fixes #9462; jsondoc --index can generate a theindex.json (#20205)

compiler/docgen.nim

@@ -1124,6 +1124,8 @@ proc genJsonItem(d: PDoc, n, nameNode: PNode, k: TSymKind): JsonItem =
         for kind in genericParam.sym.typ.sons:
           param["types"].add %($kind)
         result.json["signature"]["genericParams"].add param
+  if optGenIndex in d.conf.globalOptions:
+    genItem(d, n, nameNode, k, kForceExport)
 
 proc setDoctype(d: PDoc, n: PNode) =
   ## Processes `{.doctype.}` pragma changing Markdown/RST parsing options.
@@ -1782,3 +1784,17 @@ proc commandBuildIndex*(conf: ConfigRef, dir: string, outFile = RelativeFile"")
     writeFile(filename, code)
   except:
     rawMessage(conf, errCannotOpenFile, filename.string)
+
+proc commandBuildIndexJson*(conf: ConfigRef, dir: string, outFile = RelativeFile"") =
+  var (modules, symbols, docs) = readIndexDir(dir)
+  let documents = toSeq(keys(Table[IndexEntry, seq[IndexEntry]](docs)))
+  let body = %*({"documents": documents, "modules": modules, "symbols": symbols})
+
+  var outFile = outFile
+  if outFile.isEmpty: outFile = theindexFname.RelativeFile.changeFileExt("")
+  let filename = getOutFile(conf, outFile, JsonExt)
+
+  try:
+    writeFile(filename, $body)
+  except:
+    rawMessage(conf, errCannotOpenFile, filename.string)

compiler/main.nim

@@ -325,7 +325,11 @@ proc mainCommand*(graph: ModuleGraph) =
       else:
         docLikeCmd commandDoc2(graph, TexExt)
   of cmdJsondoc0: docLikeCmd commandJson(cache, conf)
-  of cmdJsondoc: docLikeCmd commandDoc2(graph, JsonExt)
+  of cmdJsondoc:
+    docLikeCmd():
+      commandDoc2(graph, JsonExt)
+      if optGenIndex in conf.globalOptions and optWholeProject in conf.globalOptions:
+        commandBuildIndexJson(conf, $conf.outDir)
   of cmdCtags: docLikeCmd commandTags(cache, conf)
   of cmdBuildindex: docLikeCmd commandBuildIndex(conf, $conf.projectFull, conf.outFile)
   of cmdGendepend: commandGenDepend(graph)

lib/packages/docutils/rstgen.nim

@@ -417,13 +417,13 @@ proc renderIndexTerm*(d: PDoc, n: PRstNode, result: var string) =
         [id, term])
 
 type
-  IndexEntry = object
-    keyword: string
-    link: string
-    linkTitle: string ## contains a prettier text for the href
-    linkDesc: string ## the title attribute of the final href
+  IndexEntry* = object
+    keyword*: string
+    link*: string
+    linkTitle*: string ## contains a prettier text for the href
+    linkDesc*: string ## the title attribute of the final href
 
-  IndexedDocs = Table[IndexEntry, seq[IndexEntry]] ## \
+  IndexedDocs* = Table[IndexEntry, seq[IndexEntry]] ## \
     ## Contains the index sequences for doc types.
     ##
     ## The key is a *fake* IndexEntry which will contain the title of the
@@ -625,7 +625,7 @@ proc generateModuleJumps(modules: seq[string]): string =
 
   result.add(chunks.join(", ") & ".<br/>")
 
-proc readIndexDir(dir: string):
+proc readIndexDir*(dir: string):
     tuple[modules: seq[string], symbols: seq[IndexEntry], docs: IndexedDocs] =
   ## Walks `dir` reading ``.idx`` files converting them in IndexEntry items.
   ##
@@ -691,8 +691,6 @@ proc readIndexDir(dir: string):
         title.linkTitle = "doc_toc_" & $result.docs.len
         result.docs[title] = fileEntries
 
-  sort(result.modules, system.cmp)
-
 proc mergeIndexes*(dir: string): string =
   ## Merges all index files in `dir` and returns the generated index as HTML.
   ##
@@ -722,6 +720,7 @@ proc mergeIndexes*(dir: string): string =
   ## Returns the merged and sorted indices into a single HTML block which can
   ## be further embedded into nimdoc templates.
   var (modules, symbols, docs) = readIndexDir(dir)
+  sort(modules, system.cmp)
 
   result = ""
   # Generate a quick jump list of documents.