138 lines
5.4 KiB
Text
138 lines
5.4 KiB
Text
import init.lean.message init.lean.parser.syntax init.lean.parser.trie init.lean.parser.basic
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namespace lean
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namespace flat_parser
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open string
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open parser (syntax)
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open parser (trie token_map)
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structure token_config :=
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(«prefix» : string)
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(lbp : nat := 0)
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structure frontend_config :=
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(filename : string)
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(input : string)
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(file_map : file_map)
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/- Remark: if we have a node in the trie with `some token_config`, the string induced by the path is equal to the `token_config.prefix`. -/
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structure parser_config extends frontend_config :=
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(tokens : trie token_config)
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-- Backtrackable state
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structure parser_state :=
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(messages : message_log)
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structure token_cache_entry :=
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(start_it stop_it : string.iterator)
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(tk : syntax)
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-- Non-backtrackable state
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structure parser_cache :=
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(token_cache : option token_cache_entry := none)
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inductive result (α : Type)
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| ok (a : α) (it : iterator) (cache : parser_cache) (state : parser_state) (eps : bool) : result
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| error {} (it : iterator) (cache : parser_cache) (msg : string) (stx : syntax) (eps : bool) : result
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inductive result.is_ok {α : Type} : result α → Prop
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| mk (a : α) (it : iterator) (cache : parser_cache) (state : parser_state) (eps : bool) : result.is_ok (result.ok a it cache state eps)
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theorem error_is_not_ok {α : Type} {it : iterator} {cache : parser_cache} {msg : string} {stx : syntax} {eps : bool}
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(h : result.is_ok (@result.error α it cache msg stx eps)) : false :=
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match h with end
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@[inline] def unreachable_error {α β : Type} {it : iterator} {cache : parser_cache} {msg : string} {stx : syntax} {eps : bool}
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(h : result.is_ok (@result.error α it cache msg stx eps)) : β :=
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false.elim (error_is_not_ok h)
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def result_ok (α : Type) := {r : result α // r.is_ok}
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@[inline] def mk_result_ok {α : Type} (a : α) (it : iterator) (cache : parser_cache) (state : parser_state) (eps : bool) : result_ok α :=
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⟨result.ok a it cache state eps, result.is_ok.mk _ _ _ _ _⟩
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def parser_core_m (α : Type) :=
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parser_config → result_ok unit → result α
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abbreviation parser_core := parser_core_m syntax
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structure rec_parsers :=
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(cmd_parser : parser_core)
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(lvl_parser : nat → parser_core)
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(term_parser : nat → parser_core)
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def parser_m (α : Type) := rec_parsers → parser_core_m α
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abbreviation parser := parser_m syntax
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abbreviation trailing_parser := syntax → parser
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@[inline] def command.parser : parser := λ ps, ps.cmd_parser
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@[inline] def level.parser (rbp : nat := 0) : parser := λ ps, ps.lvl_parser rbp
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@[inline] def term.parser (rbp : nat := 0) : parser := λ ps, ps.term_parser rbp
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@[inline] def parser_m.pure {α : Type} (a : α) : parser_m α :=
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λ _ cfg r,
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match r with
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| ⟨result.ok _ it c s _, h⟩ := result.ok a it c s tt
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| ⟨result.error _ _ _ _ _, h⟩ := unreachable_error h
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@[inline_if_reduce] def eager_or (b₁ b₂ : bool) := b₁ || b₂
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@[inline_if_reduce] def eager_and (b₁ b₂ : bool) := b₁ && b₂
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@[inline] def parser_m.bind {α β : Type} (x : parser_m α) (f : α → parser_m β) : parser_m β :=
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λ ps cfg r,
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match x ps cfg r with
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| result.ok a it c s e₁ :=
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(match f a ps cfg (mk_result_ok () it c s e₁) with
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| result.ok b it c s e₂ := result.ok b it c s (eager_and e₁ e₂)
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| result.error it c msg stx e₂ := result.error it c msg stx (eager_and e₁ e₂))
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| result.error it c msg stx e := result.error it c msg stx e
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instance parser_m_is_monad : monad parser_m :=
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{pure := @parser_m.pure, bind := @parser_m.bind}
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def mk_error {α β : Type} (r : result_ok α) (msg : string) (stx : syntax := lean.parser.syntax.missing) : result β :=
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match r with
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| ⟨result.ok a it c s e, _⟩ := result.error it c msg stx tt
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| ⟨result.error _ _ _ _ _, h⟩ := unreachable_error h
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def cmd_not_allowed : parser_core :=
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λ cfg r, mk_error r "commands are not allowed here"
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def term_not_allowed : nat → parser_core :=
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λ rbp cfg r, mk_error r "terms are not allowed here"
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def rec_lvl (parse_lvl : nat → parser) : nat → nat → parser_core
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| 0 rbp cfg r := mk_error r "parser: no progress"
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| (n+1) rbp cfg r := parse_lvl rbp ⟨cmd_not_allowed, rec_lvl n, term_not_allowed⟩ cfg r
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mutual def rec_cmd, rec_term (parse_cmd : parser) (parse_term : nat → parser) (parse_lvl : nat → parser_core)
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with rec_cmd : nat → parser_core
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| 0 cfg r := mk_error r "parser: no progress"
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| (n+1) cfg r := parse_cmd ⟨rec_cmd n, parse_lvl, rec_term n⟩ cfg r
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with rec_term : nat → nat → parser_core
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| 0 rbp cfg r := mk_error r "parser: no progress"
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| (n+1) rbp cfg r := parse_term rbp ⟨rec_cmd n, parse_lvl, rec_term n⟩ cfg r
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def run_parser (x : parser) (parse_cmd : parser) (parse_lvl : nat → parser) (parse_term : nat → parser)
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(input : iterator) (cfg : parser_config) : result syntax :=
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let it := input in
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let n := it.remaining in
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let r := mk_result_ok () it {} {messages := message_log.empty} tt in
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let pl := rec_lvl (parse_lvl) n in
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let ps : rec_parsers := { cmd_parser := rec_cmd parse_cmd parse_term pl n,
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lvl_parser := pl,
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term_parser := rec_term parse_cmd parse_term pl n } in
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x ps cfg r
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structure parsing_tables :=
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(leading_term_parsers : token_map parser)
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(trailing_term_parsers : token_map trailing_parser)
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abbreviation command_parser_m (α : Type) :=
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parsing_tables → parser_m α
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end flat_parser
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end lean
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def main : io uint32 :=
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io.println' "ok" *>
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pure 0
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