From 5d6916b20c3097558f21693c05a1d0293bea17a3 Mon Sep 17 00:00:00 2001
From: Anton <singaraiona@gmail.com>
Date: Sat, 13 Jun 2026 18:09:24 +0200
Subject: [PATCH] fix(iter): map-left/map-right iterate the named operand
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

map-left and map-right were defined by which argument is held fixed, the
inverse of the conventional model and the source of the long-standing
confusion (a scalar in the 'wrong' slot, or a lambda that does not
broadcast, gave surprising results). Redefine them by which operand is
ITERATED:

  map-left  — iterate the left operand,  hold the right whole → fn(left_i, right)
  map-right — iterate the right operand, hold the left whole  → fn(left, right_i)

The iterated side is fixed by the operator (no auto-detect heuristic).
When that side is an atom there is nothing to iterate, so fn is applied
once to (left, right); for an atomic builtin that single call is exactly
its broadcast, so map-left/map-right agree with plain application there.
Every call routes through call_fn2, so atomic builtins broadcast a held
vector element-wise and lambdas receive their arguments whole.

This swaps the prior meaning of the two ops. The window-join interval
idiom built its N per-row [lo hi] intervals with the old map-left;
that role is now map-right, so the join tests/docs are migrated
map-left -> map-right. Updates the map-left/map-right reference docs and
adds non-broadcasting lambda regression tests (a single concat /
list-building fn exposes the iteration structure that arithmetic
builtins' broadcast otherwise hides).
---
 docs/docs/language/functions.md          |  4 +--
 docs/docs/queries/joins.md               |  4 +--
 docs/docs/reference/all-functions.md     |  4 +--
 src/lang/eval.c                          |  4 +--
 src/ops/collection.c                     | 30 ++++++++++---------
 src/ops/query.c                          |  2 +-
 test/rfl/collection/cov2.rfl             | 25 ++++++++++++----
 test/rfl/integration/joins.rfl           | 38 ++++++++++++------------
 test/rfl/io/dump.rfl                     |  2 +-
 test/rfl/ops/exec_coverage.rfl           |  2 +-
 test/rfl/ops/opt_advanced.rfl            |  2 +-
 test/rfl/ops/opt_branch_cov.rfl          |  2 +-
 test/rfl/ops/query_coverage.rfl          |  4 +--
 test/rfl/query/query_branch_cov.rfl      |  2 +-
 test/rfl/query/query_update_coverage.rfl |  6 ++--
 test/rfl/table/update.rfl                |  2 +-
 16 files changed, 74 insertions(+), 59 deletions(-)

diff --git a/docs/docs/language/functions.md b/docs/docs/language/functions.md
index 546b0ba6..2b87d46b 100644
--- a/docs/docs/language/functions.md
+++ b/docs/docs/language/functions.md
@@ -93,8 +93,8 @@ Functions that take other functions as arguments.
 | `scan-left` | variadic | Left-to-right running fold | `(scan-left + (enlist 1 2 3))` → `[1 3 6]` |
 | `scan-right` | variadic | Right-to-left running fold | `(scan-right + (enlist 1 2 3))` → `[6 5 3]` |
 | `apply` | variadic | Zip-apply function pairwise over two lists | `(apply + (enlist 1 2) (enlist 3 4))` → `[4 6]` |
-| `map-left` | variadic | Map with left argument fixed | `(map-left + 10 [1 2 3])` → `[11 12 13]` |
-| `map-right` | variadic | Map with right argument fixed | `(map-right - [10 20 30] 5)` → `[5 15 25]` |
+| `map-left` | variadic | Map each element of the left over the whole right | `(map-left + 10 [1 2 3])` → `[11 12 13]` |
+| `map-right` | variadic | Map the whole left over each element of the right | `(map-right - [10 20 30] 5)` → `[5 15 25]` |
 
 ## Collection Operations
 
diff --git a/docs/docs/queries/joins.md b/docs/docs/queries/joins.md
index 3b674c55..0ded9636 100644
--- a/docs/docs/queries/joins.md
+++ b/docs/docs/queries/joins.md
@@ -185,7 +185,7 @@ Window join with per-row time intervals. `intervals` is a list of two vectors `[
           [928 528 648 914 918 626 577 817 620 698])))
 
 ; Build per-row intervals: [lo, hi] for each trade
-(set intervals (map-left + [-1000 1000] (at trades 'Time)))
+(set intervals (map-right + [-1000 1000] (at trades 'Time)))
 
 ; Window join: min bid and max ask within each window
 (window-join [Sym Time] intervals trades quotes
@@ -202,7 +202,7 @@ Window join with per-row time intervals. `intervals` is a list of two vectors `[
     (list bsym btime bid ask)))
 
 ; Build intervals from the trades timestamp
-(set intervals (map-left + [-1000 1000] (at trades 'Ts)))
+(set intervals (map-right + [-1000 1000] (at trades 'Ts)))
 
 (window-join [Sym Ts] intervals trades quotes
     {bid: (min Bid) ask: (max Ask)})
diff --git a/docs/docs/reference/all-functions.md b/docs/docs/reference/all-functions.md
index 6972523a..649b37da 100644
--- a/docs/docs/reference/all-functions.md
+++ b/docs/docs/reference/all-functions.md
@@ -140,8 +140,8 @@ Functions that take other functions as arguments for mapping, folding, and filte
 | `scan-right` | variadic | — | Right-to-left running fold | `(scan-right + (enlist 1 2 3))` → `[6 5 3]` |
 | `filter` | binary | — | Keep elements where boolean mask is true | `(filter [1 2 3 4] (> [1 2 3 4] 2))` → `[3 4]` |
 | `apply` | variadic | — | Zip-apply function pairwise over lists | `(apply + (enlist 1 2) (enlist 3 4))` → `[4 6]` |
-| `map-left` | variadic | — | Map with left argument fixed | `(map-left + 10 [1 2 3])` → `[11 12 13]` |
-| `map-right` | variadic | — | Map with right argument fixed | `(map-right - [10 20 30] 5)` → `[5 15 25]` |
+| `map-left` | variadic | — | Map each element of the left over the whole right | `(map-left + 10 [1 2 3])` → `[11 12 13]` |
+| `map-right` | variadic | — | Map the whole left over each element of the right | `(map-right - [10 20 30] 5)` → `[5 15 25]` |
 
 ```lisp
 ; Transform each row with map
diff --git a/src/lang/eval.c b/src/lang/eval.c
index a0ec8d0c..496143c9 100644
--- a/src/lang/eval.c
+++ b/src/lang/eval.c
@@ -1331,8 +1331,8 @@ ray_t* ray_table_fn(ray_t* names, ray_t* cols) {
             { ray_release(tbl); if (_bxn) ray_release(_bxn); if (_bxc) ray_release(_bxc); return ray_error("domain", NULL); }
 
         /* Empty generic list → typeless empty column: keep it as a RAY_LIST
-         * so its storage type is adopted from the first inserted value
-         * (q-style () column), rather than defaulting to I64. */
+         * so its storage type is adopted from the first inserted value,
+         * rather than defaulting to I64. */
         if (nrows == 0) {
             ray_retain(col_src);
             tbl = ray_table_add_col(tbl, name_id, col_src);
diff --git a/src/ops/collection.c b/src/ops/collection.c
index f9f5410a..381d6fbc 100644
--- a/src/ops/collection.c
+++ b/src/ops/collection.c
@@ -2200,26 +2200,28 @@ static ray_t* map_iterate(ray_t* fn, ray_t* fixed, ray_t* vec, int fixed_is_left
     return out;
 }
 
-/* (map-left fn left right) → fix the LEFT arg, iterate over the right:
- * apply fn(left, right_i) for each element of right. If right is scalar this
- * collapses to a single fn(left, right) (handled by map_iterate). */
+/* (map-left fn left right): iterate the LEFT operand, pairing each element with
+ * the whole RIGHT → fn(left_i, right).
+ * (map-right fn left right): iterate the RIGHT operand, pairing the whole LEFT
+ * with each element → fn(left, right_i).
+ *
+ * The iterated side is fixed by the operator, not auto-detected. When that side
+ * is an atom there is nothing to iterate, so fn is applied once to (left,right);
+ * for an atomic fn that single call is exactly its broadcast over the other
+ * operand, so map-left/map-right agree with plain atomic application there.
+ * Every call goes through call_fn2, which routes atomic builtins through the
+ * broadcasting engine (so a held vector conforms element-wise) and hands
+ * lambdas their arguments whole. */
 ray_t* ray_map_left_fn(ray_t** args, int64_t n) {
     if (n != 3) return ray_error("domain", NULL);
-    ray_t* fn = args[0];
-    ray_t* left = args[1];
-    ray_t* right = args[2];
-    return map_iterate(fn, left, right, 1); /* fn(left, right_i) */
+    /* iterate left (vec), hold right (fixed) → fn(left_i, right) */
+    return map_iterate(args[0], args[2], args[1], 0);
 }
 
-/* (map-right fn left right) → fix the RIGHT arg, iterate over the left:
- * apply fn(left_i, right) for each element of left. If left is scalar this
- * collapses to a single fn(left, right) (handled by map_iterate). */
 ray_t* ray_map_right_fn(ray_t** args, int64_t n) {
     if (n != 3) return ray_error("domain", NULL);
-    ray_t* fn = args[0];
-    ray_t* left = args[1];
-    ray_t* right = args[2];
-    return map_iterate(fn, right, left, 0); /* fn(left_i, right) */
+    /* iterate right (vec), hold left (fixed) → fn(left, right_i) */
+    return map_iterate(args[0], args[1], args[2], 1);
 }
 
 /* ══════════════════════════════════════════
diff --git a/src/ops/query.c b/src/ops/query.c
index b5d67bd2..34525440 100644
--- a/src/ops/query.c
+++ b/src/ops/query.c
@@ -9198,7 +9198,7 @@ ray_t* ray_xbar_fn(ray_t* col, ray_t* bucket) {
  * ══════════════════════════════════════════ */
 
 /* Derive the storage type for a typeless (empty RAY_LIST) column from the
- * first value inserted into it — q-style () columns adopt their type on the
+ * first value inserted into it — an empty () column adopts its type on the
  * first insert. Returns the RAY_* column type, or RAY_LIST when the payload
  * is itself nested (non-atom elements → a genuine list column). */
 static int8_t typeless_col_type(ray_t* payload) {
diff --git a/test/rfl/collection/cov2.rfl b/test/rfl/collection/cov2.rfl
index 9ad6813d..ad5a5f86 100644
--- a/test/rfl/collection/cov2.rfl
+++ b/test/rfl/collection/cov2.rfl
@@ -201,30 +201,43 @@
 (count (binr [1 3 5] [0 2 4])) -- 3
 
 ;; ════════════════════════════════════════════════════════════════
-;; 13. map-left (lines 2108-2121)
+;; 13. map-left: iterate the LEFT, hold the right whole, calling fn(left_i,
+;;     right). An atom on the left iterates once, which for an atomic fn is
+;;     identical to plain broadcast application.
 ;; ════════════════════════════════════════════════════════════════
-;; fn fixed vec: fn(fixed, elem) for each elem
 (map-left + 10 (list 1 2 3)) -- (list 11 12 13)
 (map-left * 3 (list 2 4 6)) -- (list 6 12 18)
 ;; map-left arity error
 (try (map-left + 1) (fn [e] "err")) -- "err"
 
-;; map-left auto-detect: vec is scalar, fixed is vector → swap roles
+;; Iterate the left vector, holding the right scalar.
 (map-left + (list 1 2 3) 5) -- (list 6 7 8)
 (map-left - (list 10 20 30) 5) -- (list 5 15 25)
+;; Non-broadcasting lambda exposes the structure builtins hide. Iterating the
+;; left vector yields one cell per element; an atom left applies fn once.
+(map-left (fn [x y] (list x y)) [1 2 3] 10)    -- (list [1 10] [2 10] [3 10])
+(map-left (fn [x y] (list x y)) 10 [1 2 3])    -- (list 10 [1 2 3])
 
 ;; ════════════════════════════════════════════════════════════════
-;; 14. map-right (lines 2125-2138)
+;; 14. map-right: iterate the RIGHT, hold the left whole, calling fn(left,
+;;     right_i). An atom on the right iterates once, which for an atomic fn is
+;;     identical to plain broadcast application.
 ;; ════════════════════════════════════════════════════════════════
-;; fn vec fixed: fn(elem, fixed) for each elem
 (map-right - (list 10 20 30) 3) -- (list 7 17 27)
 (map-right + (list 1 2 3) 100) -- (list 101 102 103)
 ;; map-right arity error
 (try (map-right + 1) (fn [e] "err")) -- "err"
 
-;; map-right auto-detect: vec is scalar, fixed is vector → iterate fixed
+;; Iterate the right vector, holding the left scalar.
 (map-right + 5 (list 1 2 3)) -- (list 6 7 8)
 (map-right - 100 (list 1 2 3)) -- (list 99 98 97)
+;; Non-broadcasting lambda: iterating the right vector pairs the whole left with
+;; each element (fn order is source order); an atom right applies fn once.
+(map-right (fn [x y] (list x y)) 10 [1 2 3])   -- (list [10 1] [10 2] [10 3])
+(map-right (fn [x y] (list x y)) [1 2 3] 10)   -- (list [1 2 3] 10)
+;; concat is non-broadcasting: iterating the right yields one concat(10,e) per
+;; element ([10 e]); a single concat(10,[1 2 3]) would instead flatten.
+(map-right concat 10 [1 2 3])                  -- (list [10 1] [10 2] [10 3])
 
 ;; ════════════════════════════════════════════════════════════════
 ;; 15. map-iterate scalar path (line 2070-2075):
diff --git a/test/rfl/integration/joins.rfl b/test/rfl/integration/joins.rfl
index 7f03ac91..fbafe89a 100644
--- a/test/rfl/integration/joins.rfl
+++ b/test/rfl/integration/joins.rfl
@@ -74,45 +74,45 @@
 (sum (at ijmk 'val1)) -- 400
 (sum (at ijmk 'val2)) -- 4000
 ;; window-join
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {minBid: (min Bid)}) 'minBid) -- [99 101]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {minBid: (min Bid)}) 'minBid) -- [99 101]
 ;; window-join1
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(at (window-join1 [Sym Time] intervals trades quotes {minBid: (min Bid)}) 'minBid) -- [99 101]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(at (window-join1 [Sym Time] intervals trades quotes {minBid: (min Bid)}) 'minBid) -- [99 101]
 ;; window-join with multiple aggregations — both columns must be present
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid Ask] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101] [110 111 112])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(set r (window-join [Sym Time] intervals trades quotes {lo: (min Bid) hi: (max Ask)}))(at r 'lo) -- [99 101]
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid Ask] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101] [110 111 112])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(set r (window-join [Sym Time] intervals trades quotes {lo: (min Bid) hi: (max Ask)}))(at r 'hi) -- [111 112]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid Ask] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101] [110 111 112])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(set r (window-join [Sym Time] intervals trades quotes {lo: (min Bid) hi: (max Ask)}))(at r 'lo) -- [99 101]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid Ask] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101] [110 111 112])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(set r (window-join [Sym Time] intervals trades quotes {lo: (min Bid) hi: (max Ask)}))(at r 'hi) -- [111 112]
 ;; window-join rayforce1 canonical example (docs/queries-joins.html)
 ;;   trades at 12:00:01, 12:00:04, 12:00:06 ± 1s windows
 ;;   quotes at 12:00:00..12:00:09 sizes [928 528 648 914 918 626 577 817 620 698]
 ;;     trade @ 01 window [00,02] -> sizes [928 528 648], min=528, max=928
 ;;     trade @ 04 window [03,05] -> sizes [914 918 626], min=626, max=918
 ;;     trade @ 06 window [05,07] -> sizes [626 577 817], min=577, max=817
-(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {size_min: (min Size) size_max: (max Size)}) 'size_min) -- [528 626 577]
-(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {size_min: (min Size) size_max: (max Size)}) 'size_max) -- [928 918 817]
+(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {size_min: (min Size) size_max: (max Size)}) 'size_min) -- [528 626 577]
+(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {size_min: (min Size) size_max: (max Size)}) 'size_max) -- [928 918 817]
 ;; window-join sum/count/avg over the same canonical example
 ;;   trade @ 01 window [00,02]: sum=2104 count=3 avg≈701.3333
 ;;   trade @ 04 window [03,05]: sum=2458 count=3 avg≈819.3333
 ;;   trade @ 06 window [05,07]: sum=2020 count=3 avg≈673.3333
-(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {s: (sum Size)}) 's) -- [2104 2458 2020]
-(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {c: (count Size)}) 'c) -- [3 3 3]
+(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {s: (sum Size)}) 's) -- [2104 2458 2020]
+(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {c: (count Size)}) 'c) -- [3 3 3]
 ;; window-join first/last over the canonical example
 ;;   trade @ 01 window [00,02]: first=928 last=648
 ;;   trade @ 04 window [03,05]: first=914 last=626
 ;;   trade @ 06 window [05,07]: first=626 last=817
-(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {f: (first Size)}) 'f) -- [928 914 626]
-(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {l: (last Size)}) 'l) -- [648 626 817]
+(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {f: (first Size)}) 'f) -- [928 914 626]
+(set trades (table [Sym Time Price] (list [x x x] [12:00:01 12:00:04 12:00:06] [89.17 70.5 80.54])))(set quotes (table [Sym Time Size] (list [x x x x x x x x x x] [12:00:00 12:00:01 12:00:02 12:00:03 12:00:04 12:00:05 12:00:06 12:00:07 12:00:08 12:00:09] [928 528 648 914 918 626 577 817 620 698])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {l: (last Size)}) 'l) -- [648 626 817]
 ;; window-join raw bare-column form must accept non-numeric columns (regression)
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Tag] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [foo bar baz])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(count (at (window-join [Sym Time] intervals trades quotes {tags: Tag}) 'tags)) -- 2
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Tag] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [foo bar baz])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(count (at (window-join [Sym Time] intervals trades quotes {tags: Tag}) 'tags)) -- 2
 ;; window-join (count Col) must accept non-numeric source columns.
 ;; trades at 10:00:01 and 10:00:05 with ±1s windows; Tag rows at 10:00:00/02/04:
 ;;   trade @ 01 window [00, 02] -> matches at 00 and 02 (2)
 ;;   trade @ 05 window [04, 06] -> matches at 04 (1)
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Tag] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [foo bar baz])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {n: (count Tag)}) 'n) -- [2 1]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Tag] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [foo bar baz])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {n: (count Tag)}) 'n) -- [2 1]
 ;; window-join COUNT must include window matches whose source value is null
 ;; ((count Col) is COUNT(*) semantics, not COUNT(non-null Col)).
 ;;   trade @ 01 window [00, 02]: Bid rows at 00(99) and 02(NULL) -> count=2, min=99
 ;;   trade @ 05 window [04, 06]: Bid row at 04(101)              -> count=1, min=101
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 0Nl 101])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {c: (count Bid)}) 'c) -- [2 1]
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 0Nl 101])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {m: (min Bid)}) 'm) -- [99 101]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 0Nl 101])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {c: (count Bid)}) 'c) -- [2 1]
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 0Nl 101])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {m: (min Bid)}) 'm) -- [99 101]
 ;; stddev/stddev_pop/var/var_pop must work as standalone aggregation
 ;; builtins so resolve_agg_opcode support in window-join is fully backed
 ;; by an eval-level implementation.
@@ -136,14 +136,14 @@
 ;; if the compare assumed 8-byte stride).
 ;;   AAPL trade @ 01 window [00, 02]: AAPL quotes at 00, 02  -> min=100 max=201
 ;;   MSFT trade @ 01 window [00, 02]: MSFT quotes at 00, 02  -> min=300 max=401
-(set trades (table [Sym Time Price] (list [AAPL MSFT] [10:00:01.000 10:00:01.000] [10 20])))(set quotes (table [Sym Time Bid Ask] (list [AAPL AAPL AAPL MSFT MSFT MSFT] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:00.000 10:00:02.000 10:00:04.000] [100 101 102 300 301 302] [200 201 202 400 401 402])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {lo: (min Bid)}) 'lo) -- [100 300]
-(set trades (table [Sym Time Price] (list [AAPL MSFT] [10:00:01.000 10:00:01.000] [10 20])))(set quotes (table [Sym Time Bid Ask] (list [AAPL AAPL AAPL MSFT MSFT MSFT] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:00.000 10:00:02.000 10:00:04.000] [100 101 102 300 301 302] [200 201 202 400 401 402])))(set intervals (map-left + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {hi: (max Ask)}) 'hi) -- [201 401]
+(set trades (table [Sym Time Price] (list [AAPL MSFT] [10:00:01.000 10:00:01.000] [10 20])))(set quotes (table [Sym Time Bid Ask] (list [AAPL AAPL AAPL MSFT MSFT MSFT] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:00.000 10:00:02.000 10:00:04.000] [100 101 102 300 301 302] [200 201 202 400 401 402])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {lo: (min Bid)}) 'lo) -- [100 300]
+(set trades (table [Sym Time Price] (list [AAPL MSFT] [10:00:01.000 10:00:01.000] [10 20])))(set quotes (table [Sym Time Bid Ask] (list [AAPL AAPL AAPL MSFT MSFT MSFT] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:00.000 10:00:02.000 10:00:04.000] [100 101 102 300 301 302] [200 201 202 400 401 402])))(set intervals (map-right + [-1000 1000] (at trades 'Time)))(at (window-join [Sym Time] intervals trades quotes {hi: (max Ask)}) 'hi) -- [201 401]
 ;; window-join with raw column (TYPE_MAPGROUP)
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(count (at (window-join [Sym Time] intervals trades quotes {bids: Bid}) 'bids)) -- 2
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(count (at (window-join [Sym Time] intervals trades quotes {bids: Bid}) 'bids)) -- 2
 ;; window-join1 with raw column (TYPE_MAPGROUP)
-(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-left + [-2000 2000] (at trades 'Time)))(count (at (window-join1 [Sym Time] intervals trades quotes {bids: Bid}) 'bids)) -- 2
+(set trades (table [Sym Time Price] (list [a a] [10:00:01.000 10:00:05.000] [100 200])))(set quotes (table [Sym Time Bid] (list [a a a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))(set intervals (map-right + [-2000 2000] (at trades 'Time)))(count (at (window-join1 [Sym Time] intervals trades quotes {bids: Bid}) 'bids)) -- 2
 ;; window-join with Enum columns (xasc converts Enum to Symbol)
-(set trades (table [s time price] (list ['a 'a 'b] [10:00:01.000 10:00:05.000 10:00:03.000] [100 200 150])))(set quotes (table [s time bid] (list ['a 'a 'a 'b 'b] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:01.000 10:00:04.000] [99 100 101 149 151])))(set intervals (map-left + [-2000 2000] (at trades 'time)))(at (window-join [s time] intervals trades quotes {minBid: (min bid)}) 'minBid) -- [99 101 149]
+(set trades (table [s time price] (list ['a 'a 'b] [10:00:01.000 10:00:05.000 10:00:03.000] [100 200 150])))(set quotes (table [s time bid] (list ['a 'a 'a 'b 'b] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:01.000 10:00:04.000] [99 100 101 149 151])))(set intervals (map-right + [-2000 2000] (at trades 'time)))(at (window-join [s time] intervals trades quotes {minBid: (min bid)}) 'minBid) -- [99 101 149]
 ;; empty left table
 (set t1 (table [id val1] (list (take [1] 0) (take [1] 0))))(set t2 (table [id val2] (list [1 2 3] [100 200 300])))(count (left-join [id] t1 t2)) -- 0
 ;; empty right table — left-join keeps all 3 left rows with val2 = Null.
diff --git a/test/rfl/io/dump.rfl b/test/rfl/io/dump.rfl
index 8324d8d9..714df328 100644
--- a/test/rfl/io/dump.rfl
+++ b/test/rfl/io/dump.rfl
@@ -85,7 +85,7 @@
 ;; window-join + window-join1 both compile to OP_WINDOW_JOIN.
 (set tr (table [s tm p] (list ['a 'a] [10:00:01.000 10:00:05.000] [100 200])))
 (set qt (table [s tm b] (list ['a 'a 'a] [10:00:00.000 10:00:02.000 10:00:04.000] [99 100 101])))
-(set iv (map-left + [-2000 2000] (at tr 'tm)))
+(set iv (map-right + [-2000 2000] (at tr 'tm)))
 (at (window-join [s tm] iv tr qt {mb: (min b)}) 'mb) -- [99 101]
 (at (window-join1 [s tm] iv tr qt {mb: (min b)}) 'mb) -- [99 101]
 
diff --git a/test/rfl/ops/exec_coverage.rfl b/test/rfl/ops/exec_coverage.rfl
index a3bdea9d..3c95ff24 100644
--- a/test/rfl/ops/exec_coverage.rfl
+++ b/test/rfl/ops/exec_coverage.rfl
@@ -122,7 +122,7 @@
 ;; ====================================================================
 (set tr (table [Sym Time Price] (list ['a 'a 'a 'b] [10:00:01.000 10:00:05.000 10:00:09.000 10:00:01.000] [100 200 300 400])))
 (set qu (table [Sym Time Bid] (list ['a 'a 'a 'b 'b] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:00.000 10:00:02.000] [99 100 101 199 200])))
-(set iv (map-left + [-2000 2000] (at tr 'Time)))
+(set iv (map-right + [-2000 2000] (at tr 'Time)))
 (count (at (window-join [Sym Time] iv tr qu {m: (min Bid)}) 'm)) -- 4
 
 ;; ====================================================================
diff --git a/test/rfl/ops/opt_advanced.rfl b/test/rfl/ops/opt_advanced.rfl
index 1116ff9b..cc5183df 100644
--- a/test/rfl/ops/opt_advanced.rfl
+++ b/test/rfl/ops/opt_advanced.rfl
@@ -295,7 +295,7 @@
 ;; Every TR1 row gets at least one matching TQ1 row in its window.
 (set TR1 (table [Sym Time Price] (list ['a 'a 'b] [10:00:01.000 10:00:05.000 10:00:01.000] [100 200 400])))
 (set TQ1 (table [Sym Time Bid]   (list ['a 'a 'a 'b] [10:00:00.000 10:00:02.000 10:00:04.000 10:00:00.000] [99 100 101 199])))
-(set IV  (map-left + [-2000 2000] (at TR1 'Time)))
+(set IV  (map-right + [-2000 2000] (at TR1 'Time)))
 (count (at (window-join [Sym Time] IV TR1 TQ1 {m: (min Bid)}) 'm)) -- 3
 
 ;; ====================================================================
diff --git a/test/rfl/ops/opt_branch_cov.rfl b/test/rfl/ops/opt_branch_cov.rfl
index 5eba1b19..30ae65d3 100644
--- a/test/rfl/ops/opt_branch_cov.rfl
+++ b/test/rfl/ops/opt_branch_cov.rfl
@@ -378,7 +378,7 @@
 ;; ════════════════════════════════════════════════════════════════════════
 (set TWJ_T (table [Sym Time Price] (list ['a 'a 'b 'b] [10:00:01.000 10:00:05.000 10:00:01.000 10:00:05.000] [100 200 400 500])))
 (set TWJ_Q (table [Sym Time Bid] (list ['a 'a 'b 'b] [10:00:00.000 10:00:04.000 10:00:00.000 10:00:04.000] [99 101 399 501])))
-(set TWJ_IV (map-left + [-2000 2000] (at TWJ_T 'Time)))
+(set TWJ_IV (map-right + [-2000 2000] (at TWJ_T 'Time)))
 (count (at (window-join [Sym Time] TWJ_IV TWJ_T TWJ_Q {m: (min Bid)}) 'm)) -- 4
 
 ;; ════════════════════════════════════════════════════════════════════════
diff --git a/test/rfl/ops/query_coverage.rfl b/test/rfl/ops/query_coverage.rfl
index 48837497..2092b2c7 100644
--- a/test/rfl/ops/query_coverage.rfl
+++ b/test/rfl/ops/query_coverage.rfl
@@ -560,7 +560,7 @@
 
 (set wjl (table [Sym Time] (list ['a 'a] [10:00:01.000 10:00:05.000])))
 (set wjr (table [Sym Time Price] (list ['a 'a 'a] [10:00:00.000 10:00:02.000 10:00:04.000] (as 'F64 [99.5 100.5 101.5]))))
-(set wjiv (map-left + [-2000 2000] (at wjl 'Time)))
+(set wjiv (map-right + [-2000 2000] (at wjl 'Time)))
 ;; F64 sum: row0 interval [09:59:59,10:00:03] → prices 99.5+100.5=200.0
 ;;          row1 interval [10:00:03,10:00:07] → price 101.5 only
 (at (window-join [Sym Time] wjiv wjl wjr {total: (sum Price)}) 'total) -- [200.0 101.5]
@@ -633,7 +633,7 @@
 
 (set wjl2 (table [Sym Time] (list ['a 'a] [10:00:01.000 10:00:05.000])))
 (set wjr2 (table [Sym Time Price] (list ['a 'a 'a] [10:00:00.000 10:00:02.000 10:00:04.000] (as 'F64 [99.5 100.5 101.5]))))
-(set wjiv2 (map-left + [-2000 2000] (at wjl2 'Time)))
+(set wjiv2 (map-right + [-2000 2000] (at wjl2 'Time)))
 (at (window-join [Sym Time] wjiv2 wjl2 wjr2 {f: (first Price)}) 'f) -- [99.5 101.5]
 (at (window-join [Sym Time] wjiv2 wjl2 wjr2 {l: (last Price)}) 'l) -- [100.5 101.5]
 
diff --git a/test/rfl/query/query_branch_cov.rfl b/test/rfl/query/query_branch_cov.rfl
index ad005ece..1e9add05 100644
--- a/test/rfl/query/query_branch_cov.rfl
+++ b/test/rfl/query/query_branch_cov.rfl
@@ -828,7 +828,7 @@
 (set wjR (table [Sym Time Bid] (list ['x 'x 'y 'y] [10:00:00.500 10:00:02.500 10:00:01.500 10:00:02.500] [99.0 101.0 199.0 201.0])))
 ;; intervals = per-left-row [lo hi] time window (in nanoseconds offset
 ;; via map-left + to each left Time).
-(set wjIv (map-left + [-2000 2000] (at wjL 'Time)))
+(set wjIv (map-right + [-2000 2000] (at wjL 'Time)))
 ;; Window [-2000ns, +2000ns] around each left Time:
 ;;   (x, 10:00:01) ∩ window 09:59:59..10:00:03 — x-bids @00.5, @02.5 → {99, 101}
 ;;   (y, 10:00:02) ∩ window 10:00:00..10:00:04 — y-bids @01.5, @02.5 → {199, 201}
diff --git a/test/rfl/query/query_update_coverage.rfl b/test/rfl/query/query_update_coverage.rfl
index aabfaba2..0c82e74e 100644
--- a/test/rfl/query/query_update_coverage.rfl
+++ b/test/rfl/query/query_update_coverage.rfl
@@ -360,7 +360,7 @@
 ;; ────────────────────────────────────────────────────────────────────
 (set wjt_null (table [Sym Time] (list ['a] [10:00:03.000])))
 (set wjq_f64null (table [Sym Time Price] (list ['a 'a 'a 'a] [10:00:00.000 10:00:01.000 10:00:02.000 10:00:04.000] [0Nf 2.0 0Nf 4.0])))
-(set wji_null (map-left + [-3000 3000] (at wjt_null 'Time)))
+(set wji_null (map-right + [-3000 3000] (at wjt_null 'Time)))
 
 ;; F64 null sum (line 10059): nn != NULL → sum skips nulls → 2+4=6
 (at (window-join [Sym Time] wji_null wjt_null wjq_f64null {s: (sum Price)}) 's) -- [6.0]
@@ -433,7 +433,7 @@
 ;; ────────────────────────────────────────────────────────────────────
 (set wjt_i32 (table [Sym Time] (list ['a] [10:00:01.000])))
 (set wjq_i32 (table [Sym Time Price] (list ['a 'a] [10:00:00.000 10:00:02.000] (as 'I32 [10 20]))))
-(set wji_i32 (map-left + [-2000 2000] (at wjt_i32 'Time)))
+(set wji_i32 (map-right + [-2000 2000] (at wjt_i32 'Time)))
 
 ;; I32 result type (lines 10273-10274): first/max on I32 col → I32 output
 ;; Element at [0] of result is I32 atom 10i (first Price = 10i, max Price = 20i)
@@ -447,7 +447,7 @@
 ;; I64 null var/stddev (lines 10140-10141): null in I64 col + var → nn != NULL
 (set wjt_nullv (table [Sym Time] (list ['a] [10:00:03.000])))
 (set wjq_i64nv (table [Sym Time Price] (list ['a 'a 'a 'a] [10:00:00.000 10:00:01.000 10:00:02.000 10:00:04.000] [0Nl 2 0Nl 4])))
-(set wji_nullv (map-left + [-3000 3000] (at wjt_nullv 'Time)))
+(set wji_nullv (map-right + [-3000 3000] (at wjt_nullv 'Time)))
 ;; var of non-null [2, 4] = 2.0 (sample variance)
 (at (window-join [Sym Time] wji_nullv wjt_nullv wjq_i64nv {v: (var Price)}) 'v) -- [2.0]
 ;; stddev of non-null [2, 4] = sqrt(2.0) ≈ 1.41
diff --git a/test/rfl/table/update.rfl b/test/rfl/table/update.rfl
index 88dfff66..d8264c6d 100644
--- a/test/rfl/table/update.rfl
+++ b/test/rfl/table/update.rfl
@@ -173,7 +173,7 @@ t -- (table [ID Name Value] (list [1 2] [alice bob] [10.0 20.0]))
 (insert (table [a] (list (as 'Date (list)))) (list 1)) !- type
 
 ;; Typeless empty () column: adopts the type of the first inserted value
-;; (q-style () column) instead of defaulting to I64 and rejecting non-ints.
+;; instead of defaulting to I64 and rejecting non-ints.
 (insert (table [a] (list (list))) (list 3.14)) -- (table [a] (list [3.14]))
 (insert (table [a] (list (list))) (list 'x)) -- (table [a] (list ['x]))
 (insert (table [a] (list (list))) (list "s")) -- (table [a] (list (list "s")))