55626ba60d
We are going to start making drastic changes in the parser, elaborator, attributes, etc. Examples: - No View objects. I am going to implement match_syntax. - No RecT in the parser. I am going to implement parser extensions using an approach similar to the one I used to implement environment extensions. - No Parsec. I will use an approach similar to the one used in the experiment https://github.com/leanprover/lean4/tree/master/tests/playground/parser It is easier to perform these changes with the new frontend disabled. I will slowly re-active it as I apply the changes. cc @kha
54 lines
1.6 KiB
Text
54 lines
1.6 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 MonadParsec
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variables {m : Type → Type} {μ : Type} [Monad m] [MonadParsec μ m] [Alternative m]
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def parseHexDigit : m Nat :=
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( (do d ← digit, pure $ d.toNat - '0'.toNat)
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<|> (do c ← satisfy (λ c, 'a'.val ≤ c.val && c.val ≤ 'f'.val), pure $ 10 + (c.toNat - 'a'.toNat))
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<|> (do c ← satisfy (λ c, 'A'.val ≤ c.val && c.val ≤ 'F'.val), pure $ 10 + (c.toNat - 'A'.toNat)))
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<?> "hexadecimal"
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def parseQuotedChar : m Char :=
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do it ← leftOver,
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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 ← parseHexDigit,
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d₂ ← parseHexDigit,
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pure $ Char.ofNat (16*d₁ + d₂) }
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else if c = 'u' then do {
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d₁ ← parseHexDigit,
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d₂ ← parseHexDigit,
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d₃ ← parseHexDigit,
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d₄ ← parseHexDigit,
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pure $ Char.ofNat (16*(16*(16*d₁ + d₂) + d₃) + d₄) }
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else unexpectedAt "quoted character" it
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def parseStringLiteralAux : 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 ← parseQuotedChar, parseStringLiteralAux n (s.push c)
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else if c = '\"' then pure s
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else parseStringLiteralAux n (s.push c)
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def parseStringLiteral : m String :=
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do ch '\"',
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r ← remaining,
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parseStringLiteralAux r ""
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end Parser
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end Lean
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