Yarn Spinner

Export → Yarn Spinner writes one .yarn file for the whole project in Yarn Spinner 2/3 syntax. Drop it into any Yarn Spinner host — Unity, Godot, Unreal, a web runner — and start at the Setup node.

example-scenario.yarn is the example project after export; it is reproduced below.

The mapping

ChatMapper	Yarn
Project	One `.yarn` file. A header comment maps every Yarn title back to its conversation and node.
Project script + variables	A generated `Setup` node: `<<declare>>` for every variable (from `Initial Value`), the translated project script, then a jump to the first conversation’s root. This is the entry point.
Playable node (root included)	One Yarn node, titled `<Conversation>_<NodeTitle>` (sanitised to letters, digits and `_`; suffixed `_2`, `_3` on collision).
Group node	No Yarn node. A group is expanded at every site that links to it, and its condition and script are folded into each child it contributes.
`Dialogue Text`	`Speaker: line` — one Yarn line per `\|` segment. `[var=Name]` becomes `{$Name}`.
One successor	`<<jump Title>>`
Several successors	`->` shortcut options, one per successor, each with its `<<jump>>`. Labelled by `Menu Text` (`[f]`/`[a]` stripped).
A lone `[f]` successor	A one-entry option menu, as the Desktop app would show.
Cross-conversation link	A plain `<<jump>>` — the file is one namespace.
`ConditionsString`	`<<if …>>` around the jump/option, when translatable.
`UserScript`	`<<set …>>` statements at the top of the node’s body, when translatable.
Actor `Name`	The `Speaker:` prefix.

Every multi-successor set becomes options, because ChatMapper offers any multi-successor set as choices — the exporter does not guess from the presence of Menu Text.

What the Lua translation covers

Only exact translations are emitted:

Lua	Yarn
`Variable["x"]`	`$x`
`==` `~=` `<` `<=` `>` `>=`	`==` `!=` `<` `<=` `>` `>=`
`and` `or` `not`	`and` `or` `not`
numbers, strings, `true`, `false`	the same
`Variable["x"] = <expr>`	`<<set $x = <expr>>>`

Anything else — Dialog[n].SimStatus, Actor[…] reads, function calls, nil, string concatenation — is not translated. In that case:

the statement is emitted as a // UNTRANSLATED: … comment exactly where it was, so the human finishing the port sees it in context, and
the export’s warnings list it with the node it came from, so the writer gets a punch list.

A condition that cannot be translated has its gate removed (the jump is unconditional) and is reported the same way — the content stays reachable rather than silently vanishing.

Variables referenced but never declared in the project are declared as 0 with a warning, so the file compiles.

Names

Yarn titles and variable names must start with a letter and contain only word characters. Everything else collapses to _; a name that would start with a digit gets an N_ prefix. The header comment is the map back.

The example, exported

// Yarn Spinner export from ChatMapper.
// Project: The Ferry at Dusk
// Entry point: Setup
//
// Node title map — Yarn title <= conversation / node it came from:
//   Asking_for_passage_Start <= conversation 1 "Asking for passage" / node 0 "START"
//   Asking_for_passage_Opening_line <= conversation 1 "Asking for passage" / node 1 "Opening line"
//   Asking_for_passage_Accept_the_token <= conversation 1 "Asking for passage" / node 3 "Accept the token"
//   Asking_for_passage_Stay_ashore <= conversation 1 "Asking for passage" / node 4 "Stay ashore"
//   Asking_for_passage_Ending_crossing <= conversation 1 "Asking for passage" / node 5 "Ending - crossing"
//   Asking_for_passage_Ending_ashore <= conversation 1 "Asking for passage" / node 6 "Ending - ashore"

title: Setup
---
<<declare $has_token = false>>
<<set $has_token = false>>
<<jump Asking_for_passage_Start>>
===

title: Asking_for_passage_Start
---
<<jump Asking_for_passage_Opening_line>>
===

title: Asking_for_passage_Opening_line
---
Ferryman: Last crossing of the day.
Ferryman: Coming aboard, or staying with the rain?
-> I'll take the crossing.
    <<jump Asking_for_passage_Accept_the_token>>
-> I'll wait for morning.
    <<jump Asking_for_passage_Stay_ashore>>
===

title: Asking_for_passage_Accept_the_token
---
<<set $has_token = true>>
Traveller: I'll take the crossing.
<<if $has_token == true>>
<<jump Asking_for_passage_Ending_crossing>>
<<endif>>
===

title: Asking_for_passage_Stay_ashore
---
Traveller: I'll wait for morning.
<<jump Asking_for_passage_Ending_ashore>>
===

title: Asking_for_passage_Ending_crossing
---
Ferryman: Mind the step. She rolls once we clear the piling.
===

title: Asking_for_passage_Ending_ashore
---
Ferryman: Suit yourself. The rain is not in a hurry either.
===

Note how the group node Traveller’s options has no Yarn node: its two children appear directly as options under Opening line.

What does not carry

Media fields (Audio Files, Pictures…) and custom fields are not part of Yarn’s model. Ship them separately — the JSON export alongside the Yarn, or a CMPKG — keyed by the node IDs in the header map.
SimStatus has no Yarn equivalent; Yarn’s visited() function is the nearest idea, and a script that needs it is reported for manual translation.
Priority and Passthrough have no Yarn equivalent. Successors are emitted in link order with their conditions; a design that relies on priority suppression or passthrough should be checked in the Yarn host.
Emphasis tags are plain text to Yarn. They pass through inside the line; strip or style them in your line view.

Round trip

There is no Yarn importer. Treat the .yarn as a build artifact: edit in ChatMapper, re-export.