108 lines
2.0 KiB
Go
108 lines
2.0 KiB
Go
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package multiless
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type (
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// A helper for long chains of "less-than" comparisons, where later comparisons are only
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// required if earlier ones haven't resolved the comparison.
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Computation struct {
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ok bool
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less bool
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}
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)
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func New() Computation {
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return Computation{}
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}
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func (me Computation) EagerSameLess(same, less bool) Computation {
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if me.ok || same {
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return me
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}
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return Computation{
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ok: true,
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less: less,
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}
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}
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func (me Computation) LazySameLess(lazy func() (same, less bool)) Computation {
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if me.ok {
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return me
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}
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same, less := lazy()
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if !same {
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me.less = less
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}
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return me
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}
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// Sorts so that false comes before true.
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func (me Computation) Bool(l, r bool) Computation {
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return me.EagerSameLess(l == r, r)
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}
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func (me Computation) Uint32(l, r uint32) Computation {
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return me.EagerSameLess(l == r, l < r)
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}
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func (me Computation) Int64(l, r int64) Computation {
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return me.EagerSameLess(l == r, l < r)
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}
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func (me Computation) Uint64(l, r uint64) Computation {
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return me.EagerSameLess(l == r, l < r)
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}
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func (me Computation) Int(l, r int) Computation {
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return me.EagerSameLess(l == r, l < r)
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}
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func (me Computation) CmpInt64(i int64) Computation {
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return me.EagerSameLess(i == 0, i < 0)
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}
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func (me Computation) Cmp(i int) Computation {
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return me.EagerSameLess(i == 0, i < 0)
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}
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func (me Computation) Uintptr(l, r uintptr) Computation {
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return me.EagerSameLess(l == r, l < r)
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}
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func (me Computation) Less() bool {
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return me.less
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}
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func (me Computation) Ok() bool {
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return me.ok
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}
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func (me Computation) LessOk() (less, ok bool) {
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return me.less, me.ok
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}
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func (me Computation) MustLess() bool {
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less, ok := me.LessOk()
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if !ok {
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panic("computation has not differentiated yet")
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}
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return less
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}
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func (me Computation) Float64(l, r float64) Computation {
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return me.EagerSameLess(l == r, l < r)
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}
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func (me Computation) Lazy(f func() Computation) Computation {
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if me.ok {
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return me
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}
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return f()
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}
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func (me Computation) AndThen(then Computation) Computation {
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if me.ok {
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return me
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} else {
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return then
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}
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}
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