Answer architecture round 2: refuse a self-read only inside what the binding lands on, fix the struct.go Layout line, move loneRef beside its caller, and widen item 83 to the link passes

README.md

@@ -959,7 +959,7 @@ scope.go        the scope a render reads names and rows through
 path.go         the dotted-path walks with their selectors, and proving a path resolves
 render.go       Fake, the recursive renderer (choices, format strings, expansions) and the reads its tokens make
 record.go       records: Record, the JSON/CSV/SQL serializers, and their entry points
-struct.go       structs: FakeStruct, fake tags, the one pick a struct's path tags into one category read, and a field's Go type as its column's datatype
+struct.go       structs: FakeStruct, fake tags as one record's columns, and a field's Go type as its column's datatype
 inline.go       inline templates: Template, NewTemplate, FakeTemplate, IsTemplate, and their compile and link
 format.go       the {token} grammar: scanning, tokens, operands, validation, compiling a format
 pins.go         the pin set: the table rows one path or one named pick fixes

inline.go

@@ -206,3 +206,11 @@ func linkNodeRefs(scope nodeScope, root map[string]node) error {
 	}
 	return nil
 }
+
+// loneRef is the reference a format of one reference token and nothing else reads.
+func loneRef(toks []formatToken) (string, bool) {
+	if len(toks) != 1 || toks[0].kind != nameRead || len(toks[0].names) != 1 || !isRef(toks[0].names[0]) {
+		return "", false
+	}
+	return toks[0].names[0], true
+}

name_test.go

@@ -417,3 +417,9 @@ func TestANameReadAloneIsTheRecordColumnItReads(t *testing.T) {
 		t.Errorf("NewRecordTemplate = %v, want a name-read column accepted inline", err)
 	}
 }
+
+func TestAFieldBindingReadOutsideWhatItBindsLoads(t *testing.T) {
+	if _, err := engine(1).NewTemplate(`{"format":"{x.y as n}{n}{n}{x}","x":{"format":"{z}","y":["a","b"],"z":"{n}"}}`); err != nil {
+		t.Errorf("NewTemplate = %v, want a read of n from x.z, outside x.y, accepted", err)
+	}
+}

namefence.go

@@ -1,7 +1,6 @@
 package fejkdata
 
 import (
-	"errors"
 	"fmt"
 	"slices"
 	"strings"
@@ -19,7 +18,7 @@ func checkNameReads(path string, t *template) error {
 		}
 	}
 	return namedReads(t, func(o *op, a *arm) error {
-		if a.named.bindsField() && rendersInside(a.named.head, t) {
+		if a.named.bindsField() && rendersInside(compilePath(a.named.head, a.named.tail).leaves, t) {
 			return fmt.Errorf("%s: token {%s}: name %q is read inside %q, the field it binds, which would render itself; read the name outside that field", t.site.label(path), o.body, a.named.name, a.named.ref)
 		}
 		for _, leaf := range a.leaves {
@@ -31,18 +30,33 @@ func checkNameReads(path string, t *template) error {
 	})
 }
 
-// rendersInside reports whether t sits in what n contains.
-func rendersInside(n node, t *template) bool {
-	return eachNode(n, "", func(_ string, m node) error {
-		if m == t {
-			return errFound
+// rendersInside reports whether t sits in what one of nodes contains.
+func rendersInside(nodes []node, t *template) bool {
+	seen := map[node]bool{}
+	var inside func(n node) bool
+	inside = func(n node) bool {
+		if n == node(t) {
+			return true
 		}
-		return nil
-	}) != nil
+		if seen[n] {
+			return false
+		}
+		seen[n] = true
+		for _, c := range contained(n) {
+			if inside(c.node) {
+				return true
+			}
+		}
+		return false
+	}
+	for _, n := range nodes {
+		if inside(n) {
+			return true
+		}
+	}
+	return false
 }
 
-var errFound = errors.New("found")
-
 // checkUses refuses a binding read once at a spot the bound spelling can stand: that spelling
 // draws the same way without the name. A field stands only beside its binding.
 func (b *nameBinding) checkUses() error {

reference.go

@@ -251,11 +251,3 @@ func refTokens(toks []formatToken) []string {
 	}
 	return refs
 }
-
-// loneRef is the reference a format of one reference token and nothing else reads.
-func loneRef(toks []formatToken) (string, bool) {
-	if len(toks) != 1 || toks[0].kind != nameRead || len(toks[0].names) != 1 || !isRef(toks[0].names[0]) {
-		return "", false
-	}
-	return toks[0].names[0], true
-}

todo.md

@@ -131,7 +131,7 @@
 | 95 | 0.3.0 | principle | **Hold a struct's columns and the field each fills in one slice.** | 1 | 2 | 1 | 5 | 3.2 | 9.5 |
 | 19 | 0.3.0 |  | **Fill the 398 Swedish localities weighted 200 from SCB småorter.** | 2 | 4 | 4 | 6 | 14.1 | 9.2 |
 | 56 | 0.3.0 | defect | **Build on a manual run of `test.yml`.** | 1 | 1 | 1 | 4 | 1 | 8.8 |
-| 83 | 0.3.0 | principle | **Read a name binding's head and tail from its binder's link, and delete `linkBindings`.** | 4 | 3 | 1 | 6 | 3.2 | 8.1 |
+| 83 | 0.3.0 | principle | **Read a name binding's head and tail from its binder's link, and have each link pass return what it compiles, so `linkBindings` goes and no pass reads what an earlier one wrote in place.** | 4 | 4 | 1 | 6 | 3.2 | 7.8 |
 | 63 | 0.4.0 |  | **Pair a street with its exact postnummer.** | 3 | 6 | 5 | 8 | 4.1 | 19.1 |
 | 62 | 0.4.0 |  | **Add `{btc()}` and `{eth()}`.** | 2 | 4 | 4 | 6 | 4 | 15.2 |
 | 59 | 0.4.0 |  | **Promise in `Generator`'s godoc that its renders run one at a time.** | 1 | 1 | 5 | 5 | 12 | 13.2 |
@@ -446,9 +446,9 @@ Its doc says render failure, and it wraps what `NewTemplate` and `NewRecordTempl
 
 `workflow_dispatch` leaves `github.event.before` empty, so the diff compares `HEAD` with itself and skips `docker build`.
 
-### 83. Read a name binding's head and tail from its binder's link, and delete `linkBindings`.
+### 83. Read a name binding's head and tail from its binder's link, and have each link pass return what it compiles, so `linkBindings` goes and no pass reads what an earlier one wrote in place.
 
-`linkBindings` writes `nameBinding.head` and `tail` in `linkRefs`'s first pass and `linkName` reads them in its second, so swapping the passes hands `linkName` a nil head. Technical principle: one owner per value.
+`linkBindings` writes `nameBinding.head` and `tail` in `linkRefs`'s first pass and `linkName` reads them in its second, so swapping the passes hands `linkName` a nil head. `linkPasses` does the same: `linkColumnRead` reads the `arm.named` that `linkNames` wrote, and `checkNameReads` the arms both filled. Technical principle: one owner per value.
 
 ### 63. Pair a street with its exact postnummer.