54 lines
1.7 KiB
Text
54 lines
1.7 KiB
Text
/-
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Copyright (c) 2018 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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Authors: Leonardo de Moura
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-/
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prelude
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import init.lean.parser.parsec
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namespace lean
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namespace parser
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open monad_parsec
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variables {m : Type → Type} {μ : Type} [monad m] [monad_parsec μ m] [alternative m]
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def parse_hex_digit : m nat :=
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( (do d ← digit, pure $ d.to_nat - '0'.to_nat)
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<|> (do c ← satisfy (λ c, 'a'.val ≤ c.val && c.val ≤ 'f'.val), pure $ 10 + (c.to_nat - 'a'.to_nat))
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<|> (do c ← satisfy (λ c, 'A'.val ≤ c.val && c.val ≤ 'F'.val), pure $ 10 + (c.to_nat - 'A'.to_nat)))
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<?> "hexadecimal"
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def parse_quoted_char : m char :=
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do it ← left_over,
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c ← any,
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if c = '\\' then pure '\\'
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else if c = '\"' then pure '\"'
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else if c = '\'' then pure '\''
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else if c = 'n' then pure '\n'
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else if c = 't' then pure '\t'
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else if c = 'x' then do {
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d₁ ← parse_hex_digit,
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d₂ ← parse_hex_digit,
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pure $ char.of_nat (16*d₁ + d₂) }
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else if c = 'u' then do {
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d₁ ← parse_hex_digit,
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d₂ ← parse_hex_digit,
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d₃ ← parse_hex_digit,
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d₄ ← parse_hex_digit,
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pure $ char.of_nat (16*(16*(16*d₁ + d₂) + d₃) + d₄) }
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else unexpected_at "quoted character" it
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def parse_string_literal_aux : nat → string → m string
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| 0 s := ch '\"' *> pure s
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| (n+1) s := do
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c ← any,
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if c = '\\' then do c ← parse_quoted_char, parse_string_literal_aux n (s.push c)
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else if c = '\"' then pure s
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else parse_string_literal_aux n (s.push c)
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def parse_string_literal : m string :=
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do ch '\"',
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r ← remaining,
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parse_string_literal_aux r ""
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end parser
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end lean
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