18 lines
458 B
Text
18 lines
458 B
Text
/- ANCHOR: doc -/
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open Lean in
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macro "begin " ts:tactic,*,? i:"end" : term => do
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-- preserve position of the last token, which is used
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-- as the error position in case of an unfinished proof
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`(by { $[$ts:tactic]* }%$i)
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theorem ex1 (x : Nat) : x + 0 = 0 + x :=
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begin
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rw [Nat.zero_add],
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rw [Nat.add_zero],
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end
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/- ANCHOR_END: doc -/
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theorem ex2 (x : Nat) : x + 0 = 0 + x :=
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begin
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rw [Nat.zero_add]
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end -- error should be shown here
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