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PR: builtin range function #326 (#328)
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* builtin range function #326

* change empty range logic

* fix unit test error message

* fix github env (#329)

* fix ErrInvalidRangeStep comments

* fix github env (#329)

* builtin range function #326

* change empty range logic

* fix unit test error message

* fix ErrInvalidRangeStep comments

* fix lint

Co-authored-by: geseq <[email protected]>
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@endink @geseq
endink and geseq authored Mar 2, 2021
1 parent c51d02f commit 8858304
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69 changes: 69 additions & 0 deletions builtins.go
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Original file line number Diff line number Diff line change
Expand Up @@ -121,6 +121,10 @@ var builtinFuncs = []*BuiltinFunction{
Name: "format",
Value: builtinFormat,
},
{
Name: "range",
Value: builtinRange,
},
}

// GetAllBuiltinFunctions returns all builtin function objects.
Expand Down Expand Up @@ -323,6 +327,71 @@ func builtinLen(args ...Object) (Object, error) {
}
}

//range(start, stop[, step])
func builtinRange(args ...Object) (Object, error) {
numArgs := len(args)
if numArgs < 2 || numArgs > 3 {
return nil, ErrWrongNumArguments
}
var start, stop, step *Int

for i, arg := range args {
v, ok := args[i].(*Int)
if !ok {
var name string
switch i {
case 0:
name = "start"
case 1:
name = "stop"
case 2:
name = "step"
}

return nil, ErrInvalidArgumentType{
Name: name,
Expected: "int",
Found: arg.TypeName(),
}
}
if i == 2 && v.Value <= 0 {
return nil, ErrInvalidRangeStep
}
switch i {
case 0:
start = v
case 1:
stop = v
case 2:
step = v
}
}

if step == nil {
step = &Int{Value: int64(1)}
}

return buildRange(start.Value, stop.Value, step.Value), nil
}

func buildRange(start, stop, step int64) *Array {
array := &Array{}
if start <= stop {
for i := start; i < stop; i += step {
array.Value = append(array.Value, &Int{
Value: i,
})
}
} else {
for i := start; i > stop; i -= step {
array.Value = append(array.Value, &Int{
Value: i,
})
}
}
return array
}

func builtinFormat(args ...Object) (Object, error) {
numArgs := len(args)
if numArgs == 0 {
Expand Down
153 changes: 153 additions & 0 deletions builtins_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -351,3 +351,156 @@ func Test_builtinSplice(t *testing.T) {
})
}
}

func Test_builtinRange(t *testing.T) {
var builtinRange func(args ...tengo.Object) (tengo.Object, error)
for _, f := range tengo.GetAllBuiltinFunctions() {
if f.Name == "range" {
builtinRange = f.Value
break
}
}
if builtinRange == nil {
t.Fatal("builtin range not found")
}
tests := []struct {
name string
args []tengo.Object
result *tengo.Array
wantErr bool
wantedErr error
}{
{name: "no args", args: []tengo.Object{}, wantErr: true,
wantedErr: tengo.ErrWrongNumArguments,
},
{name: "single args", args: []tengo.Object{&tengo.Map{}},
wantErr: true,
wantedErr: tengo.ErrWrongNumArguments,
},
{name: "4 args", args: []tengo.Object{&tengo.Map{}, &tengo.String{}, &tengo.String{}, &tengo.String{}},
wantErr: true,
wantedErr: tengo.ErrWrongNumArguments,
},
{name: "invalid start",
args: []tengo.Object{&tengo.String{}, &tengo.String{}},
wantErr: true,
wantedErr: tengo.ErrInvalidArgumentType{
Name: "start", Expected: "int", Found: "string"},
},
{name: "invalid stop",
args: []tengo.Object{&tengo.Int{}, &tengo.String{}},
wantErr: true,
wantedErr: tengo.ErrInvalidArgumentType{
Name: "stop", Expected: "int", Found: "string"},
},
{name: "invalid step",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{}, &tengo.String{}},
wantErr: true,
wantedErr: tengo.ErrInvalidArgumentType{
Name: "step", Expected: "int", Found: "string"},
},
{name: "zero step",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{}, &tengo.Int{}}, //must greate than 0
wantErr: true,
wantedErr: tengo.ErrInvalidRangeStep,
},
{name: "negative step",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{}, intObject(-2)}, //must greate than 0
wantErr: true,
wantedErr: tengo.ErrInvalidRangeStep,
},
{name: "same bound",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{}},
wantErr: false,
result: &tengo.Array{
Value: nil,
},
},
{name: "positive range",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{Value: 5}},
wantErr: false,
result: &tengo.Array{
Value: []tengo.Object{
intObject(0),
intObject(1),
intObject(2),
intObject(3),
intObject(4),
},
},
},
{name: "negative range",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{Value: -5}},
wantErr: false,
result: &tengo.Array{
Value: []tengo.Object{
intObject(0),
intObject(-1),
intObject(-2),
intObject(-3),
intObject(-4),
},
},
},

{name: "positive with step",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{Value: 5}, &tengo.Int{Value: 2}},
wantErr: false,
result: &tengo.Array{
Value: []tengo.Object{
intObject(0),
intObject(2),
intObject(4),
},
},
},

{name: "negative with step",
args: []tengo.Object{&tengo.Int{}, &tengo.Int{Value: -10}, &tengo.Int{Value: 2}},
wantErr: false,
result: &tengo.Array{
Value: []tengo.Object{
intObject(0),
intObject(-2),
intObject(-4),
intObject(-6),
intObject(-8),
},
},
},

{name: "large range",
args: []tengo.Object{intObject(-10), intObject(10), &tengo.Int{Value: 3}},
wantErr: false,
result: &tengo.Array{
Value: []tengo.Object{
intObject(-10),
intObject(-7),
intObject(-4),
intObject(-1),
intObject(2),
intObject(5),
intObject(8),
},
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got, err := builtinRange(tt.args...)
if (err != nil) != tt.wantErr {
t.Errorf("builtinRange() error = %v, wantErr %v",
err, tt.wantErr)
return
}
if tt.wantErr && tt.wantedErr.Error() != err.Error() {
t.Errorf("builtinRange() error = %v, wantedErr %v",
err, tt.wantedErr)
}
if tt.result != nil && !reflect.DeepEqual(tt.result, got) {
t.Errorf("builtinRange() arrays are not equal expected"+
" %s, got %s", tt.result, got.(*tengo.Array))
}
})
}
}
3 changes: 3 additions & 0 deletions errors.go
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,9 @@ var (
// ErrNotImplemented is an error where an Object has not implemented a
// required method.
ErrNotImplemented = errors.New("not implemented")

// ErrInvalidRangeStep is an error where the step parameter is less than or equal to 0 when using builtin range function.
ErrInvalidRangeStep = errors.New("range step must be greater than 0")
)

// ErrInvalidArgumentType represents an invalid argument value type error.
Expand Down

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