7557542bc2
This PR modifies the `structure` syntax so that parents can be named, like in ```lean structure S extends toParent : P ``` **Breaking change:** The syntax is also modified so that the resultant type comes *before* the `extends` clause, for example `structure S : Prop extends P`. This is necessary to prevent a parsing ambiguity, but also this is the natural place for the resultant type. Implements RFC #7099. Will need followup PRs for cleanup after a stage0 update.
24 lines
541 B
Text
24 lines
541 B
Text
class One (α : Type) where
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one : α
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variable (R A : Type) [One R] [One A]
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class OneHom where
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toFun : R → A
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map_one : toFun One.one = One.one
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structure Subone where
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mem : R → Prop
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one_mem : mem One.one
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structure Subalgebra [OneHom R A] : Type extends Subone A where
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algebraMap_mem : ∀ r : R, mem (OneHom.toFun r)
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one_mem := OneHom.map_one (R := R) (A := A) ▸ algebraMap_mem One.one
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/--
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error: fields missing: 'one_mem'
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-/
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#guard_msgs in
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example [OneHom R A] : Subalgebra R A where
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mem := _
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algebraMap_mem := _
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