var tuple unpacking works at compile time

compiler/evals.nim

@@ -287,41 +287,52 @@ proc getNullValue(typ: PType, info: TLineInfo): PNode =
     result = newNodeIT(nkCurly, info, t)    
   else: InternalError("getNullValue: " & $t.kind)
   
-proc evalVar(c: PEvalContext, n: PNode): PNode = 
-  for i in countup(0, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    if a.kind == nkCommentStmt: continue 
-    if a.kind != nkIdentDefs: return raiseCannotEval(c, n.info)
-    # XXX var (x, y) = z support?
+proc evalVarValue(c: PEvalContext, n: PNode): PNode =
+  result = evalAux(c, n, {})
+  if result.kind in {nkType..nkNilLit}: result = result.copyNode
+
+proc evalVar(c: PEvalContext, n: PNode): PNode =
+  for i in countup(0, sonsLen(n) - 1):
+    let a = n.sons[i]
+    if a.kind == nkCommentStmt: continue
     #assert(a.sons[0].kind == nkSym) can happen for transformed vars
-    if a.sons[2].kind != nkEmpty:
-      result = evalAux(c, a.sons[2], {})
-      if result.kind in {nkType..nkNilLit}: 
+    if a.kind == nkVarTuple:
+      result = evalVarValue(c, a.lastSon)
+      if result.kind in {nkType..nkNilLit}:
         result = result.copyNode
       if isSpecial(result): return
+      if result.kind != nkPar:
+        return raiseCannotEval(c, n.info)
+      for i in 0 .. a.len-3:
+        var v = a.sons[i].sym
+        IdNodeTablePut(c.tos.mapping, v, result.sons[i])
     else:
-      result = getNullValue(a.sons[0].typ, a.sons[0].info)
-    if a.sons[0].kind == nkSym:
-      var v = a.sons[0].sym
-      IdNodeTablePut(c.tos.mapping, v, result)
-    else:
-      # assign to a.sons[0]:
-      var x = result
-      result = evalAux(c, a.sons[0], {})
-      if isSpecial(result): return 
-      myreset(x)
-      x.kind = result.kind
-      x.typ = result.typ
-      case x.kind
-      of nkCharLit..nkInt64Lit: x.intVal = result.intVal
-      of nkFloatLit..nkFloat64Lit: x.floatVal = result.floatVal
-      of nkStrLit..nkTripleStrLit: x.strVal = result.strVal
-      of nkIdent: x.ident = result.ident
-      of nkSym: x.sym = result.sym
+      if a.sons[2].kind != nkEmpty:
+        result = evalVarValue(c, a.sons[2])
+        if isSpecial(result): return
       else:
-        if x.kind notin {nkEmpty..nkNilLit}:
-          discardSons(x)
-          for j in countup(0, sonsLen(result) - 1): addSon(x, result.sons[j])
+        result = getNullValue(a.sons[0].typ, a.sons[0].info)
+      if a.sons[0].kind == nkSym:
+        var v = a.sons[0].sym
+        IdNodeTablePut(c.tos.mapping, v, result)
+      else:
+        # assign to a.sons[0]:
+        var x = result
+        result = evalAux(c, a.sons[0], {})
+        if isSpecial(result): return
+        myreset(x)
+        x.kind = result.kind
+        x.typ = result.typ
+        case x.kind
+        of nkCharLit..nkInt64Lit: x.intVal = result.intVal
+        of nkFloatLit..nkFloat64Lit: x.floatVal = result.floatVal
+        of nkStrLit..nkTripleStrLit: x.strVal = result.strVal
+        of nkIdent: x.ident = result.ident
+        of nkSym: x.sym = result.sym
+        else:
+          if x.kind notin {nkEmpty..nkNilLit}:
+            discardSons(x)
+            for j in countup(0, sonsLen(result) - 1): addSon(x, result.sons[j])
   result = emptyNode
 
 proc aliasNeeded(n: PNode, flags: TEvalFlags): bool = 

compiler/msgs.nim

@@ -798,11 +798,12 @@ proc addSourceLine*(fileIdx: int32, line: string) =
 proc sourceLine*(i: TLineInfo): PRope =
   if i.fileIndex < 0: return nil
   
-  if not optPreserveOrigSource and
-         fileInfos[i.fileIndex].lines.len == 0:
-    for line in lines(i.toFullPath):
-      addSourceLine i.fileIndex, line.string
-
+  if not optPreserveOrigSource and fileInfos[i.fileIndex].lines.len == 0:
+    try:
+      for line in lines(i.toFullPath):
+        addSourceLine i.fileIndex, line.string
+    except EIO:
+      discard
   InternalAssert i.fileIndex < fileInfos.len
   # can happen if the error points to EOF:
   if i.line > fileInfos[i.fileIndex].lines.len: return nil

compiler/semstmts.nim

@@ -380,11 +380,11 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
             # side of the '=':
             if warnShadowIdent in gNotes and not identWithin(def, v.name):
               Message(a.info, warnShadowIdent, v.name.s)
-      if def != nil and def.kind != nkEmpty:
-        # this is needed for the evaluation pass and for the guard checking:
-        v.ast = def
-        if sfThread in v.flags: LocalError(def.info, errThreadvarCannotInit)
       if a.kind != nkVarTuple:
+        if def != nil and def.kind != nkEmpty:
+          # this is needed for the evaluation pass and for the guard checking:
+          v.ast = def
+          if sfThread in v.flags: LocalError(def.info, errThreadvarCannotInit)
         v.typ = typ
         b = newNodeI(nkIdentDefs, a.info)
         if importantComments():
@@ -394,7 +394,8 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
         addSon(b, a.sons[length-2])      # keep type desc for doc generator
         addSon(b, copyTree(def))
         addSon(result, b)
-      else: 
+      else:
+        if def.kind == nkPar: v.ast = def[j]
         v.typ = tup.sons[j]
         b.sons[j] = newSymNode(v)
       checkNilable(v)

todo.txt

@@ -15,6 +15,7 @@ version 0.9.4
 Bugs
 ====
 
+- REPL: after an error no evaluation is performed for the next line
 - simple closure iterator doesn't work
 - docgen: sometimes effects are listed twice
 - 'result' is not properly cleaned for NRVO --> use uninit checking instead