133 lines
4.8 KiB
Text
133 lines
4.8 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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Author: Sebastian Ullrich
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Module-level parsers
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-/
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prelude
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import init.lean.parser.command
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namespace lean
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namespace parser
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open combinators monadParsec
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open parser.hasTokens parser.hasView
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local postfix `?`:10000 := optional
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local postfix *:10000 := combinators.many
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local postfix +:10000 := combinators.many1
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structure moduleParserConfig extends commandParserConfig :=
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(commandParsers : tokenMap commandParser)
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instance moduleParserConfigCoe : hasCoe moduleParserConfig commandParserConfig :=
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⟨moduleParserConfig.toCommandParserConfig⟩
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section
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@[derive monad alternative monadReader monadState monadParsec monadExcept]
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def moduleParserM := stateT parserState $ parserT moduleParserConfig id
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abbrev moduleParser := moduleParserM syntax
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end
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instance moduleParserM.liftParserT (ρ : Type) [hasLiftT moduleParserConfig ρ] :
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hasMonadLift (parserT ρ id) moduleParserM :=
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{ monadLift := λ α x st cfg, (λ a, (a, st)) <$> x.run ↑cfg }
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section
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local attribute [reducible] basicParserM
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instance moduleParserM.basicParserM (ρ : Type) [hasLiftT moduleParserConfig ρ] :
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hasMonadLift basicParserM moduleParserM :=
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inferInstance
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end
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namespace module
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@[derive parser.hasView parser.hasTokens]
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def prelude.parser : basicParser :=
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node! «prelude» ["prelude"]
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@[derive parser.hasView parser.hasTokens]
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def importPath.parser : basicParser :=
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-- use `raw` to ignore registered tokens like ".."
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node! importPath [
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dirups: (rawStr ".")*,
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module: ident.parser]
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@[derive parser.hasView parser.hasTokens]
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def import.parser : basicParser :=
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node! «import» ["import", imports: importPath.parser+]
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@[derive parser.hasView parser.hasTokens]
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def header.parser : basicParser :=
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node! «header» [«prelude»: prelude.parser?, imports: import.parser*]
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@[pattern] def eoi : syntaxNodeKind := ⟨`lean.parser.module.eoi⟩
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def eoi.parser : moduleParser := do
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monadParsec.eoi,
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it ← leftOver,
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-- add `eoi` node for left-over input
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let stop := it.toEnd,
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pure $ syntax.mkNode eoi [syntax.atom ⟨some ⟨⟨stop, stop⟩, stop.offset, ⟨stop, stop⟩⟩, ""⟩]
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/-- Read command, recovering from errors inside commands (attach partial syntax tree)
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as well as unknown commands (skip input). -/
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private def commandWrecAux : bool → nat → moduleParserM (bool × syntax)
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| recovering 0 := error "unreachable"
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| recovering (nat.succ n) := do
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-- terminate at EOF
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nat.succ _ ← remaining | (prod.mk ff) <$> eoi.parser,
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(recovering, c) ← catch (do {
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cfg ← read,
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c ← monadLift $ command.parser.run cfg.commandParsers,
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pure (ff, some c)
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} <|> do {
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-- unknown command: try to skip token, or else single character
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when (¬ recovering) $ do {
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it ← leftOver,
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logMessage {expected := dlist.singleton "command", it := it, custom := some ()}
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},
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try (monadLift token *> pure ()) <|> (any *> pure ()),
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pure (tt, none)
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}) $ λ msg, do {
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-- error inside command: log error, return partial syntax tree
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logMessage msg,
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pure (tt, some msg.custom.get)
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},
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/- NOTE: We need to make very sure that these recursive calls are happening in tail positions.
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Otherwise, resuming the coroutine is linear in the number of previous commands. -/
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match c with
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| some c := pure (recovering, c)
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| none := commandWrecAux recovering n
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def parseCommandWithRecovery (recovering : bool) :=
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do { rem ← remaining, commandWrecAux recovering rem.succ }
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end module
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open module
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structure moduleParserSnapshot :=
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-- it there was a parse error in the previous command, we shouldn't complain if parsing immediately after it
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-- fails as well
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(recovering : bool)
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(it : string.iterator)
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-- return (partial) syntax tree and single fatal or multiple non-fatal messages
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def resumeModuleParser {α : Type} (cfg : moduleParserConfig) (snap : moduleParserSnapshot) (mkRes : α → syntax × moduleParserSnapshot)
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(p : moduleParserM α) : syntax × except message (moduleParserSnapshot × messageLog) :=
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let (r, _) := ((((prod.mk <$> p <*> leftOver).run {messages:=messageLog.empty}).run cfg).runFrom snap.it).run {} in
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match r with
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| except.ok ((a, it), st) := let (stx, snap) := mkRes a in (stx, except.ok ({snap with it := it}, st.messages))
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| except.error msg := (msg.custom.get, except.error $ messageOfParsecMessage cfg msg)
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def parseHeader (cfg : moduleParserConfig) :=
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let snap := {moduleParserSnapshot . recovering := ff, it := cfg.input.mkIterator} in
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resumeModuleParser cfg snap (λ stx, (stx, snap)) $ do
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-- `token` assumes that there is no leading whitespace
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monadLift whitespace,
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monadLift header.parser
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def parseCommand (cfg) (snap) := resumeModuleParser cfg snap (λ p, (prod.snd p, {snap with recovering := prod.fst p}))
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(parseCommandWithRecovery snap.recovering)
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end parser
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end lean
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