a0a8103804
This suggestion has been discussed at Slack. We have decided to use #"c" as notation because we wanted to allow `'` in the beginning of identifiers like in SML and F*. In particular, we wanted to allow users to use 'a 'b 'c for naming type parameters like in SML. However, nobody used this notation. In the Lean standard library, we are using greek letters for naming type parameters. So, there is no real motivation for the ugly #"c" syntax.
57 lines
1.6 KiB
Text
57 lines
1.6 KiB
Text
/-
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Copyright (c) 2017 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Gabriel Ebner
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-/
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prelude
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import .basic .lemmas init.meta init.data.int
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namespace char
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def is_whitespace (c : char) : Prop :=
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c ∈ [' ', '\t', '\n']
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def is_upper (c : char) : Prop :=
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c.val ≥ 65 ∧ c.val ≤ 90
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def is_lower (c : char) : Prop :=
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c.val ≥ 97 ∧ c.val ≤ 122
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def is_alpha (c : char) : Prop :=
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c.is_upper ∨ c.is_lower
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def is_digit (c : char) : Prop :=
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c.val ≥ 48 ∧ c.val ≤ 57
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def is_alphanum (c : char) : Prop :=
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c.is_alpha ∨ c.is_digit
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def is_punctuation (c : char) : Prop :=
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c ∈ [' ', ',', '.', '?', '!', ';', '-', '\'']
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def to_lower (c : char) : char :=
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let n := to_nat c in
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if n >= 65 ∧ n <= 90 then of_nat (n + 32) else c
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instance decidable_is_whitespace : decidable_pred is_whitespace :=
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begin intro c, delta is_whitespace, apply_instance end
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instance decidable_is_upper : decidable_pred is_upper :=
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begin intro c, delta is_upper, apply_instance end
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instance decidable_is_lower : decidable_pred is_lower :=
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begin intro c, delta is_lower, apply_instance end
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instance decidable_is_alpha : decidable_pred is_alpha :=
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begin intro c, delta is_alpha, apply_instance end
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instance decidable_is_digit : decidable_pred is_digit :=
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begin intro c, delta is_digit, apply_instance end
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instance decidable_is_alphanum : decidable_pred is_alphanum :=
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begin intro c, delta is_alphanum, apply_instance end
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instance decidable_is_punctuation : decidable_pred is_punctuation :=
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begin intro c, delta is_punctuation, apply_instance end
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end char
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