[delchev]

Cause

A .print <table source="items"> / <for> had no way to print the row's ordinal: the DataBinder row scope exposed only the row's own fields (plus the enclosing context), so the "№" column a standard invoice items table starts with was not expressible.

Change

A reserved row variable, {{__index}} (double underscore like __label, the other name the binder reserves):

<table source="items">
    <column width="24" label="№">{{__index}}</column>
    <column width="4*" label="Item">{{Name}}</column>
    <column width="*" label="Amount" align="right">{{Amount}}</column>
</table>

• 1-based, counting the rows actually rendered: numbered after the row filter (filter / match), so a filtered table numbers the kept rows 1, 2, 3 with no gaps.
• With groupBy it is the ordinal of the group (in the order the groups render).
• A number like any other: takes a format ({{__index:00}}), composes with text.
• Nested loops read the innermost row; every table/for counts from 1 again. Outside a row it renders empty.
• The name is reserved: a row (or document) field called __index is not reachable.

Implementation is confined to DataBinder: the row Scope carries its ordinal, assigned in rowScopes after filtering and grouping, and Scope.resolveOwn answers __index from it.

Docs: modules/parsers/document/README.md (next to groupBy), DataBinder class javadoc, .claude/docs/document-templates.md.

Verification

Run locally in a worktree:

• mvn test -pl modules/parsers/document,components/engine/engine-document - parsers-document 155 tests, engine-document 82 tests, 0 failures. New: five DataBinderTest cases (table 1..n; filtered table and for numbered contiguously; group ordinal; nested loops / restart per loop / <if> inside a row; format, reserved over a row field, empty outside a row) and XslFoRendererTest.rendersTheRowOrdinalColumnOfAnItemsTable (the acceptance template down to the XSL-FO cells).
• mvn -T 1C formatter:validate with the formatter cache wiped - green.
• mvn -P release ... install -pl modules/parsers/document (javadoc) - green.

Not verified: no integration test was run locally; no generator or template changed, so no sample-intent-* fixture is affected.

Fixes #8610

🤖 Generated with Claude Code