use 'using' instead of 'sig' keyword; cleans up new features a bit

compiler/ast.nim

@@ -221,7 +221,6 @@ type
     nkGotoState,          # used for the state machine (for iterators)
     nkState,              # give a label to a code section (for iterators)
     nkBreakState,         # special break statement for easier code generation
-    nkSigSection
   TNodeKinds* = set[TNodeKind]
 
 type

compiler/lexer.nim

@@ -45,7 +45,7 @@ type
     tkMacro, tkMethod, tkMixin, tkMod, tkNil, tkNot, tkNotin,
     tkObject, tkOf, tkOr, tkOut,
     tkProc, tkPtr, tkRaise, tkRef, tkReturn,
-    tkShl, tkShr, tkSig, tkStatic,
+    tkShl, tkShr, tkStatic,
     tkTemplate,
     tkTry, tkTuple, tkType, tkUsing,
     tkVar, tkWhen, tkWhile, tkWith, tkWithout, tkXor,
@@ -82,7 +82,7 @@ const
     "macro", "method", "mixin", "mod",
     "nil", "not", "notin", "object", "of", "or",
     "out", "proc", "ptr", "raise", "ref", "return",
-    "shl", "shr", "sig", "static",
+    "shl", "shr", "static",
     "template",
     "try", "tuple", "type", "using",
     "var", "when", "while", "with", "without", "xor",

compiler/parser.nim

@@ -1908,7 +1908,7 @@ proc complexOrSimpleStmt(p: var TParser): PNode =
   #|                     | 'converter' routine
   #|                     | 'type' section(typeDef)
   #|                     | 'const' section(constant)
-  #|                     | ('let' | 'var') section(variable)
+  #|                     | ('let' | 'var' | 'using') section(variable)
   #|                     | bindStmt | mixinStmt)
   #|                     / simpleStmt
   case p.tok.tokType
@@ -1943,10 +1943,9 @@ proc complexOrSimpleStmt(p: var TParser): PNode =
   of tkLet: result = parseSection(p, nkLetSection, parseVariable)
   of tkWhen: result = parseIfOrWhen(p, nkWhenStmt)
   of tkVar: result = parseSection(p, nkVarSection, parseVariable)
-  of tkSig: result = parseSection(p, nkSigSection, parseVariable)
   of tkBind: result = parseBind(p, nkBindStmt)
   of tkMixin: result = parseBind(p, nkMixinStmt)
-  of tkUsing: result = parseBind(p, nkUsingStmt)
+  of tkUsing: result = parseSection(p, nkUsingStmt, parseVariable)
   else: result = simpleStmt(p)
 
 proc parseStmt(p: var TParser): PNode =

compiler/renderer.nim

@@ -460,9 +460,12 @@ proc lsub(n: PNode): int =
     else:
       result = len("enum")
   of nkEnumFieldDef: result = lsons(n) + 3
-  of nkVarSection, nkLetSection, nkSigSection:
+  of nkVarSection, nkLetSection:
     if sonsLen(n) > 1: result = MaxLineLen + 1
     else: result = lsons(n) + len("var_")
+  of nkUsingStmt:
+    if sonsLen(n) > 1: result = MaxLineLen + 1
+    else: result = lsons(n) + len("using_")
   of nkReturnStmt: result = lsub(n.sons[0]) + len("return_")
   of nkRaiseStmt: result = lsub(n.sons[0]) + len("raise_")
   of nkYieldStmt: result = lsub(n.sons[0]) + len("yield_")
@@ -1173,12 +1176,12 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext) =
     initContext(a)
     incl(a.flags, rfInConstExpr)
     gsection(g, n, a, tkConst, "const")
-  of nkVarSection, nkLetSection, nkSigSection:
+  of nkVarSection, nkLetSection, nkUsingStmt:
     var L = sonsLen(n)
     if L == 0: return
     if n.kind == nkVarSection: putWithSpace(g, tkVar, "var")
     elif n.kind == nkLetSection: putWithSpace(g, tkLet, "let")
-    else: putWithSpace(g, tkSig, "sig")
+    else: putWithSpace(g, tkUsing, "using")
     if L > 1:
       gcoms(g)
       indentNL(g)

compiler/semexprs.nim

@@ -1556,10 +1556,6 @@ proc newAnonSym(kind: TSymKind, info: TLineInfo,
   result = newSym(kind, idAnon, owner, info)
   result.flags = {sfGenSym}
 
-proc semUsing(c: PContext, n: PNode): PNode =
-  result = newNodeI(nkEmpty, n.info)
-  localError(n.info, "'using' statement is obsolete")
-
 proc semExpandToAst(c: PContext, n: PNode): PNode =
   var macroCall = n[1]
   var expandedSym = expectMacroOrTemplateCall(c, macroCall)
@@ -2354,7 +2350,6 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode =
     if not n.sons[0].typ.isEmptyType and not implicitlyDiscardable(n.sons[0]):
       localError(n.info, errGenerated, "'defer' takes a 'void' expression")
     #localError(n.info, errGenerated, "'defer' not allowed in this context")
-  of nkSigSection: result = semSigSection(c, n)
   else:
     localError(n.info, errInvalidExpressionX,
                renderTree(n, {renderNoComments}))

compiler/semstmts.nim

@@ -386,8 +386,11 @@ proc isDiscardUnderscore(v: PSym): bool =
     v.flags.incl(sfGenSym)
     result = true
 
-proc semSigSection(c: PContext; n: PNode): PNode =
+proc semUsing(c: PContext; n: PNode): PNode =
   result = ast.emptyNode
+  if not isTopLevel(c): localError(n.info, errXOnlyAtModuleScope, "using")
+  if not experimentalMode(c):
+    localError(n.info, "use the {.experimental.} pragma to enable 'using'")
   for i in countup(0, sonsLen(n)-1):
     var a = n.sons[i]
     if gCmd == cmdIdeTools: suggestStmt(c, a)
@@ -402,10 +405,10 @@ proc semSigSection(c: PContext; n: PNode): PNode =
         v.typ = typ
         strTableIncl(c.signatures, v)
     else:
-      localError(a.info, "'sig' section must have a type")
+      localError(a.info, "'using' section must have a type")
     var def: PNode
     if a.sons[length-1].kind != nkEmpty:
-      localError(a.info, "'sig' sections cannot contain assignments")
+      localError(a.info, "'using' sections cannot contain assignments")
 
 proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
   var b: PNode

compiler/wordrecg.nim

@@ -30,7 +30,7 @@ type
     wInclude, wInterface, wIs, wIsnot, wIterator, wLet,
     wMacro, wMethod, wMixin, wMod, wNil,
     wNot, wNotin, wObject, wOf, wOr, wOut, wProc, wPtr, wRaise, wRef, wReturn,
-    wShl, wShr, wSig, wStatic, wTemplate, wTry, wTuple, wType, wUsing, wVar,
+    wShl, wShr, wStatic, wTemplate, wTry, wTuple, wType, wUsing, wVar,
     wWhen, wWhile, wWith, wWithout, wXor, wYield,
 
     wColon, wColonColon, wEquals, wDot, wDotDot,
@@ -114,7 +114,7 @@ const
     "macro", "method", "mixin", "mod", "nil", "not", "notin",
     "object", "of", "or",
     "out", "proc", "ptr", "raise", "ref", "return",
-    "shl", "shr", "sig", "static",
+    "shl", "shr", "static",
     "template", "try", "tuple", "type", "using", "var",
     "when", "while", "with", "without", "xor",
     "yield",

doc/manual/stmts.txt

@@ -547,55 +547,36 @@ Instead of:
 Using statement
 ---------------
 
-**Warning**: The ``using`` statement is highly experimental and has to be
+**Warning**: The ``using`` statement is experimental and has to be
 explicitly enabled with the `experimental`:idx: pragma or command line option!
 
-The using statement provides syntactic convenience for procs that
-heavily use a single contextual parameter. When applied to a variable or a
-constant, it will instruct Nim to automatically consider the used symbol as
-a hidden leading parameter for any procedure calls, following the using
-statement in the current scope. Thus, it behaves much like the hidden `this`
-parameter available in some object-oriented programming languages.
+The using statement provides syntactic convenience in modules where
+the same parameter names and types are used over and over. Instead of:
 
 .. code-block:: nim
+  proc foo(c: Context; n: Node) = ...
+  proc bar(c: Context; n: Node, counter: int) = ...
+  proc baz(c: Context; n: Node) = ...
 
-  var s = socket()
-  using s
-
-  connect(host, port)
-  send(data)
-
-  while true:
-    let line = readLine(timeout)
-    ...
-
-
-When applied to a callable symbol, it brings the designated symbol in the
-current scope. Thus, it can be used to disambiguate between imported symbols
-from different modules having the same name.
+One can tell the compiler about the convention that a parameter of
+name ``c`` should default to type ``Context``, ``n`` should default to
+``Node`` etc.:
 
 .. code-block:: nim
-  import windows, sdl
-  using sdl.SetTimer
+  {.experimental.}
+  using
+    c: Context
+    n: Node
+    counter: int
 
-Note that ``using`` only *adds* to the current context, it doesn't remove or
-replace, **neither** does it create a new scope. What this means is that if one
-applies this to multiple variables the compiler will find conflicts in what
-variable to use:
+  proc foo(c, n) = ...
+  proc bar(c, n, counter) = ...
+  proc baz(c, n) = ...
 
-.. code-block:: nim
-  var a, b = "kill it"
-  using a
-  add(" with fire")
-  using b
-  add(" with water")
-  echo a
-  echo b
 
-When the compiler reaches the second ``add`` call, both ``a`` and ``b`` could
-be used with the proc, so one gets ``Error: expression '(a|b)' has no type (or
-is ambiguous)``. To solve this one would need to nest ``using`` with a
-``block`` statement so as to control the reach of the ``using`` statement.
+The ``using`` section uses the same indentation based grouping syntax as
+a ``var`` or ``let``` section.
+
 
 If expression
 -------------

lib/core/macros.nim

@@ -75,8 +75,7 @@ type
     nnkClosure,
     nnkGotoState,
     nnkState,
-    nnkBreakState,
-    nnkSigSection
+    nnkBreakState
 
   NimNodeKinds* = set[NimNodeKind]
   NimTypeKind* = enum

lib/packages/docutils/highlite.nim

@@ -56,7 +56,7 @@ const
     "generic", "if", "import", "in", "include",
     "interface", "is", "isnot", "iterator", "let", "macro", "method",
     "mixin", "mod", "nil", "not", "notin", "object", "of", "or", "out", "proc",
-    "ptr", "raise", "ref", "return", "shl", "shr", "sig", "static",
+    "ptr", "raise", "ref", "return", "shl", "shr", "static",
     "template", "try", "tuple", "type", "using", "var", "when", "while", "with",
     "without", "xor", "yield"]
 

tests/casestmt/tcaseexpr1.nim

@@ -11,7 +11,7 @@ discard """
 type
   E = enum A, B, C
 
-proc foo(x): auto =
+proc foo(x: int): auto =
   return case x
     of 1..9: "digit"
     else: "number"

tests/generics/tbadgenericlambda.nim

@@ -3,5 +3,5 @@ discard """
   line: 6
 """
 
-let x = proc (x, y): auto = x + y
+let x = proc (x, y: auto): auto = x + y
 

tests/generics/tgeneric0.nim

@@ -18,7 +18,7 @@ proc foo[T](p: TType[T, range[0..2]]) =
 
 #bug #1366
 
-proc reversed(x) =
+proc reversed(x: auto) =
   for i in countdown(x.low, x.high):
     echo i
 

tests/generics/tgenericlambda.nim

@@ -5,15 +5,15 @@ discard """
 proc test(x: proc (a, b: int): int) =
   echo x(5, 5)
 
-test(proc (a, b): auto = a + b)
+test(proc (a, b: auto): auto = a + b)
 
-test do (a, b) -> auto: a + b
+test do (a, b: auto) -> auto: a + b
 
 proc foreach[T](s: seq[T], body: proc(x: T)) =
   for e in s:
     body(e)
 
-foreach(@[1,2,3]) do (x):
+foreach(@[1,2,3]) do (x: auto):
   echo x
 
 proc foo =

tests/macros/tclosuremacro.nim

@@ -26,7 +26,7 @@ proc noReturn(x: () -> void) =
 proc doWithOneAndTwo(f: (int, int) -> int): int =
   f(1,2)
 
-echo twoParams(proc (a, b): auto = a + b)
+echo twoParams(proc (a, b: auto): auto = a + b)
 echo twoParams((x, y) => x + y)
 
 echo oneParam(x => x+5)

tests/misc/tupcomingfeatures.nim

@@ -0,0 +1,39 @@
+discard """
+  output: '''0 -2 0
+  0 -2'''
+"""
+
+{.this: self.}
+
+type
+  Foo {.partial.} = object
+    a, b: int
+
+type
+  tupcomingfeatures.Foo = object
+    x: int
+
+proc yay(self: Foo) =
+  echo a, " ", b, " ", x
+
+proc footest[T](self: var Foo, a: T) =
+  b = 1+a
+  yay()
+
+proc nongeneric(self: Foo) =
+  echo a, " ", b
+
+var ff: Foo
+footest(ff, -3)
+ff.nongeneric
+
+{.experimental.}
+using
+  c: Foo
+  x, y: int
+
+proc usesSig(c) =
+  echo "yummy"
+
+proc foobar(c, y) =
+  echo "yay"

tests/template/tit.nim

@@ -5,7 +5,7 @@ template someIt(a, pred: expr): expr =
   var it {.inject.} = 0
   pred
 
-proc aProc(n) =
+proc aProc(n: auto) =
   n.someIt(echo(it))
 
 aProc(89)

tests/typerel/trettypeinference.nim

@@ -5,8 +5,8 @@ discard """
 
 import typetraits
 
-proc plus(a, b): auto = a + b
-proc makePair(a, b): auto = (first: a, second: b)
+proc plus(a, b: auto): auto = a + b
+proc makePair(a, b: auto): auto = (first: a, second: b)
 
 proc `+`(a, b: string): seq[string] = @[a, b]
 
@@ -19,7 +19,7 @@ static: assert p[0].type is string
 echo i.type.name
 echo s.type.name
 
-proc inst(a): auto =
+proc inst(a: auto): auto =
   static: echo "instantiated for ", a.type.name
   result = a
 

todo.txt

@@ -1,6 +1,9 @@
 
 nim c --gc:v2 -r -d:useSysAssert -d:useGcAssert -d:smokeCycles -d:useRealtimeGc tests/gc/gcbench
 
+- document ``this`` pragma
+- document and stress test ``.partial`` object declarations
+
 essential for 1.0
 =================
 

web/news.txt

@@ -16,20 +16,34 @@ Changes affecting backwards compatibility
   ``table.mpairs`` iterator only the returned values can be modified, no
   longer the keys.
 - The deprecated Nim shebang notation ``#!`` was removed from the language. Use ``#?`` instead.
+- The ``using`` statement now means something completely different. You can use the
+  new experimental ``this`` pragma to achieve a similar effect to what the old ``using`` statement tried to achieve.
+- Typeless parameters have been removed from the language since it would
+  clash with ``using``.
 
 
 Library Additions
 -----------------
 
 - The rlocks module has been added providing reentrant lock synchronization
-  primitive
+  primitive.
 
 Compiler Additions
 ------------------
 
 - Added a new ``--noCppExceptions`` switch that allows to use default exception
   handling (no ``throw`` or ``try``/``catch`` generated) when compiling to C++
-  code
+  code.
+
+Language Additions
+------------------
+
+- Nim now supports a ``.this`` pragma for more notational convenience.
+- Nim now supports a different ``using`` statement for more convenience.
+- Nim now supports ``partial`` object declarations to mitigate the problems
+  that arise when types are mutually dependent and yet should be kept in
+  different modules.
+
 
 2016-01-27 Nim in Action is now available!
 ==========================================