92 lines
2.7 KiB
Text
92 lines
2.7 KiB
Text
/-
|
||
Copyright (c) 2018 Microsoft Corporation. All rights reserved.
|
||
Released under Apache 2.0 license as described in the file LICENSE.
|
||
Author: Sebastian Ullrich
|
||
|
||
Reader for the Lean language
|
||
-/
|
||
prelude
|
||
import init.lean.parser.parsec init.lean.parser.syntax init.lean.parser.macro
|
||
import init.lean.parser.identifier
|
||
|
||
namespace lean
|
||
-- TODO: enhance massively
|
||
def message := string
|
||
|
||
namespace parser
|
||
|
||
structure token_config :=
|
||
(«prefix» : string)
|
||
-- reading a token should not need any state
|
||
/- An optional parser that is activated after matching `prefix`.
|
||
It should return a syntax tree with a "hole" for the
|
||
`source_info` surrounding the token, which will be supplied
|
||
by the `token` reader. -/
|
||
(token_reader : option (parsec (source_info → syntax)) := none)
|
||
|
||
structure reader_state :=
|
||
(tokens : list token_config)
|
||
(fatal : bool)
|
||
(errors : list lean.message)
|
||
|
||
def reader_state.empty : reader_state :=
|
||
⟨[], ff, []⟩
|
||
|
||
structure reader_config := mk
|
||
|
||
@[irreducible] def read_m := reader_t reader_config $ state_t reader_state $ parsec
|
||
|
||
structure reader :=
|
||
(read : read_m syntax)
|
||
(tokens : list token_config := [])
|
||
|
||
namespace read_m
|
||
local attribute [reducible] read_m
|
||
instance : monad read_m := infer_instance
|
||
instance : alternative read_m := infer_instance
|
||
instance : monad_reader reader_config read_m := infer_instance
|
||
instance : monad_state reader_state read_m := infer_instance
|
||
instance : monad_parsec read_m := infer_instance
|
||
|
||
--TODO(Sebastian): expose `reader_state.errors`
|
||
protected def run {α : Type} (cfg : reader_config) (st : reader_state) (s : string) (r : read_m α) :
|
||
except parser.message α :=
|
||
prod.fst <$> ((r.run cfg).run st).parse_with_eoi s
|
||
end read_m
|
||
|
||
namespace reader
|
||
open monad_parsec
|
||
|
||
protected def parse (cfg : reader_config) (s : string) (r : reader) :
|
||
except parser.message syntax :=
|
||
-- the only hardcoded tokens, because they are never directly mentioned by a `reader`
|
||
let tokens : list token_config := [⟨"/-", none⟩, ⟨"--", none⟩] in
|
||
r.read.run cfg ⟨r.tokens ++ tokens, ff, []⟩ s
|
||
|
||
def node (m : macro) (ps : list reader) : reader :=
|
||
{ read := do {
|
||
args ← ps.mmap reader.read,
|
||
pure $ syntax.node ⟨m.name, args⟩
|
||
},
|
||
tokens := ps.bind reader.tokens }
|
||
|
||
def many (p : reader) : reader :=
|
||
{ p with read := do
|
||
args ← many p.read,
|
||
pure $ syntax.node ⟨name.anonymous, args⟩ }
|
||
|
||
def many1 (p : reader) : reader :=
|
||
{ p with read := do
|
||
args ← many1 p.read,
|
||
pure $ syntax.node ⟨name.anonymous, args⟩ }
|
||
|
||
def optional (p : reader) : reader :=
|
||
{ p with read := do
|
||
r ← optional p.read,
|
||
pure $ match r with
|
||
| some r := syntax.node ⟨name.anonymous, [r]⟩
|
||
| none := syntax.node ⟨name.anonymous, []⟩ }
|
||
|
||
end reader
|
||
end parser
|
||
end lean
|