Tramaj.Halogen

foldToHalogen :: forall action slots m. (String -> String -> Json -> Maybe action) -> Node -> Array (ComponentHTML action slots m)

dispatch maps an action — its event type, its key, and its JSON payload — onto a real Halogen action; a host that wants purely read-only rendering supplies \_ _ _ -> Nothing. An action that maps to Nothing attaches no handler at all.

Every action dispatch accepts is wired to HE.onClick, without this module looking at the event type: evaluation does not restrict that string to any vocabulary, so dispatch is the only place that can tell "on-click" from anything else and must return Nothing for event types it does not want turned into a click. Continuous-input handling is out of scope.

Returns an Array because a Tramaj.Node need not be a single element: a fragment contributes its children with no wrapper, which is the whole point of it. A host rendering a document root splices the result into whatever container it already has.

foldToHalogen trusts that attribute names are legal DOM attribute names and passes them to HP.attr. The language does not restrict them, so a template can produce a name the DOM rejects, throwing mid-render. Call validateAttrNames first and handle a non-empty result rather than folding straight through.

An svg element and its descendants are built in the SVG namespace so they actually paint (see foldIn).

renderScalar :: Json -> String

How this host renders a JSON value as DOM text. A symbol (v3-symbols §5.3's {"$sym": ..., "path": [...]} tag) renders as its id with its path dotted on, e.g. #0:"d".replicas. Otherwise: a string is itself, a whole number drops its trailing .0, null renders as nothing, and anything structured falls back to compact JSON.

Deliberately this module's decision rather than the evaluator's: a different host targeting YAML or a UI model would render the same values differently, and v2's Node keeps them unconverted precisely so that it can.

isValidAttrName :: String -> Boolean

A DOM attribute name this module is willing to set: alphanumeric plus -/_ only (no spaces, colons, quotes) — deliberately stricter than HTML itself permits, since the only names templates should need are kebab-case/snake_case identifiers like data-count.

validateAttrNames :: Node -> Array String

Every invalid attribute name found anywhere in the tree (deduplicated, tree order), or [] if node is safe to fold with foldToHalogen.

renderSymbolTable :: forall action slots m. Array Json -> ComponentHTML action slots m

Renders a v3-symbols §5.2 "symbols" array (the envelope's symbol table) as an HTML table: id, origin (an allocation's site and key, or a demand's path), and the binding it was read into, if any. An entry that doesn't match the expected shape renders as a "?" row rather than being dropped or throwing — this is reading a JSON contract, not typed data.

renderConstraintTable :: forall action slots m. Array Json -> ComponentHTML action slots m

Renders a v3-symbols §5.2 "constraints" array as an HTML table: name and arguments, each argument shown with renderScalar — so a symbol argument renders the same placeholder text renderSymbolTable's rows and the document tree use.

renderTypesTable :: forall action slots m. Array Json -> ComponentHTML action slots m

Renders a v4-types \S8 "types" array (the envelope's type table) as an HTML table: canonical id, and its definition rendered to short text by resolvedTypeText. Declaration boundaries stay boundaries here too — a ref definition shows only the id it points at, never the pointee's own definition inlined, since that entry is its own row.

renderTypeConstraintTable :: forall action slots m. Array Json -> ComponentHTML action slots m

Renders a v4-types \S8 "type-constraints" array — same shape as renderConstraintTable's "constraints" (name/arguments), except a type argument is the erased {"$type": ...} tag \S7 reserves rather than a plain scalar, so it needs its own argument formatter.

renderCard :: forall action slots m. Card -> ComponentHTML action slots m

Renders a Tramaj.Analysis.Card — the same five-field summary tramaj-cli analyze card prints as JSON — as a definition list: what the program produces, what its own $ctx must supply, every library it reaches, every action key it can emit, and which import sites still leave one of their library's own parameters unsupplied.

Unlike the symbol/constraint/type tables above, this doesn't decode a JSON envelope — a host that already has the Program and the LibraryTable (as the playground does, from its own tabs) calls Tramaj.Analysis.Card.programCard directly and hands the typed result here.