DFTE/docs/TEMPLATE_LANGUAGE.md

Template language and lifecycle

Every token has the form %NAME%. DFTE resolves it from a PlaceholderRegistry according to its registered type.

Registered type	Purpose
registerProgmemData()	Static flash-resident text
registerRamData()	Getter returning current const char* data
registerProgmemTemplate()	Nested PROGMEM template
registerDynamicTemplate()	Template fragment supplied at render time
registerConditional()	Choose a true, false, or skipped delegate
registerIterator()	Stream repeated item templates through an iterator handle

Context lifecycle

1. Populate a registry during setup.
2. Attach it to a TemplateContext.
3. Initialise the context with the root placeholder.
4. Call renderNextChunk() until complete or error.
5. Call reset() before reusing a completed context for another root.

Do not treat isComplete() as a success result by itself; check hasError() as well.

Iterators

An iterator opens a handle, produces IteratorItemView values, then closes the handle. Handles are closed when rendering finishes, resets, stalls, or fails. The open, next, and close callbacks must therefore tolerate early termination.

Use AsyncDashboardDemo for a complete iterator example. Use NestedLayouts for partials and conditions.

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