Start getting examples working again

4 files changed, 53 insertions, 46 deletions

diff --git a/lib/parser.dx b/lib/parser.dx
index 1ca78095..e1d6e092 100644
--- a/lib/parser.dx
+++ b/lib/parser.dx
@@ -11,7 +11,7 @@ def from_ordinal_exc(n|Ix, i:Nat) -> {Except} n =
 
 # TODO: allow this to happen in-place
 # TODO: if it takes too long to make that possible, start with a bounded version
-def push(ref:Ref h (List a), x:a) -> {State h} () given (h, a|Data) =
+def push(ref:Ref h (List a), x:a) -> {State h} () given (h:Heap, a|Data) =
   l = get ref
   ref := l <> AsList _ [x]
 
@@ -28,11 +28,11 @@ struct ParserHandle(h:Heap) =
 enum Parser(a:Type) =
   MkParser((given(h:Heap), ParserHandle h )-> {Except, State h} a)
 
-def parse(handle:ParserHandle h, parser:Parser a) -> {Except, State h} a given (a, h)  =
+def parse(handle:ParserHandle h, parser:Parser a) -> {Except, State h} a given (a:Type, h:Heap)  =
   MkParser f = parser
   f handle
 
-def run_parser_partial(s:String, parser:Parser a) -> Maybe a given (a)  =
+def run_parser_partial(s:String, parser:Parser a) -> Maybe a given (a:Type)  =
   MkParser f = parser
   with_state 0 \pos.
     catch $ \.
@@ -49,7 +49,7 @@ def p_char(c:Char) -> Parser () = MkParser \h.
 def p_eof() ->> Parser () = MkParser \h.
   assert $ get h.offset >= list_length h.input
 
-def (<|>)(p1:Parser a, p2:Parser a) -> Parser a given (a) = MkParser \h.
+def (<|>)(p1:Parser a, p2:Parser a) -> Parser a given (a:Type) = MkParser \h.
   curPos = get h.offset
   case catch \. parse h p1 of
     Nothing ->
@@ -57,9 +57,9 @@ def (<|>)(p1:Parser a, p2:Parser a) -> Parser a given (a) = MkParser \h.
       parse h p2
     Just ans -> ans
 
-def returnP(x:a) -> Parser a given (a) = MkParser \_. x
+def returnP(x:a) -> Parser a given (a:Type) = MkParser \_. x
 
-def run_parser(s:String, parser:Parser a) -> Maybe a given (a) =
+def run_parser(s:String, parser:Parser a) -> Maybe a given (a:Type) =
   run_parser_partial s $ MkParser \h.
     ans = parse h parser
     _   = parse h p_eof
@@ -79,7 +79,7 @@ def parse_anything_but(c:Char) -> Parser Char =
     h.offset := i + 1
     c'
 
-def try(parser:Parser a) -> Parser a given (a) = MkParser \h.
+def try(parser:Parser a) -> Parser a given (a:Type) = MkParser \h.
   savedPos = get h.offset
   ans = catch \. parse h parser
   case ans of
@@ -93,14 +93,14 @@ def try(parser:Parser a) -> Parser a given (a) = MkParser \h.
 def parse_digit() ->> Parser Int = try $ MkParser \h.
   c = parse h $ parse_any
   i = w8_to_i c - 48
-  assert $ 0 <= i && i < 10
+  assert $ (0::Int) <= i && i < 10
   i
 
-def optional(p:Parser a) -> Parser (Maybe a) given (a) =
+def optional(p:Parser a) -> Parser (Maybe a) given (a:Type) =
   (MkParser \h. Just (parse h p)) <|> returnP Nothing
 
 def parse_many(parser:Parser a) -> Parser (List a) given (a|Data) = MkParser \h.
-  yield_state (AsList _ []) \results.
+  yield_state mempty \results.
     iter \_.
       maybeVal = parse h $ optional parser
       case maybeVal of
@@ -118,7 +118,7 @@ def parse_some(parser:Parser a) -> Parser (List a) given (a|Data) =
 def parse_unsigned_int() ->> Parser Int = MkParser \h.
   AsList(_, digits) = parse h $ parse_many parse_digit
   yield_state 0 \ref.
-    for i. ref := 10 * get ref + digits[i]
+    each digits \digit. ref := 10 * get ref + digit
 
 def parse_int() ->> Parser Int = MkParser \h.
   negSign = parse h $ optional $ p_char '-'
@@ -127,18 +127,18 @@ def parse_int() ->> Parser Int = MkParser \h.
     Nothing -> x
     Just () -> (-1) * x
 
-def bracketed(l:Parser (), r:Parser (), body:Parser a) -> Parser a given (a) =
+def bracketed(l:Parser (), r:Parser (), body:Parser a) -> Parser a given (a:Type) =
   MkParser \h.
     _   = parse h l
     ans = parse h body
     _   = parse h r
     ans
 
-def parens(parser:Parser a) -> Parser a given (a) =
+def parens(parser:Parser a) -> Parser a given (a:Type) =
   bracketed (p_char '(') (p_char ')') parser
 
 def split(space:Char, s:String) -> List String =
-  def trailing_spaces(space:Parser (), body:Parser a) -> Parser a given (a) =
+  def trailing_spaces(space:Parser (), body:Parser a) -> Parser a given (a:Type) =
     MkParser \h.
       ans = parse h body
       _   = parse h $ parse_many space
@@ -148,4 +148,4 @@ def split(space:Char, s:String) -> List String =
     parse h $ parse_many (trailing_spaces (p_char space) (parse_some (parse_anything_but space)))
   case run_parser s split_parser of
     Just l -> l
-    Nothing -> AsList _ []
+    Nothing -> mempty
diff --git a/lib/stats.dx b/lib/stats.dx
index 3ee8cc17..fabf8d89 100644
--- a/lib/stats.dx
+++ b/lib/stats.dx
@@ -20,10 +20,10 @@ actual value being represented (the raw probability) can be computed with
  use `ls_sum`, which applies the standard max-sweep log-sum-exp trick directly,
 rather than relying on monoid reduction using `add`.
 
-struct LogSpace(a) =
+struct LogSpace(a:Type) =
   log : a
 
-def Exp(x:a) -> LogSpace a given (a) = LogSpace x
+def Exp(x:a) -> LogSpace a given (a:Type) = LogSpace x
 
 instance Mul(LogSpace f) given (f|Add)
   def (*)(x, y) = Exp $ x.log + y.log
@@ -38,14 +38,14 @@ instance Arbitrary(LogSpace Float)
 def is_infinite(x:f) -> Bool given (f|Fractional|Sub|Mul|Ord) =
   # Note: According to this function, nan is not infinite.
   # Todo: Make polymorphic versions of these and put them in the prelude.
-  infinity = divide one zero
-  neg_infinity = zero - infinity
+  infinity     : f = divide one zero
+  neg_infinity : f = zero - infinity
   x == infinity || x == neg_infinity
 
 def log_add_exp(la:f, lb:f) -> f
     given (f|Floating|Add|Sub|Mul|Fractional|Ord) =
-  infinity = (divide one zero)
-  neg_infinity = zero - infinity
+  infinity     : f = divide(one, zero)
+  neg_infinity : f = zero - infinity
   if la == infinity && lb == infinity
     then infinity
     else if la == neg_infinity && lb == neg_infinity
@@ -66,27 +66,29 @@ def ln(x:LogSpace f) -> f given (f|Floating) = x.log
 
 def log_sum_exp(xs:n=>f) -> f
     given(n|Ix, f|Fractional|Sub|Floating|Mul|Ord) =
-  m_raw = maximum xs
-  m = case is_infinite m_raw of
+  m_raw = maximum(xs)
+  m = case is_infinite(m_raw) of
     False -> m_raw
     True  -> zero
-  m + (log $ sum for i. exp (xs[i] - m))
+  m + (log $ sum $ each xs \x. exp(x) - m)
 
 def ls_sum(x:n=>LogSpace f) -> LogSpace f
     given (n|Ix, f|Fractional|Sub|Floating|Mul|Ord) =
-  lx = map ln x
+  lx = each(x, ln)
   Exp $ log_sum_exp lx
 
 '## Probability distributions
 Simulation and evaluation of [probability distributions](https://en.wikipedia.org/wiki/Probability_distribution). Probability distributions which can be sampled should implement `Random`, and those which can be evaluated should implement the `Dist` interface. Distributions over an ordered space (such as typical *univariate* distributions) should also implement `OrderedDist`.
 
-interface Random(d, a)
+# TODO: use an associated type for the `a` parameter
+interface Random(d:Type, a:Type)
   draw : (d, Key) -> a                # function for random draws
 
-interface Dist(d, a, f)
+# TODO: use an associated type for the `a` parameter
+interface Dist(d:Type, a:Type, f:Type)
   density : (d, a) -> LogSpace f      # either the density function or mass function
 
-interface OrderedDist(d, a, f, given () (Dist d a f))
+interface OrderedDist(d:Type, a:Type, f:Type, given () (Dist d a f))
   cumulative : (d, a) -> LogSpace f   # the cumulative distribution function (CDF)
   survivor   : (d, a) -> LogSpace f   # the survivor function (complement of CDF)
   quantile   : (d, f) -> a            # the quantile function (inverse CDF)
@@ -131,7 +133,7 @@ struct Binomial =
 
 instance Random(Binomial, Nat)
   def draw(d, k) =
-    sum $ map b_to_n (rand_vec d.trials (\k_. draw(Bernoulli(d.prob), k_)) k)
+    sum $ each (rand_vec d.trials (\k_. draw(a=Bool, Bernoulli(d.prob), k_)) k) b_to_n
 
 instance Dist(Binomial, Nat, Float)
   def density(d, x) =
@@ -157,13 +159,13 @@ instance Dist(Binomial, Nat, Float)
 instance OrderedDist(Binomial, Nat, Float)
   def cumulative(d, x) =
     xp1:Nat = x + 1
-    ls_sum $ for i:(Fin xp1). density d (ordinal i)
+    ls_sum $ for i:(Fin xp1). density(f=Float, d, ordinal i)
   def survivor(d, x) =
     tmx = d.trials -| x
-    ls_sum $ for i:(Fin tmx). density d (x + 1 + ordinal i)
+    ls_sum $ for i:(Fin tmx). density(f=Float, d, x + 1 + ordinal i)
   def quantile(d, q) =
     tp1:Nat = d.trials + 1
-    lpdf = for i:(Fin tp1). ln $ density d (ordinal i)
+    lpdf = for i:(Fin tp1). ln $ density(f=Float, d, ordinal i)
     cdf = cdf_for_categorical lpdf
     mi = search_sorted cdf q
     ordinal $ from_just $ left_fence mi
@@ -257,13 +259,13 @@ struct Poisson =
 instance Random(Poisson, Nat)
   def draw(d, k) =
     exp_neg_rate = exp (-d.rate)
-    [current_k, next_k] = split_key k
+    [current_k, next_k] = split_key(n=2, k)
     yield_state 0 \ans.
       with_state (rand current_k) \p. with_state next_k \k'.
         while \.
           if get p > exp_neg_rate
             then
-              [ck, nk] = split_key (get k')
+              [ck, nk] = split_key(n=2, get k')
               p := (get p) * rand ck
               ans := (get ans) + 1
               k' := nk
@@ -283,16 +285,16 @@ instance Dist(Poisson, Nat, Float)
 instance OrderedDist(Poisson, Nat, Float)
   def cumulative(d, x) =
     xp1:Nat = x + 1
-    ls_sum $ for i:(Fin xp1). density d (ordinal i)
+    ls_sum $ for i:(Fin xp1). density(f=Float, d, ordinal i)
   def survivor(d, x) =
     xp1:Nat = x + 1
-    cdf = ls_sum $ for i:(Fin xp1). density d (ordinal i)
+    cdf = ls_sum $ for i:(Fin xp1). density(f=Float, d, ordinal i)
     Exp $ log1p (-ls_to_f cdf)
   def quantile(d, q) =
     yield_state (0::Nat) \x.
       with_state 0.0 \cdf.
         while \.
-          cdf := (get cdf) + ls_to_f (density d (get x))
+          cdf := (get cdf) + ls_to_f (density(f=Float, d ,get x))
           if (get cdf) > q
             then
               False
@@ -340,7 +342,7 @@ Some data summary functions. Note that `mean` is provided by the prelude.
 
 def mean_and_variance(xs:n=>a) -> (a, a) given (n|Ix, a|VSpace|Mul) =
   m = mean xs
-  ss = sum for i. sq (xs[i] - m)
+  ss = sum $ each xs \x. sq(x - m)
   v = ss / (n_to_f (size n) - 1)
   (m, v)
 
@@ -353,7 +355,7 @@ def std_dev(xs:n=>a) -> a given (n|Ix, a|VSpace|Mul|Floating) =
 def covariance(xs:n=>a, ys:n=>a) -> a given (n|Ix, a|VSpace|Mul) =
   xm = mean xs
   ym = mean ys
-  ss = sum for i. (xs[i] - xm) * (ys[i] - ym)
+  ss = sum for i:n. (xs[i] - xm) * (ys[i] - ym)
   ss / (n_to_f (size n) - 1)
 
 def correlation(xs:n=>a, ys:n=>a) -> a
@@ -364,8 +366,8 @@ def correlation(xs:n=>a, ys:n=>a) -> a
 
 def mean_and_variance_matrix(xs:n=>d=>a) -> (d=>a, d=>d=>a)
     given (n|Ix, d|Ix, a|Mul|VSpace) =
-  xsMean:d=>a = (for i. sum for j. xs[j,i]) / n_to_f (size n)
-  xsCov:d=>d=>a = (for i i'. sum for j.
+  xsMean:d=>a = (for i:d. sum for j:n. xs[j,i]) / n_to_f (size n)
+  xsCov:d=>d=>a = (for i:d i':d. sum for j:n.
                          (xs[j,i'] - xsMean[i']) *
                          (xs[j,i]  - xsMean[i] ) ) / (n_to_f (size n) - 1)
   (xsMean, xsCov)
diff --git a/makefile b/makefile
index baf3733a..1aa0f2af 100644
--- a/makefile
+++ b/makefile
@@ -215,11 +215,13 @@ example-names := \
   regression brownian_motion particle-swarm-optimizer \
   ode-integrator mcmc ctc raytrace particle-filter \
   fluidsim \
-  sgd psd kernelregression nn \
+  sgd nn \
   quaternions manifold-gradients schrodinger tutorial \
-  latex linear-maps dither mcts md bfgs
+  latex dither mcts md bfgs
+
 # TODO: re-enable
 # fft vega-plotting
+# examples depending on linalg: linear-maps, psd, kernelregression
 
 # Only test levenshtein-distance on Linux, because MacOS ships with a
 # different (apparently _very_ different) word list.
@@ -423,6 +425,9 @@ lib-files = $(filter-out lib/prelude.dx,$(wildcard lib/*.dx))
 pages-lib-files = $(patsubst %.dx,pages/%.html,$(lib-files))
 static-files = $(static-names:%=pages/static/%)
 
+serve-docs:
+	cd pages && python3 -m http.server
+
 docs: $(static-files) pages-prelude $(pages-doc-files) $(pages-example-files) $(pages-lib-files) $(slow-pages) pages/index.md
 
 pages/static/%: static/%
diff --git a/static/index.ts b/static/index.ts
index adf19ee6..11ee28fb 100644
--- a/static/index.ts
+++ b/static/index.ts
@@ -22,7 +22,7 @@ type HighlightType = "HighlightGroup" |  "HighlightLeaf" | "HighlightError" | "H
                    | "HighlightBinder" | "HighlightOcc"
 type Highlight    = [SrcId, HighlightType]
 
-type HsMaybe<T> = {tag:"Just"; contents:T} | {tag: "Nothing"}
+type HsMaybe<T> = T | null
 type HsOverwrite<T> = {tag:"OverwriteWith"; contents:T} | {tag: "NoChange"}
 
 type FocusMap = Map<LexemeId, SrcId>
@@ -249,8 +249,8 @@ function extendCellOutput(cell: Cell, outputs:HsRenderedOutput[]) {
                 break
             case "RenderedError":
                 const [maybeSrcId, errMsg] = output.contents
-                if (maybeSrcId.tag == "Just") {
-                    const node : TreeNode = cell.treeMap.get(maybeSrcId.contents) ?? oops()
+                if (maybeSrcId !== null) {
+                    const node : TreeNode = cell.treeMap.get(maybeSrcId) ?? oops()
                     highlightTreeNode(false, node, "HighlightError")}
                 addErrResult(cell, errMsg)
                 break