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| -rw-r--r-- | doc/tut1.txt | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/doc/tut1.txt b/doc/tut1.txt index 23d8a9b57..0d2de3c1e 100644 --- a/doc/tut1.txt +++ b/doc/tut1.txt @@ -1234,8 +1234,8 @@ Example: .. code-block:: nim var - x: seq[int] # a sequence of integers - x = @[1, 2, 3, 4, 5, 6] # the @ turns the array into a sequence + x: seq[int] # a reference to a sequence of integers + x = @[1, 2, 3, 4, 5, 6] # the @ turns the array into a sequence allocated on the heap Sequence variables are initialized with ``nil``. However, most sequence operations cannot deal with ``nil`` (leading to an exception being @@ -1279,6 +1279,23 @@ The `len <system.html#len,TOpenArray>`_, `low <system.html#low>`_ and `high with a compatible base type can be passed to an openarray parameter, the index type does not matter. +.. code-block:: nim + var + fruits: seq[string] # reference to a sequence of strings that is initialized with 'nil' + capitals: array[3, string] # array of strings with a fixed size + + fruits = @[] # creates an empty sequence on the heap that will be referenced by 'fruits' + + capitals = ["New York", "London", "Berlin"] # array 'capitals' allows only assignment of three elements + fruits.add("Banana") # sequence 'fruits' is dynamically expandable during runtime + fruits.add("Mango") + + proc openArraySize(oa: openArray[string]): int = + oa.len + + assert openArraySize(fruits) == 2 # procedure accepts a sequence as parameter + assert openArraySize(capitals) == 3 # but also an array type + The openarray type cannot be nested: multidimensional openarrays are not supported because this is seldom needed and cannot be done efficiently. |