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| -rw-r--r-- | doc/manual.rst | 36 |
1 files changed, 20 insertions, 16 deletions
diff --git a/doc/manual.rst b/doc/manual.rst index 8771f8fe9..d9112652b 100644 --- a/doc/manual.rst +++ b/doc/manual.rst @@ -5153,35 +5153,39 @@ types that will match the type param: The constraint can be a concrete type or a type class. -type operator -------------- -You can obtain the type of a given expression by constructing a ``type`` +typeof operator +--------------- + +**Note**: ``typeof(x)`` can also be written as ``type(x)``. + +You can obtain the type of a given expression by constructing a ``typeof`` value from it (in many other languages this is known as the `typeof`:idx: operator): .. code-block:: nim - var x = 0 - var y: type(x) # y has type int - -You may add a constraint to the resulting type to trigger a compile-time error -if the expression doesn't have the expected type: -.. code-block:: nim var x = 0 - var y: type[object](x) # Error: type mismatch: got <int> but expected 'object' + var y: typeof(x) # y has type int -If ``type`` is used to determine the result type of a proc/iterator/converter + +If ``typeof`` 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: +other interpretations, but this behavior can be changed by +passing ``typeOfProc`` as the second argument to ``typeof``: .. code-block:: nim - import strutils + :test: "nim c $1" + + iterator split(s: string): string = discard + proc split(s: string): seq[string] = discard + + # since an iterator is the preferred interpretation, `y` has the type ``string``: + assert typeof("a b c".split) is string + + assert typeof("a b c".split, typeOfProc) is seq[string] - # 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) Modules |