lean4-htt/library/init/Lean/Parser/level.lean
2019-03-21 15:06:44 -07:00

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/-
Copyright (c) 2018 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Sebastian Ullrich
Level-Level parsers
-/
prelude
import init.lean.parser.pratt
namespace Lean
namespace Parser
open Combinators Parser.HasView MonadParsec
@[derive Monad Alternative MonadReader MonadParsec MonadExcept MonadRec monadBasicParser]
def LevelParserM := RecT Nat Syntax BasicParserM
abbrev levelParser := LevelParserM Syntax
/-- A Level Parser for a suffix or infix notation that accepts a preceding Term Level. -/
@[derive Monad Alternative MonadReader MonadParsec MonadExcept MonadRec monadBasicParser]
def TrailingLevelParserM := ReaderT Syntax LevelParserM
abbrev trailingLevelParser := TrailingLevelParserM Syntax
instance trailingLevelParserCoe : HasCoe levelParser trailingLevelParser :=
⟨λ x _, x⟩
@[derive Parser.HasTokens Parser.HasView]
def Level.Parser (rbp := 0) : levelParser :=
recurse rbp <?> "universe Level"
namespace Level
/-- Access leading Term -/
def getLeading : trailingLevelParser := read
instance : HasTokens getLeading := default _
instance : HasView Syntax getLeading := default _
@[derive Parser.HasTokens Parser.HasView]
def paren.Parser : levelParser :=
node! «paren» ["(":maxPrec, inner: Level.Parser 0, ")"]
@[derive Parser.HasTokens Parser.HasView]
def leading.Parser : levelParser :=
nodeChoice! leading {
max: symbolOrIdent "max",
imax: symbolOrIdent "imax",
hole: symbol "_" maxPrec,
paren: paren.Parser,
lit: number.Parser,
var: ident.Parser
}
@[derive Parser.HasTokens Parser.HasView]
def app.Parser : trailingLevelParser :=
node! app [fn: getLeading, Arg: Level.Parser maxPrec]
@[derive Parser.HasTokens Parser.HasView]
def addLit.Parser : trailingLevelParser :=
node! addLit [lhs: getLeading, "+", rhs: number.Parser]
@[derive Parser.HasTokens Parser.HasView]
def trailing.Parser : trailingLevelParser :=
nodeChoice! trailing {
app: app.Parser,
addLit: addLit.Parser
}
end Level
@[derive Parser.HasTokens Parser.HasView]
def levelParser.run (p : levelParser) : basicParser :=
prattParser Level.leading.Parser Level.trailing.Parser p
instance levelParserCoe : HasCoe levelParser basicParser :=
⟨levelParser.run⟩
end Parser
end Lean