bugfix: overloading resolution for typeof

compiler/sem.nim

@@ -35,7 +35,7 @@ proc semStmtScope(c: PContext, n: PNode): PNode
 
 type 
   TExprFlag = enum 
-    efAllowType, efLValue, efWantIterator
+    efAllowType, efLValue, efWantIterator, efInTypeof
   TExprFlags = set[TExprFlag]
 
 proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode

compiler/semcall.nim

@@ -35,6 +35,8 @@ proc semDirectCallWithBinding(c: PContext, n, f: PNode, filter: TSymKinds,
       z.calleeSym = sym
       matches(c, n, z)
       if z.state == csMatch: 
+        # little hack so that iterators are preferred over everything else:
+        if sym.kind == skIterator: inc(z.exactMatches, 200)
         case x.state
         of csEmpty, csNoMatch: x = z
         of csMatch: 
@@ -48,7 +50,7 @@ proc semDirectCallWithBinding(c: PContext, n, f: PNode, filter: TSymKinds,
     # do not generate an error yet; the semantic checking will check for
     # an overloaded () operator
   elif y.state == csMatch and cmpCandidates(x, y) == 0 and
-      not sameMethodDispatcher(x.calleeSym, y.calleeSym): 
+      not sameMethodDispatcher(x.calleeSym, y.calleeSym):
     if x.state != csMatch: 
       InternalError(n.info, "x.state is not csMatch") 
     LocalError(n.Info, errGenerated, msgKindToString(errAmbiguousCallXYZ) % [

compiler/semexprs.nim

@@ -445,13 +445,15 @@ proc analyseIfAddressTakenInCall(c: PContext, n: PNode) =
       n.sons[i] = analyseIfAddressTaken(c, n.sons[i])
   
 proc semDirectCallAnalyseEffects(c: PContext, n: PNode,
-                                 flags: TExprFlags): PNode = 
-  var symflags = {skProc, skMethod, skConverter}
+                                 flags: TExprFlags): PNode =
   if efWantIterator in flags:
-    # for ``type countup(1,3)``, see ``tests/ttoseq``.
-    symflags = {skIterator}
-  result = semDirectCall(c, n, symflags)
-  if result != nil: 
+    result = semDirectCall(c, n, {skIterator})
+  elif efInTypeOf in flags:
+    # for ``type(countup(1,3))``, see ``tests/ttoseq``.
+    result = semDirectCall(c, n, {skIterator, skProc, skMethod, skConverter})
+  else:
+    result = semDirectCall(c, n, {skProc, skMethod, skConverter})
+  if result != nil:
     if result.sons[0].kind != nkSym: 
       InternalError("semDirectCallAnalyseEffects")
     var callee = result.sons[0].sym

compiler/semtypes.nim

@@ -625,23 +625,15 @@ proc semGeneric(c: PContext, n: PNode, s: PSym, prev: PType): PType =
     if s.ast == nil: GlobalError(n.info, errCannotInstantiateX, s.name.s)
     result = instGenericContainer(c, n, result)
 
-proc FixupRemainingGenericInvokations(c: PContext, n: PNode, 
-                                      typ: PType): PType =
-  if typ.kind == tyGenericInvokation:
-    nil
-  else:
-    result = typ
-
 proc semTypeNode(c: PContext, n: PNode, prev: PType): PType = 
   result = nil
   if gCmd == cmdIdeTools: suggestExpr(c, n)
   case n.kind
   of nkEmpty: nil
-  of nkTypeOfExpr: 
-    # for ``type countup(1,3)``, see ``tests/ttoseq``.
-    # XXX We should find a better solution.
+  of nkTypeOfExpr:
+    # for ``type(countup(1,3))``, see ``tests/ttoseq``.
     checkSonsLen(n, 1)
-    result = semExprWithType(c, n.sons[0], {efWantIterator}).typ
+    result = semExprWithType(c, n.sons[0], {efInTypeof}).typ
   of nkPar: 
     if sonsLen(n) == 1: result = semTypeNode(c, n.sons[0], prev)
     else: GlobalError(n.info, errTypeExpected)

compiler/sigmatch.nim

@@ -18,7 +18,7 @@ type
   TCandidateState* = enum 
     csEmpty, csMatch, csNoMatch
   TCandidate* {.final.} = object 
-    exactMatches: int
+    exactMatches*: int
     subtypeMatches: int
     intConvMatches: int      # conversions to int are not as expensive
     convMatches: int

doc/manual.txt

@@ -435,7 +435,7 @@ have no side-effect can be used in constant expressions too:
 
 The rules for compile-time computability are: 
 
-1. Literals are compile-time computable.
+1. Literals are compile-time computable.
 2. Type conversions are compile-time computable.
 3. Procedure calls of the form ``p(X)`` are compile-time computable if
    ``p`` is a proc without side-effects (see the `noSideEffect pragma`_ 
@@ -1294,14 +1294,14 @@ algorithm (in pseudo-code) determines type equality:
 
 Since types are graphs which can have cycles, the above algorithm needs an
 auxiliary set ``s`` to detect this case.
-
-
+
+
 Type equality modulo type distinction
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The following algorithm (in pseudo-code) determines whether two types
-are equal with no respect to ``distinct`` types. For brevity the cycle check
-with an auxiliary set ``s`` is omitted:
+The following algorithm (in pseudo-code) determines whether two types
+are equal with no respect to ``distinct`` types. For brevity the cycle check
+with an auxiliary set ``s`` is omitted:
 
 .. code-block:: nimrod
   proc typeEqualsOrDistinct(a, b: PType): bool =
@@ -1324,15 +1324,15 @@ with an auxiliary set ``s`` is omitted:
           for i in 0..a.tupleLen-1:
             if not typeEqualsOrDistinct(a[i], b[i]): return false
           result = true
-      of distinct:
-        result = typeEqualsOrDistinct(a.baseType, b.baseType)
+      of distinct:
+        result = typeEqualsOrDistinct(a.baseType, b.baseType)
       of object, enum:
         result = a == b
       of proc:
         result = typeEqualsOrDistinct(a.parameterTuple, b.parameterTuple) and
                  typeEqualsOrDistinct(a.resultType, b.resultType) and
-                 a.callingConvention == b.callingConvention
-    elif a.kind == distinct:
+                 a.callingConvention == b.callingConvention
+    elif a.kind == distinct:
       result = typeEqualsOrDistinct(a.baseType, b)
     elif b.kind == distinct:
       result = typeEqualsOrDistinct(a, b.baseType)
@@ -1413,10 +1413,10 @@ The convertible relation can be relaxed by a user-defined type
   # you can use the explicit form too
   x = chr.toInt
   echo x # => 97
-
-The type conversion ``T(a)`` is an L-value if ``a`` is an L-value and 
+
+The type conversion ``T(a)`` is an L-value if ``a`` is an L-value and 
 ``typeEqualsOrDistinct(T, type(a))`` holds.
-
+
 
 Assignment compatibility
 ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1460,7 +1460,8 @@ statements always have to be intended::
   complexStmt ::= ifStmt | whileStmt | caseStmt | tryStmt | forStmt
                    | blockStmt | asmStmt
                    | procDecl | iteratorDecl | macroDecl | templateDecl
-                   | constSection | typeSection | whenStmt | varSection
+                   | constSection | letSection 
+                   | typeSection | whenStmt | varSection
 
 
 
@@ -1474,26 +1475,26 @@ Syntax::
 Example:
 
 .. code-block:: nimrod
-  proc p(x, y: int): int {.optional.} = 
-    return x + y
+  proc p(x, y: int): int {.optional.} = 
+    return x + y
 
   discard p(3, 4) # discard the return value of `p`
 
 The `discard`:idx: statement evaluates its expression for side-effects and
-throws the expression's resulting value away. 
-
-Ignoring the return value of a procedure without using a discard statement is
-a static error.
-
-The return value can be ignored implicitely if the called proc/iterator has
-been declared with the `discardable`:idx: pragma: 
-
-.. code-block:: nimrod
-  proc p(x, y: int): int {.discardable.} = 
-    return x + y
-    
-  p(3, 4) # now valid
-
+throws the expression's resulting value away. 
+
+Ignoring the return value of a procedure without using a discard statement is
+a static error.
+
+The return value can be ignored implicitely if the called proc/iterator has
+been declared with the `discardable`:idx: pragma: 
+
+.. code-block:: nimrod
+  proc p(x, y: int): int {.discardable.} = 
+    return x + y
+    
+  p(3, 4) # now valid
+
 
 Var statement
 ~~~~~~~~~~~~~
@@ -2430,6 +2431,18 @@ be used to get the type of an expression:
   var x = 0
   var y: type(x) # y has type int
 
+If ``type`` is used to determine the result type of a proc/iterator/converter
+call ``c(X)`` (where ``X`` stands for a possibly empty list of arguments), the
+interpretation where ``c`` is an iterator is preferred over the
+other interpretations:
+
+.. code-block:: nimrod
+  import strutils
+  
+  # strutils contains both a ``split`` proc and iterator, but since an
+  # an iterator is the preferred interpretation, `y` has the type ``string``:
+  var y: type("a b c".split)
+
 
 Type constraints
 ~~~~~~~~~~~~~~~~
@@ -2979,16 +2992,16 @@ only consist of an assembler statement.
 error pragma
 ------------
 The `error`:idx: pragma is used to make the compiler output an error message
-with the given content. Compilation does not necessarily abort after an error
-though. 
-
-The ``error`` pragma can also be used to
-annotate a symbol (like an iterator or proc). The *usage* of the symbol then
-triggers a compile-time error. This is especially useful to rule out that some
-operation is valid due to overloading and type conversions: 
-
-.. code-block:: nimrod
-  ## check that underlying int values are compared and not the pointers:
+with the given content. Compilation does not necessarily abort after an error
+though. 
+
+The ``error`` pragma can also be used to
+annotate a symbol (like an iterator or proc). The *usage* of the symbol then
+triggers a compile-time error. This is especially useful to rule out that some
+operation is valid due to overloading and type conversions: 
+
+.. code-block:: nimrod
+  ## check that underlying int values are compared and not the pointers:
   proc `==`(x, y: ptr int): bool {.error.}
 
 
@@ -3308,6 +3321,7 @@ Memory allocation requires no lock at all! This design easily scales to massive
 multicore processors that will become the norm in the future.
 
 
+
 Thread pragma
 -------------
 
@@ -3402,24 +3416,24 @@ The interaction between threads and exceptions is simple: A *handled* exception
 in one thread cannot affect any other thread. However, an *unhandled* 
 exception in one thread terminates the whole *process*!
 
-Taint mode
-==========
-
-The Nimrod compiler and most parts of the standard library support 
-a `taint mode`:idx:. Input strings are declared with the `TaintedString`:idx: 
-string type declared in the ``system`` module.
-
-If the taint mode is turned on (via the ``--taintMode:on`` command line 
-option) it is a distinct string type which helps to detect input
-validation errors:
-
-.. code-block:: nimrod
-  echo "your name: "
-  var name: TaintedString = stdin.readline
-  # it is safe here to output the name without any input validation, so
-  # we simply convert `name` to string to make the compiler happy: 
-  echo "hi, ", name.string
-
-If the taint mode is turned off, ``TaintedString`` is simply an alias for
-``string``.
-
+Taint mode
+==========
+
+The Nimrod compiler and most parts of the standard library support 
+a `taint mode`:idx:. Input strings are declared with the `TaintedString`:idx: 
+string type declared in the ``system`` module.
+
+If the taint mode is turned on (via the ``--taintMode:on`` command line 
+option) it is a distinct string type which helps to detect input
+validation errors:
+
+.. code-block:: nimrod
+  echo "your name: "
+  var name: TaintedString = stdin.readline
+  # it is safe here to output the name without any input validation, so
+  # we simply convert `name` to string to make the compiler happy: 
+  echo "hi, ", name.string
+
+If the taint mode is turned off, ``TaintedString`` is simply an alias for
+``string``.
+

tests/accept/run/ttoseq.nim

@@ -10,3 +10,10 @@ template toSeq*(iter: expr): expr =
 for x in items(toSeq(countup(2, 6))): 
   stdout.write(x)
 
+import strutils
+
+var y: type("a b c".split)
+y = "xzy"
+
+
+