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unification seems to work for kovacs examples

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This commit is contained in:
Steve Dunham
2024-07-13 09:32:49 -07:00
parent b37fa56c70
commit 76fae34bcf
11 changed files with 219 additions and 136 deletions
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46
README.md
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@@ -12,45 +12,65 @@ So smalltt has TopVar with a Level. typechecking binders end up as top too.
Also delayed unfolded values for top or solved metas. This looks like glue - all the bits for the top and a cached value (it's keeping top as values).
We need metas next. SmallTT has a metactx in context as a mutable array.
REVIEW the delayed unfolding, we're being aggressive for now. This may have been necessary until unification was in place, now we can decide to further unfold during unification.
We extend the context and then drop it, so we need soemthing mutable.
metas are assoc list, can probably just be list, but we'd need to do level/index math for the lookup.
It's in top context and he pulls stuff down to context as needed. I'm overthinking this. I'm reluctant to copy Idris because resolved names are not compatible with query based, but everybody is using an array...
They are in separate MetaContext wrapped in an IORef. I'm reluctant to copy Idris because resolved names are not compatible with query based, but everybody is using an array...
I'd kinda like to see array run in js...
Idris has a common array for metas and defs but that might be a problem if I go query based someday.
Idris does a common array for metas and defs.
Prettier was missing a Lazy. I'm still fairly faithful to the paper, but might want to refactor that to push the computation down into the `if`.
Prettier was missing a Lazy.
Zoo3 runs now, I had to fix meta / meta unification.
Zoo3, mostly runs aside from eqTest.
I've added a bunch of info logs for the editor support.
Zoo4 examples run now.
Maybe do `data` next. There is a crude version in place, we'll want to fix that, typecheck the new stuff, and then add cases. (Maybe introduce eliminators.)
When I generate code, I'll eventually run up against the erased thing. (I'll want to erase some of the stuff that is compile time.) But we'll generate code and decide how far we need to take this. It's probably pointless to just reproduce Idris.
When I self host, I'll have to drop or implement typeclasses. I do understand auto enough to make it happen.
Ok, for code gen, I think I'll need something like primitive values and definitely primitive functions. For v0, I could leave the holes as undefined and if there is a function with that name, it's magically FFI.
Questions:
- [ ] Code gen or data next?
- [ ] Should I write this up properly?
Parser:
- [x] unify broken for zoo3 `cons`
- [ ] parser for block comments
- [x] import statement
- [x] def
- [x] simple decl
- [x] List not in scope
Misc:
- [x] vscode support for .newt
- [ ] Should I switch this back over to the App monad?
- [x] Error object like pi-forall
- [ ] Get implicits working
- [ ] I think I'll need to go with non-generic error type once I need to do something other than print them
- [x] Get unification working (zoo3)
- [x] Get implicits working (zoo4)
- [x] Replace on define
- [x] more sugar on lambdas
- [ ] tests for parsing and pretty printing
- [ ] white box tests for internals
- Maybe look at narya for examples of what I should be testing
- [ ] inductive types
- [ ] read data definitions 1/2 done
- read data definitions 1/2 done
- [x] read files
- [x] process a file
- [x] figure out context representation - Global context?
- [x] type checking / elab
- What does this represent? The basics, implicits? pattern unification?
- [ ] symbolic execution
- why did I put this here? Is it just for `eval`? We do have CBN in place, we could eval inferrable
- [ ] compilation
- I'm thinking I get data working first
- [ ] write tests
- [ ] Split up code better
Forward:

6
newt-vscode/src/extension.ts
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@@ -27,9 +27,9 @@ export function activate(context: vscode.ExtensionContext) {
for (let i = 0; i < lines.length; i++) {
const line = lines[i];
const match = line.match(/ERROR at \((\d+), (\d+)\): (.*)/);
const match = line.match(/(INFO|ERROR) at \((\d+), (\d+)\): (.*)/);
if (match) {
let [_full, line, column, message] = match;
let [_full, kind, line, column, message] = match;
let lnum = Number(line);
let cnum = Number(column);
let start = new vscode.Position(lnum, cnum);
@@ -47,7 +47,7 @@ export function activate(context: vscode.ExtensionContext) {
) {
message += "\n" + lines[++i];
}
const severity = vscode.DiagnosticSeverity.Error;
const severity = kind === 'ERROR' ? vscode.DiagnosticSeverity.Error : vscode.DiagnosticSeverity.Information
const diag = new vscode.Diagnostic(range, message, severity);
diagnostics.push(diag);
}

22
newt/zoo3.newt
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@@ -54,23 +54,5 @@ hundred = mul ten ten
thousand : Nat
thousand = mul ten hundred
-- All of these fail, but are they funext?
-- works for zoo3, but maybe I'm expanding stuff too eagerly
-- eq : Eq _ true true
-- eq = refl
-- eqTest2 : Eq _ five five
-- eqTest2 = refl
-- -- This one breaks
-- eqTest : Eq _ hundred hundred
-- -- eqTest = refl _ _
-- Add the rest
-- unify (%pi _ E (%var 3 []) (%cl [(%var 6 []), (%var 3 []), (%var 0 []), (%var 2 []), (%var 1 []), (%var 0 [])] (Bnd 2))) with
-- (%pi _ E (%var 2 []) (%cl [(%var 6 []), (%var 2 []), (%var 0 []), (%var 1 []), (%var 0 [])] (Bnd 2)))
-- -> (%pi _ E (%var 3 []) (%cl [(%var 6 []), (%var 3 []), (%var 0 []), (%var 2 []), (%var 1 []), (%var 0 [])] (Bnd 2))) with
-- (%pi _ E (%var 2 []) (%cl [(%var 6 []), (%var 2 []), (%var 0 []), (%var 1 []), (%var 0 [])] (Bnd 2)))
eqTest : Eq _ hundred hundred
eqTest = refl _ _

119
src/Lib/Check.idr
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@@ -21,7 +21,7 @@ data PRen = PR Nat Nat (List Nat)
forceMeta : Val -> M Val
-- TODO - need to look up metas
forceMeta (VMeta ix sp) = case !(lookupMeta ix) of
(Unsolved k xs) => pure (VMeta ix sp)
(Unsolved pos k xs) => pure (VMeta ix sp)
(Solved k t) => vappSpine t sp
forceMeta x = pure x
@@ -63,7 +63,7 @@ rename meta ren lvl v = go ren lvl v
lams : Nat -> Tm -> Tm
lams 0 tm = tm
lams (S k) tm = Lam "arg\{show k}" Explicit (lams k tm)
lams (S k) tm = Lam "arg:\{show k}" Explicit (lams k tm)
solve : Nat -> Nat -> SnocList Val -> Val -> M ()
solve l m sp t = do
@@ -75,15 +75,19 @@ solve l m sp t = do
solveMeta top m soln
pure ()
unify : (l : Nat) -> Val -> Val -> M ()
parameters (ctx: Context)
unify : (l : Nat) -> Val -> Val -> M ()
unifySpine : Nat -> Bool -> SnocList Val -> SnocList Val -> M ()
unifySpine l False _ _ = throwError $ E (0,0) "unify failed"
unifySpine l True [<] [<] = pure ()
unifySpine l True (xs :< x) (ys :< y) = unify l x y >> unifySpine l True xs ys
unifySpine l True _ _ = throwError $ E (0,0) "meta spine length mismatch"
unifySpine : Nat -> Bool -> SnocList Val -> SnocList Val -> M ()
unifySpine l False _ _ = error [DS "unify failed at head"] -- unreachable now
unifySpine l True [<] [<] = pure ()
unifySpine l True (xs :< x) (ys :< y) = unify l x y >> unifySpine l True xs ys
unifySpine l True _ _ = error [DS "meta spine length mismatch"]
unify l t u = do
unify l t u = do
putStrLn "Unify \{show ctx.lvl}"
putStrLn " \{show l} \{show t}"
putStrLn " =?= \{show u}"
t' <- forceMeta t
u' <- forceMeta u
case (t',u') of
@@ -91,37 +95,68 @@ unify l t u = do
(t, VLam _ _ t' ) => unify (l + 1) !(t `vapp` VVar l [<]) !(t' $$ VVar l [<])
(VLam _ _ t, t' ) => unify (l + 1) !(t $$ VVar l [<]) !(t' `vapp` VVar l [<])
(VPi _ _ a b, VPi _ _ a' b') => unify l a a' >> unify (S l) !(b $$ VVar l [<]) !(b' $$ VVar l [<])
(VVar k sp, VVar k' sp' ) => unifySpine l (k == k') sp sp'
(VRef n sp, VRef n' sp' ) => unifySpine l (n == n') sp sp'
(VMeta i sp, VMeta i' sp' ) => unifySpine l (i == i') sp sp'
(VVar k sp, VVar k' sp' ) =>
if k == k' then unifySpine l (k == k') sp sp'
else error [DS "vvar mismatch \{show k} \{show k'}"]
(VRef k sp, VRef k' sp' ) =>
if k == k' then unifySpine l (k == k') sp sp'
else error [DS "vref mismatch \{show k} \{show k'}"]
(VMeta k sp, VMeta k' sp' ) =>
if k == k' then unifySpine l (k == k') sp sp'
else solve l k sp (VMeta k' sp')
(t, VMeta i' sp') => solve l i' sp' t
(VMeta i sp, t' ) => solve l i sp t'
(VU, VU) => pure ()
_ => throwError $ E (0,0) "unify failed"
-- REVIEW consider quoting back
_ => error [DS "unify failed", DS (show t'), DS "=?=", DS (show u') ]
insert : (ctx : Context) -> Tm -> Val -> M (Tm, Val)
insert ctx tm ty = do
case !(forceMeta ty) of
VPi x Implicit a b => do
m <- freshMeta ctx
mv <- eval ctx.env CBN m
insert ctx (App tm m) !(b $$ mv)
va => pure (tm, va)
export
infer : Context -> Raw -> M (Tm, Val)
export
check : Context -> Raw -> Val -> M Tm
check ctx (RSrcPos x tm) ty = check ({pos := x} ctx) tm ty
check ctx (RLam nm icit tm) ty = case ty of
(VPi pinm icit a b) => do
-- TODO icit
check ctx tm ty with (force ty)
check ctx (RSrcPos x tm) _ | ty = check ({pos := x} ctx) tm ty
check ctx t@(RLam nm icit tm) _ | ty = case ty of
(VPi nm' icit' a b) => do
putStrLn "icits \{nm} \{show icit} \{nm'} \{show icit'}"
if icit == icit' then do
let var = VVar (length ctx.env) [<]
let ctx' = extend ctx nm a
tm' <- check ctx' tm !(b $$ var)
pure $ Lam nm icit tm'
else if icit' == Implicit then do
let var = VVar (length ctx.env) [<]
ty' <- b $$ var
sc <- check (extend ctx nm' a) t ty'
pure $ Lam nm' icit' sc
else
error [(DS "Icity issue checking \{show t} at \{show ty}")]
other => error [(DS "Expected pi type, got \{show !(quote 0 ty)}")]
check ctx tm ty = do
(tm', ty') <- infer ctx tm
-- This is where the conversion check / pattern unification go
unify ctx.lvl ty' ty
-- if quote 0 ty /= quote 0 ty' then
-- error [DS "type mismatch got", DD (quote 0 ty'), DS "expected", DD (quote 0 ty)]
-- else pure tm'
check ctx tm _ | (VPi nm' Implicit a b) = do
putStrLn "XXX edge \{show tm} against VPi"
let var = VVar (length ctx.env) [<]
ty' <- b $$ var
sc <- check (extend ctx nm' a) tm ty'
pure $ Lam nm' Implicit sc
check ctx tm _ | ty = do
-- We need to insert if it's not a Lam
-- TODO figure out why the exception is here (cribbed from kovacs)
(tm', ty') <- case !(infer ctx tm) of
(tm'@(Lam{}),ty') => pure (tm', ty')
(tm', ty') => insert ctx tm' ty'
putStrLn "infer \{show tm} to \{show tm'} : \{show ty'} expect \{show ty}"
when( ctx.lvl /= length ctx.env) $ error [DS "level mismatch \{show ctx.lvl} \{show ctx.env}"]
unify ctx ctx.lvl ty' ty
pure tm'
infer ctx (RVar nm) = go 0 ctx.types
@@ -136,12 +171,31 @@ infer ctx (RVar nm) = go 0 ctx.types
-- need environment of name -> type..
infer ctx (RApp t u icit) = do
-- icit will be used for insertion, lets get this working first...
(icit, t, tty) <- case the Icit icit of
Explicit => do
(t, tty) <- infer ctx t
case tty of
(VPi str icit' a b) => do
(t, tty) <- insert ctx t tty
pure (Explicit, t, tty)
Implicit => do
(t, tty) <- infer ctx t
pure (Implicit, t, tty)
(a,b) <- case !(forceMeta tty) of
(VPi str icit' a b) => if icit' == icit then pure (a,b)
else error [DS "IcitMismatch \{show icit} \{show icit'}"]
-- If it's not a VPi, try to unify it with a VPi
tty => do
putStrLn "unify PI for \{show tty}"
a <- eval ctx.env CBN !(freshMeta ctx)
b <- MkClosure ctx.env <$> freshMeta (extend ctx "x" ?hole)
unify ctx 0 tty (VPi "x" icit a b)
pure (a,b)
u <- check ctx u a
pure (App t u, !(b $$ !(eval ctx.env CBN u)))
_ => error [DS "Expected Pi type"]
infer ctx RU = pure (U, VU) -- YOLO
infer ctx (RPi nm icit ty ty2) = do
ty' <- check ctx ty VU
@@ -157,7 +211,14 @@ infer ctx (RAnn tm rty) = do
tm <- check ctx tm vty
pure (tm, vty)
infer ctx (RLam str icit tm) = error [DS "can't infer lambda"]
infer ctx (RLam nm icit tm) = do
a <- freshMeta ctx >>= eval ctx.env CBN
let ctx' = extend ctx nm a
(tm', b) <- infer ctx' tm
putStrLn "make lam for \{show nm} scope \{show tm'} : \{show b}"
pure $ (Lam nm icit tm', VPi nm icit a $ MkClosure ctx.env !(quote (S ctx.lvl) b))
-- error {ctx} [DS "can't infer lambda"]
infer ctx RHole = do
ty <- freshMeta ctx
vty <- eval ctx.env CBN ty

8
src/Lib/Parser.idr
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@@ -14,6 +14,7 @@ import Lib.Token
import Lib.Parser.Impl
import Syntax
import Data.List
import Data.Maybe
-- There is the whole core vs surface thing here.
-- might be best to do core first/ Technically don't
@@ -186,10 +187,11 @@ ibind : Parser (List (String, Icit, Raw))
ibind = do
sym "{"
names <- some ident
sym ":"
ty <- typeExpr
ty <- optional (sym ":" >> typeExpr)
pos <- getPos
sym "}"
pure $ map (\name => (name, Explicit, ty)) names
-- getPos is a hack here, I would like to position at the name...
pure $ map (\name => (name, Implicit, fromMaybe (RSrcPos pos RHole) ty)) names
-- Collect a bunch of binders (A : U) {y : A} -> ...
binders : Parser Raw

2
src/Lib/Parser/Impl.idr
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@@ -125,7 +125,7 @@ pred : (BTok -> Bool) -> String -> Parser String
pred f msg = P $ \toks,com,col =>
case toks of
(t :: ts) => if f t then OK (value t) ts com else Fail False (error toks "\{msg} vt:\{value t}") toks com
[] => Fail False (error toks "eof") toks com
[] => Fail False (error toks "\{msg} at EOF") toks com
export
commit : Parser ()

1
src/Lib/Prettier.idr
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@@ -13,6 +13,7 @@ export
data Doc = Empty | Line | Text String | Nest Nat Doc | Seq Doc Doc | Alt Doc Doc
||| `DOC` is an intermediate form used during layout/rendering
||| The capitalization is the opposite of the paper.
data DOC = EMPTY | TEXT String DOC | LINE Nat DOC
flatten : Doc -> Doc

19
src/Lib/TT.idr
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@@ -3,6 +3,9 @@
-- maybe watch https://www.youtube.com/watch?v=3gef0_NFz8Q
-- or drop the indices for now.
-- ***
-- Kovacs has icity on App, and passes it around, but I'm not sure where it is needed since the insertion happens based on Raw.
module Lib.TT
-- For SourcePos
import Lib.Parser.Impl
@@ -34,17 +37,21 @@ export
error' : String -> M a
error' msg = throwError $ E (0,0) msg
-- order does indeed matter on the meta arguments
-- because of dependent types (if we want something well-typed back out)
export
freshMeta : Context -> M Tm
freshMeta ctx = do
mc <- readIORef ctx.metas
writeIORef ctx.metas $ { next $= S, metas $= (Unsolved mc.next ctx.bds ::) } mc
putStrLn "INFO at \{show ctx.pos}: fresh meta \{show mc.next}"
writeIORef ctx.metas $ { next $= S, metas $= (Unsolved ctx.pos mc.next ctx.bds ::) } mc
pure $ applyBDs 0 (Meta mc.next) ctx.bds
where
-- hope I got the right order here :)
applyBDs : Nat -> Tm -> List BD -> Tm
applyBDs k t [] = t
-- review the order here
applyBDs k t (Bound :: xs) = App (applyBDs (S k) t xs) (Bnd k)
applyBDs k t (Defined :: xs) = applyBDs (S k) t xs
@@ -57,7 +64,7 @@ lookupMeta ix = do
where
go : List MetaEntry -> M MetaEntry
go [] = error' "Meta \{show ix} not found"
go (meta@(Unsolved k ys) :: xs) = if k == ix then pure meta else go xs
go (meta@(Unsolved _ k ys) :: xs) = if k == ix then pure meta else go xs
go (meta@(Solved k x) :: xs) = if k == ix then pure meta else go xs
export
@@ -69,8 +76,10 @@ solveMeta ctx ix tm = do
where
go : List MetaEntry -> SnocList MetaEntry -> M (List MetaEntry)
go [] _ = error' "Meta \{show ix} not found"
go (meta@(Unsolved k _) :: xs) lhs = if k == ix
then pure $ lhs <>> (Solved k tm :: xs)
go (meta@(Unsolved pos k _) :: xs) lhs = if k == ix
then do
putStrLn "INFO at \{show pos}: solve \{show k} as \{show tm}"
pure $ lhs <>> (Solved k tm :: xs)
else go xs (lhs :< meta)
go (meta@(Solved k _) :: xs) lhs = if k == ix
then error' "Meta \{show ix} already solved!"
@@ -146,7 +155,7 @@ eval env mode (App t u) = vapp !(eval env mode t) !(eval env mode u)
eval env mode U = pure VU
eval env mode (Meta i) =
case !(lookupMeta i) of
(Unsolved k xs) => pure $ VMeta i [<]
(Unsolved _ k xs) => pure $ VMeta i [<]
(Solved k t) => pure $ t
eval env mode (Lam x icit t) = pure $ VLam x icit (MkClosure env t)
eval env mode (Pi x icit a b) = pure $ VPi x icit !(eval env mode a) (MkClosure env b)

24
src/Lib/Types.idr
View File

@@ -28,6 +28,11 @@ data Icit = Implicit | Explicit
%name Icit icit
export
Show Icit where
show Implicit = "Implicit"
show Explicit = "Explicit"
public export
data BD = Bound | Defined
@@ -41,6 +46,7 @@ data Tm : Type where
-- kovacs optimization, I think we can App out meta instead
-- InsMeta : Nat -> List BD -> Tm
Lam : Name -> Icit -> Tm -> Tm
-- Do we need to remember Icit here?
App : Tm -> Tm -> Tm
U : Tm
Pi : Name -> Icit -> Tm -> Tm -> Tm
@@ -57,7 +63,8 @@ Show Tm where
show (App t u) = "(\{show t} \{show u})"
show (Meta i) = "(Meta \{show i})"
show U = "U"
show (Pi str icit t u) = "(∏ \{str} : \{show t} => \{show u})"
show (Pi str Implicit t u) = "(Pi (\{str} : \{show t}) => \{show u})"
show (Pi str Explicit t u) = "(Pi {\{str} : \{show t}} => \{show u})"
show (Let str icit t u v) = "let \{str} : \{show t} = \{show u} in \{show v}"
-- I can't really show val because it's HOAS...
@@ -126,9 +133,6 @@ data Val : Type where
VPi : Name -> Icit -> Lazy Val -> Closure -> Val
VU : Val
Show Icit where
show Implicit = "I"
show Explicit = "E"
Show Closure
@@ -138,7 +142,8 @@ Show Val where
show (VRef nm sp) = "(%ref \{nm} \{show sp})"
show (VMeta ix sp) = "(%meta \{show ix} \{show sp})"
show (VLam str icit x) = "(%lam \{str} \{show icit} \{show x})"
show (VPi str icit x y) = "(%pi \{str} \{show icit} \{show x} \{show y})"
show (VPi str Implicit x y) = "(%pi {\{str} : \{show x}}. \{show y})"
show (VPi str Explicit x y) = "(%pi (\{str} : \{show x}). \{show y})"
show VU = "U"
public export
@@ -182,9 +187,14 @@ Can I get val back? Do we need to quote? What happens if we don't?
-}
-- FIXME remove List BD
public export
data MetaEntry = Unsolved Nat (List BD) | Solved Nat Val
data MetaEntry = Unsolved SourcePos Nat (List BD) | Solved Nat Val
export
covering
Show MetaEntry where
show (Unsolved pos k xs) = "Unsolved \{show pos} \{show k}"
show (Solved k x) = "Solved \{show k} \{show x}"
public export
record MetaContext where

3
src/Main.idr
View File

@@ -48,6 +48,7 @@ dumpContext top = do
processDecl : Decl -> M ()
processDecl (TypeSig nm tm) = do
top <- get
putStrLn "-----"
putStrLn "TypeSig \{nm} \{show tm}"
ty <- check (mkCtx top.metas) tm VU
putStrLn "got \{show ty}"
@@ -55,6 +56,7 @@ processDecl (TypeSig nm tm) = do
-- FIXME - this should be in another file
processDecl (Def nm raw) = do
putStrLn "-----"
putStrLn "def \{show nm}"
ctx <- get
let pos = case raw of
@@ -67,6 +69,7 @@ processDecl (Def nm raw) = do
| _ => throwError $ E pos "\{nm} already defined"
putStrLn "check \{nm} = \{show raw} at \{show $ ty}"
vty <- eval empty CBN ty
putStrLn "vty is \{show vty}"
tm <- check (mkCtx ctx.metas) raw vty
putStrLn "Ok \{show tm}"
put (addDef ctx nm tm ty)

5
src/Syntax.idr
View File

@@ -114,11 +114,6 @@ Show Pattern where
Show CaseAlt where
show (MkAlt x y)= foo ["MkAlt", show x, assert_total $ show y]
Show Icit where
show Implicit = "Implicit"
show Explicit = "Explicit"
-- show Eq = "Eq"
covering
Show Raw where
show RHole = "_"