include?(10) # => true
// (5..10).include?(11) # => false
// (5..10).include?(7) # => true
// (5..10).include?(5) # => true
// (5..10).include?(4) # => false
// (-5..1).include?(-2) # => true
// (-5..-2).include?(-2) # => true
// (-5..-3).include?(-2) # => false
// (1..-5).include?(-2) # => true
// (-2..-5).include?(-2) # => true
// (-3..-5).include?(-2) # => false
// ```
// @return [Boolean]
Name: "include?",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
value := args[0].(*IntegerObject).value
ascendRangeBool := ran.Start <= ran.End && value >= ran.Start && value <= ran.End
descendRangeBool := ran.End <= ran.Start && value <= ran.Start && value >= ran.End
if ascendRangeBool || descendRangeBool {
return TRUE
}
return FALSE
},
},
{
// Returns the last value of the range.
//
// ```ruby
// (1..5).last # => 5
// (5..1).last # => 1
// (-2..3).last # => 3
// (-5..-7).last # => -7
// ```
//
// @return [Integer]
Name: "last",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
return t.vm.InitIntegerObject(ran.End)
},
},
{
// Loop through each element with the given range. Return a new array with each yield element. Only a block is required, and no other arguments are acceptable.
//
// ```ruby
// (1..10).map do |i|
// i * i
// end
//
// # => [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
// ```
// @return [Array]
Name: "map",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
r := receiver.(*RangeObject)
if blockFrame == nil {
return t.vm.InitErrorObject(errors.InternalError, sourceLine, errors.CantYieldWithoutBlockFormat)
}
if len(args) != 0 {
return t.vm.InitErrorObject(errors.ArgumentError, sourceLine, "Expect 0 argument. got=%d", len(args))
}
var elements []Object
r.each(func(i int) error {
if blockIsEmpty(blockFrame) {
elements = append(elements, NULL)
} else {
obj := t.vm.InitIntegerObject(i)
elements = append(elements, t.builtinMethodYield(blockFrame, obj).Target)
}
return nil
})
return t.vm.InitArrayObject(elements)
},
},
{
// Returns the size of the range
//
// ```ruby
// (1..5).size # => 5
// (3..9).size # => 7
// (-1..-5).size # => 5
// (-1..7).size # => 9
// ```
// @return [Integer]
Name: "size",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
if ran.Start <= ran.End {
return t.vm.InitIntegerObject(ran.End - ran.Start + 1)
}
return t.vm.InitIntegerObject(ran.Start - ran.End + 1)
},
},
{
// The step method can loop through the first to the last of the object with given steps.
// An error will occur if not yielded to the block.
//
// ```ruby
// sum = 0
// (2..9).step(3) do |i|
// sum = sum + i
// end
// sum # => 15
//
// sum = 0
// (2..-9).step(3) do |i|
// sum = sum + i
// end
// sum # => 0
//
// sum = 0
// (-1..5).step(2) do |i|
// sum = sum + 1
// end
// sum # => 8
//
// sum = 0
// (-1..-5).step(2) do |i|
// sum = sum + 1
// end
// sum # => 0
// ```
//
// @return [Range]
Name: "step",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
if blockFrame == nil {
return t.vm.InitErrorObject(errors.InternalError, sourceLine, errors.CantYieldWithoutBlockFormat)
}
stepValue := args[0].(*IntegerObject).value
if stepValue == 0 {
return t.vm.InitErrorObject(errors.ArgumentError, sourceLine, "Step can't be 0")
} else if stepValue < 0 {
return t.vm.InitErrorObject(errors.ArgumentError, sourceLine, "Step can't be negative")
}
blockFrameUsed := false
ran.each(func(i int) error {
if (i-ran.Start)%stepValue != 0 {
return nil
}
obj := t.vm.InitIntegerObject(i)
t.builtinMethodYield(blockFrame, obj)
blockFrameUsed = true
return nil
})
// if block is not used, it should be popped
if !blockFrameUsed {
t.callFrameStack.pop()
}
return ran
},
},
{
// Returns an Array object that contains the values of the range.
//
// ```ruby
// (1..5).to_a # => [1, 2, 3, 4, 5]
// (1..5).to_a[2] # => 3
// (-1..-5).to_a # => [-1, -2, -3, -4, -5]
// (-1..3).to_a # => [-1, 0, 1, 2, 3]
// ```
//
// @return [Array]
Name: "to_a",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ro := receiver.(*RangeObject)
elems := []Object{}
var iterAdd int
if ro.Start <= ro.End {
iterAdd = 1
} else {
iterAdd = -1
}
for i := ro.Start; i != (ro.End + iterAdd); i += iterAdd {
elems = append(elems, t.vm.InitIntegerObject(i))
}
return t.vm.InitArrayObject(elems)
},
},
{
// The to_s method can convert range to string format
//
// ```ruby
// (1..5).to_s # "(1..5)"
// (-1..-3).to_s # "(-1..-3)"
// ```
// @return [String]
Name: "to_s",
Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
ran := receiver.(*RangeObject)
return t.vm.InitStringObject(ran.toString())
},
},
}
}
// Internal functions ===================================================
// Functions for initialization -----------------------------------------
func (vm *VM) initRangeObject(start, end int) *RangeObject {
return &RangeObject{
baseObj: &baseObj{class: vm.topLevelClass(classes.RangeClass)},
Start: start,
End: end,
}
}
func (vm *VM) initRangeClass() *RClass {
rc := vm.initializeClass(classes.RangeClass)
rc.setBuiltinMethods(builtinRangeInstanceMethods(), false)
rc.setBuiltinMethods(builtinRangeClassMethods(), true)
vm.libFiles = append(vm.libFiles, "range.gb")
vm.libFiles = append(vm.libFiles, "range_enumerator.gb")
return rc
}
// Polymorphic helper functions -----------------------------------------
// toString returns the object's name as the string format
func (ro *RangeObject) toString() string {
return fmt.Sprintf("(%d..%d)", ro.Start, ro.End)
}
// toJSON just delegates to toString
func (ro *RangeObject) toJSON(t *Thread) string {
return ro.toString()
}
// Value returns range object's string format
func (ro *RangeObject) Value() interface{} {
return ro.toString()
}
func (ro *RangeObject) each(f func(int) error) (err error) {
var inc int
if ro.End-ro.Start >= 0 {
inc = 1
} else {
inc = -1
}
for i := ro.Start; i != ro.End+inc; i += inc {
if err = f(i); err != nil {
return err
}
}
return
}