fdd5aec172
This refactors and improves the `#eval` command, introducing some new
features.
* Now evaluated results can be represented using `ToExpr` and pretty
printing. This means **hoverable output**. If `ToExpr` fails, it then
tries `Repr` and then `ToString`. The `eval.pp` option controls whether
or not to try `ToExpr`.
* There is now **auto-derivation** of `Repr` instances, enabled with the
`pp.derive.repr` option (default to **true**). For example:
```lean
inductive Baz
| a | b
#eval Baz.a
-- Baz.a
```
It simply does `deriving instance Repr for Baz` when there's no way to
represent `Baz`. If core Lean gets `ToExpr` derive handlers, they could
be used here as well.
* The option `eval.type` controls whether or not to include the type in
the output. For now the default is false.
* Now things like `#eval do return 2` work. It tries using
`CommandElabM`, `TermElabM`, or `IO` when the monad is unknown.
* Now there is no longer `Lean.Eval` or `Lean.MetaEval`. These each used
to be responsible for both adapting monads and printing results. The
concerns have been split into two. (1) The `MonadEval` class is
responsible for adapting monads for evaluation (it is similar to
`MonadLift`, but instances are allowed to use default data when
initializing state) and (2) finding a way to represent results is
handled separately.
* Error messages about failed instance synthesis are now more precise.
Once it detects that a `MonadEval` class applies, then the error message
will be specific about missing `ToExpr`/`Repr`/`ToString` instances.
* Fixes a bug where `Repr`/`ToString` instances can't be found by
unfolding types "under the monad". For example, this works now:
```lean
def Foo := List Nat
def Foo.mk (l : List Nat) : Foo := l
#eval show Lean.CoreM Foo from do return Foo.mk [1,2,3]
```
* Elaboration errors now abort evaluation. This eliminates some
not-so-relevant error messages.
* Now evaluating a value of type `m Unit` never prints a blank message.
* Fixes bugs where evaluating `MetaM` and `CoreM` wouldn't collect log
messages.
The `run_cmd`, `run_elab`, and `run_meta` commands are now frontends for
`#eval`.
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1.4 KiB
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27 lines
1.4 KiB
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10.000000
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10.000000
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0.100000
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0.000000
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5843.000000
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8430000.000000
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0.000001
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123.000000
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123000.000000
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-8.534000
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scientific.lean:14:6-14:7: error: invalid occurrence of `·` notation, it must be surrounded by parentheses (e.g. `(· + 1)`)
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scientific.lean:14:7-14:10: error: unexpected token; expected command
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scientific.lean:15:6-15:7: error: invalid occurrence of `·` notation, it must be surrounded by parentheses (e.g. `(· + 1)`)
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scientific.lean:15:7-15:12: error: unexpected token; expected command
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scientific.lean:16:6-16:7: error: invalid occurrence of `·` notation, it must be surrounded by parentheses (e.g. `(· + 1)`)
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scientific.lean:16:7-16:16: error: unexpected token; expected command
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scientific.lean:19:6-19:7: error: unknown identifier 'e'
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scientific.lean:20:9: error: missing exponent digits in scientific literal
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scientific.lean:21:9: error: missing exponent digits in scientific literal
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scientific.lean:22:9: error: missing exponent digits in scientific literal
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scientific.lean:23:9: error: missing exponent digits in scientific literal
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scientific.lean:24:9: error: missing exponent digits in scientific literal
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scientific.lean:25:9: error: missing exponent digits in scientific literal
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scientific.lean:26:6-26:8: error: invalid dotted identifier notation, unknown identifier `Nat.E` from expected type
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Nat
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scientific.lean:27:7-27:9: error: unknown identifier 'E3'
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scientific.lean:28:7: error: missing exponent digits in scientific literal
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