impr(tonim): no list init-ed for unpack an array; tonim runs alone now

src/pylib/pysugar/stmt/exprRewrite.nim

@@ -81,6 +81,11 @@ template asisIfEmpty(e) =
 func getTypeof(e: NimNode): NimNode =
   newCall("typeof", e)
 
+proc rewriteEachEle(e: NimNode; bracketNode = nnkBracket): NimNode =
+  result = newNimNode bracketNode
+  for i in e:
+    result.add i.toPyExpr
+
 template mapEleCall(
   initCall, e: NimNode;
   bracketNode = nnkBracket,
@@ -94,9 +99,7 @@ template mapEleCall(
      with original `PyTComplex` type (a.k.a. being regarded as a new type)
   ]#
   e.asisIfEmpty
-  var res = newNimNode bracketNode
-  for i in e:
-    res.add i.toPyExpr
+  let res = rewriteEachEle(e, bracketNode)
   let eleTyp = getTypeof res[0]
   newCall(
     nnkBracketExpr.newTree(
@@ -137,7 +140,7 @@ proc toDict(e): NimNode =
   )
 
 
-proc toPyExpr*(atm: NimNode): NimNode =
+template toPyExprImpl(atm: NimNode; toListCb): NimNode =
   case atm.kind
   of nnkBracketExpr:
     rewriteSliceInBracket atm
@@ -151,8 +154,12 @@ proc toPyExpr*(atm: NimNode): NimNode =
   # NOTE: f"xxx" does perform `translateEscape`
   #  so we don't perform translation here
 
-  of nnkBracket:    atm.toList
+  of nnkBracket:    atm.toListCb
   of nnkCurly:      atm.toSet
   of nnkTableConstr:atm.toDict
   else:
     atm
+
+proc toPyExpr*(atm: NimNode): NimNode = toPyExprImpl atm, toList
+proc toPyExprNoList*(atm: NimNode): NimNode = toPyExprImpl atm, rewriteEachEle
+

src/pylib/pysugar/stmt/tonim.nim

@@ -75,17 +75,19 @@ proc parsePyStmt*(mparser; statement: NimNode): NimNode =
         result.add newVarStmt(varName, varValue)
         mparser.add $varName
 
-    let (varName, varValue) = (statement[0], statement[1].toPyExpr)
+    let (varName, varValue) = (statement[0], statement[1])
     case varName.kind
     of nnkIdent:
-      handleVar varName, varValue
+      handleVar varName, varValue.toPyExpr
     of nnkTupleConstr:
-      unpackImplRec(data=varValue, symbols=varName, res=result, receiver=handleVar)
+      # no need to construct list if meeting `nnkBracket`
+      unpackImplRec(data=varValue.toPyExprNoList,
+        symbols=varName, res=result, receiver=handleVar)
     of nnkBracketExpr:
-      result.add newAssignment(varName.toPyExpr, varValue)
+      result.add newAssignment(varName.toPyExpr, varValue.toPyExpr)
     else:
       # varName may be `nnkDotExpr`. e.g.`a.b=1`
-      result.add statement.copyNimNode.add(varName, varValue)
+      result.add statement.copyNimNode.add(varName, varValue.toPyExpr)
   of nnkCommand:
     let preCmd = $statement[0]
     case preCmd