719765ec5c
This PR refines and clarifies the `meta` phase distinction in the module system. * `meta import A` without `public` now has the clarified meaning of "enable compile-time evaluation of declarations in or above `A` in the current module, but not downstream". This is now checked statically by enforcing that public meta defs, which therefore may be referenced from outside, can only use public meta imports, and that global evaluating attributes such as `@[term_parser]` can only be applied to public meta defs. * `meta def`s may no longer reference non-meta defs even when in the same module. This clarifies the meta distinction as well as improves locality of (new) error messages. * parser references in `syntax` are now also properly tracked as meta references. * A `meta import` of an `import` now properly loads only the `.ir` of the nested module for the purposes of execution instead of also making its declarations available for general elaboration. * `initialize` is now no longer being run on import under the module system, which is now covered by `meta initialize`.
36 lines
974 B
Text
36 lines
974 B
Text
module
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public import Lean
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public meta import Lean.Elab.Tactic
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open Lean Meta Elab Tactic Try
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-- Install a `TryTactic` handler for `assumption`
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@[local try_tactic assumption]
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meta def evalTryApply : TryTactic := fun tac => do
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-- We just use the default implementation, but return a different tactic.
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evalAssumption tac
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`(tactic| (trace "worked"; assumption))
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/--
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info: Try this:
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· trace "worked"; assumption
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-/
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#guard_msgs (info) in
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example (h : False) : False := by
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try? (max := 1) -- at most one solution
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-- `try?` uses `evalAndSuggest` the attribute `[try_tactic]` is used to extend `evalAndSuggest`.
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-- Let's define our own `try?` that uses `evalAndSuggest`
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elab stx:"my_try?" : tactic => do
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-- Things to try
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let toTry ← `(tactic| attempt_all | assumption | apply True | rfl)
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evalAndSuggest stx toTry
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/--
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info: Try these:
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• · trace "worked"; assumption
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• rfl
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-/
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#guard_msgs (info) in
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example (a : Nat) (h : a = a) : a = a := by
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my_try?
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