Answer product-owner round 2: render a record column a name binds whole from the pick

README.md

@@ -137,8 +137,8 @@ it as nothing.
 A record is one render, so its columns read one pick of each [name](#names) its category
 binds: `"code": "{/currency as c}{c.code}"` beside `"symbol": "{c.symbol}"` is one
 currency, while `{/currency.code}` and `{/currency.symbol}` in two columns may name two. A
-field a name binds draws afresh as a column of its own, so write the column through the name,
-`"where": "{p}"` beside `{place as p}`, for it to agree with the columns reading `p`.
+field the format binds whole, `{place as p}`, is a column holding that pick, so it agrees with
+the columns reading `p`.
 
 A category never references itself: `{/users.first}` or a bare `{/users}` inside `users`
 describes a draw other than the fields beside it. Read a sibling as a field, and put a

pick_test.go

@@ -285,3 +285,25 @@ func TestASubFieldIsReachableByFake(t *testing.T) {
 		}
 	}
 }
+
+func TestAFieldBoundWholeIsItsPickAsAColumn(t *testing.T) {
+	f := newGenerator(t, writeData(t, map[string]string{
+		"row": `{"format":"{place as p}{p.locality}","place":[{"format":"{locality}","locality":"Stockholm","zip":"1"},{"format":"{locality}","locality":"Tranås","zip":"5"}],"zip":"{p.zip}"}`,
+	}), WithSeed(1))
+	zips := map[string]string{"Stockholm": "1", "Tranås": "5"}
+	seen := map[string]bool{}
+	for i := 0; i < 100; i++ {
+		r, err := f.FakeRecord("row")
+		if err != nil {
+			t.Fatal(err)
+		}
+		c := r.Columns()
+		if zips[c[0].Value] != c[1].Value {
+			t.Fatalf("%s: want the place column and the zip read through p one place", r.JSON())
+		}
+		seen[c[0].Value] = true
+	}
+	if len(seen) != 2 {
+		t.Errorf("place drew only %v in 100 records, want both", seen)
+	}
+}

record.go

@@ -266,8 +266,28 @@ func renderRecord(s *generatorState, t *template, columns []Column, sc renderSco
 	}
 	r := &Record{columns: append([]Column(nil), columns...)}
 	for i := range r.columns {
-		column := renderLeaf(s, t.fields[r.columns[i].Name], sc)
+		field := t.fields[r.columns[i].Name]
+		var column readValue
+		if b := bindingOfWhole(t, field); b != nil {
+			column = readName(s, sc, arm{kind: namedRead, named: b, levels: []string{""}})
+		} else {
+			column = renderLeaf(s, field, sc)
+		}
 		r.columns[i].Value, r.columns[i].Null = column.text, column.null
 	}
 	return r
 }
+
+// bindingOfWhole is the name t binds to the whole of field, whose pick the field's column renders
+// so the row agrees with the columns reading the name; nil where none does.
+func bindingOfWhole(t *template, field node) *nameBinding {
+	if t.ownNameScope == nil {
+		return nil
+	}
+	for _, b := range t.ownNameScope.order {
+		if b.bindsField() && b.binder == t && len(b.tail) == 0 && b.head == field {
+			return b
+		}
+	}
+	return nil
+}