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Introduce template withValue() for tables.nim too.

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cheatfate 2016-05-27 01:00:05 +03:00
commit 49c50e4e21
1 changed files with 45 additions and 0 deletions
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45
lib/pure/collections/tables.nim
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@ -136,6 +136,51 @@ proc mget*[A, B](t: var Table[A, B], key: A): var B {.deprecated.} =
proc getOrDefault*[A, B](t: Table[A, B], key: A): B = getOrDefaultImpl(t, key) proc getOrDefault*[A, B](t: Table[A, B], key: A): B = getOrDefaultImpl(t, key)
template withValue*[A, B](t: var Table[A, B], key: A,
value, body: untyped) =
## retrieves the value at ``t[key]``.
## `value` can be modified in the scope of the ``withValue`` call.
##
## .. code-block:: nim
##
## sharedTable.withValue(key, value) do:
## # block is executed only if ``key`` in ``t``
## value.name = "username"
## value.uid = 1000
##
mixin rawGet
var hc: Hash
var index = rawGet(t, key, hc)
let hasKey = index >= 0
if hasKey:
var value {.inject.} = addr(t.data[index].val)
body
template withValue*[A, B](t: var Table[A, B], key: A,
value, body1, body2: untyped) =
## retrieves the value at ``t[key]``.
## `value` can be modified in the scope of the ``withValue`` call.
##
## .. code-block:: nim
##
## table.withValue(key, value) do:
## # block is executed only if ``key`` in ``t``
## value.name = "username"
## value.uid = 1000
## do:
## # block is executed when ``key`` not in ``t``
## raise newException(KeyError, "Key not found")
##
mixin rawGet
var hc: Hash
var index = rawGet(t, key, hc)
let hasKey = index >= 0
if hasKey:
var value {.inject.} = addr(t.data[index].val)
body1
else:
body2
iterator allValues*[A, B](t: Table[A, B]; key: A): B = iterator allValues*[A, B](t: Table[A, B]; key: A): B =
## iterates over any value in the table `t` that belongs to the given `key`. ## iterates over any value in the table `t` that belongs to the given `key`.
var h: Hash = hash(key) and high(t.data) var h: Hash = hash(key) and high(t.data)