57 lines
1.3 KiB
Go
57 lines
1.3 KiB
Go
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package versions
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import "fmt"
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type setSubtract struct {
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from setI
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sub setI
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}
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func (s setSubtract) Has(v Version) bool {
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return s.from.Has(v) && !s.sub.Has(v)
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}
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func (s setSubtract) AllRequested() Set {
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// Our set requests anything that is requested by "from", unless it'd
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// be excluded by "sub". Notice that the whole of "sub" is used, rather
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// than just the requested parts, because requesting is a positive
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// action only.
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return Set{setI: s.from}.AllRequested().Subtract(Set{setI: s.sub})
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}
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func (s setSubtract) GoString() string {
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return fmt.Sprintf("(%#v).Subtract(%#v)", s.from, s.sub)
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}
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// Subtract returns a new set that has all of the versions from the receiver
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// except for any versions in the other given set.
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//
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// If the receiver is finite then the returned set is also finite.
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func (s Set) Subtract(other Set) Set {
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if other == None || s == None {
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return s
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}
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if other == All {
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return None
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}
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return Set{
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setI: setSubtract{
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from: s.setI,
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sub: other.setI,
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},
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}
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}
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var _ setFinite = setSubtract{}
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func (s setSubtract) isFinite() bool {
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// subtract is finite if its "from" is finite
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return isFinite(s.from)
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}
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func (s setSubtract) listVersions() List {
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ret := s.from.(setFinite).listVersions()
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ret = ret.Filter(Set{setI: s.sub})
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return ret
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}
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