nimsuggest: move library code into suggest (#892)

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## Summary

Extract procedures that do not rely on the command-line from the
`nimsuggest` module to the `suggest` module.

## Details

Changes:

- procedure `findNode` was moved and renamed to `findTrackedNode`
- procedure `symFromInfo` was moved and renamed to `findTrackedSym`
- the ide command execution part of `executeNoHooks` was extracted and
  moved into `executeCmd`

This makes the `suggest` module more of a reusable component for other
non-`nimsuggest` tools, e.g. the LSP server.

---------

Co-authored-by: Saem Ghani <saemghani+github@gmail.com>

compiler/tools/suggest.nim

@@ -55,6 +55,7 @@ import
     options,
   ],
   compiler/modules/[
+    modules,
     modulegraphs,
   ],
   compiler/sem/[
@@ -65,7 +66,8 @@ import
   compiler/utils/[
     prefixmatches,
     astrepr,
-    debugutils
+    debugutils,
+    pathutils
   ]
 
 
@@ -464,6 +466,52 @@ proc isTracked*(current, trackPos: TLineInfo, tokenLen: int): bool =
     if col >= current.col and col <= current.col + tokenLen - 1:
       return true
 
+proc findTrackedNode(n: PNode; trackPos: TLineInfo): PSym =
+  if n.kind == nkSym:
+    if isTracked(n.info, trackPos, n.sym.name.s.len): return n.sym
+  else:
+    for i in 0 ..< safeLen(n):
+      let res = findTrackedNode(n[i], trackPos)
+      if res != nil: return res
+
+proc findTrackedSym*(g: ModuleGraph;): PSym =
+  let m = g.getModule(g.config.m.trackPos.fileIndex)
+  if m != nil and m.ast != nil:
+    # xxx: the node finding should be specialized per symbol kind
+    result = findTrackedNode(m.ast, g.config.m.trackPos)
+
+proc executeCmd*(cmd: IdeCmd, file, dirtyfile: AbsoluteFile, line, col: int;
+             graph: ModuleGraph) =
+  ## executes the given suggest command, `cmd`, for a given `file`, at the
+  ## position described by `line` and `col`umn. If `dirtyFile` is non-empty,
+  ## then its contents are used as part of the analysis.
+  let conf = graph.config
+  conf.ideCmd = cmd
+  var isKnownFile = true
+  let dirtyIdx = fileInfoIdx(conf, file, isKnownFile)
+
+  if dirtyfile.isEmpty: msgs.setDirtyFile(conf, dirtyIdx, AbsoluteFile"")
+  else: msgs.setDirtyFile(conf, dirtyIdx, dirtyfile)
+
+  conf.m.trackPos = newLineInfo(dirtyIdx, line, col)
+  conf.m.trackPosAttached = false
+  conf.errorCounter = 0
+  if not isKnownFile:
+    graph.compileProject(dirtyIdx)
+  if conf.ideCmd in {ideUse, ideDus} and
+      dirtyfile.isEmpty:
+    discard "no need to recompile anything"
+  else:
+    let modIdx = graph.parentModule(dirtyIdx)
+    graph.markDirty dirtyIdx
+    graph.markClientsDirty dirtyIdx
+    # partially recompiling the project means that that VM and JIT state
+    # would become stale, which we prevent by discarding all of it:
+    graph.vm = nil
+    if conf.ideCmd != ideMod:
+      if isKnownFile:
+        graph.compileProject(modIdx)
+
 when defined(nimsuggest):
 
   proc addNoDup(s: PSym; info: TLineInfo) =

nimsuggest/nimsuggest.nim

@@ -57,7 +57,7 @@ from compiler/ast/reports import Report,
 
 from compiler/front/main import customizeForBackend
 
-from compiler/tools/suggest import isTracked, listUsages, suggestSym, `$`
+from compiler/tools/suggest import findTrackedSym, executeCmd, listUsages, suggestSym, `$`
 
 when defined(windows):
   import winlean
@@ -206,20 +206,6 @@ proc listEpc(): SexpNode =
     methodDesc.add(docstring)
     result.add(methodDesc)
 
-proc findNode(n: PNode; trackPos: TLineInfo): PSym =
-  #echo "checking node ", n.info
-  if n.kind == nkSym:
-    if isTracked(n.info, trackPos, n.sym.name.s.len): return n.sym
-  else:
-    for i in 0 ..< safeLen(n):
-      let res = findNode(n[i], trackPos)
-      if res != nil: return res
-
-proc symFromInfo(graph: ModuleGraph; trackPos: TLineInfo): PSym =
-  let m = graph.getModule(trackPos.fileIndex)
-  if m != nil and m.ast != nil:
-    result = findNode(m.ast, trackPos)
-
 proc executeNoHooks(cmd: IdeCmd, file, dirtyfile: AbsoluteFile, line, col: int;
              graph: ModuleGraph) =
   let conf = graph.config
@@ -229,33 +215,9 @@ proc executeNoHooks(cmd: IdeCmd, file, dirtyfile: AbsoluteFile, line, col: int;
       dirtyfile.string & "[" & $line & ":" & $col & "]"
   )
 
-  conf.ideCmd = cmd
-  var isKnownFile = true
-  let dirtyIdx = fileInfoIdx(conf, file, isKnownFile)
-
-  if not dirtyfile.isEmpty: msgs.setDirtyFile(conf, dirtyIdx, dirtyfile)
-  else: msgs.setDirtyFile(conf, dirtyIdx, AbsoluteFile"")
-
-  conf.m.trackPos = newLineInfo(dirtyIdx, line, col)
-  conf.m.trackPosAttached = false
-  conf.errorCounter = 0
-  if not isKnownFile:
-    graph.compileProject(dirtyIdx)
-  if conf.ideCmd in {ideUse, ideDus} and
-      dirtyfile.isEmpty:
-    discard "no need to recompile anything"
-  else:
-    let modIdx = graph.parentModule(dirtyIdx)
-    graph.markDirty dirtyIdx
-    graph.markClientsDirty dirtyIdx
-    # partially recompiling the project means that that VM and JIT state
-    # would become stale, which we prevent by discarding all of it:
-    graph.vm = nil
-    if conf.ideCmd != ideMod:
-      if isKnownFile:
-        graph.compileProject(modIdx)
+  executeCmd(cmd, file, dirtyfile, line, col, graph)
   if conf.ideCmd in {ideUse, ideDus}:
-    let u = graph.symFromInfo(conf.m.trackPos)
+    let u = graph.findTrackedSym()
     if u != nil:
       listUsages(graph, u)
     else: