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< title > cons< / title >
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< div class = "section" lang = "en" >
< div class = "titlepage" > < div > < div > < h3 class = "title" >
< a name = "fusion.container.cons" > < / a > < a href = "cons.html" title = "cons" > cons< / a > < / h3 > < / div > < / div > < / div >
< a name = "fusion.container.cons.description" > < / a > < h4 >
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< a name = "id527528" > < / a >
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< a href = "cons.html#fusion.container.cons.description" > Description< / a >
< / h4 >
< p >
< tt class = "computeroutput" > < span class = "identifier" > cons< / span > < / tt > is a simple < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward
Sequence< / a > . It is a lisp style recursive list structure where < tt class = "computeroutput" > < span class = "identifier" > car< / span > < / tt > is the < span class = "emphasis" > < em > head< / em > < / span > and
< tt class = "computeroutput" > < span class = "identifier" > cdr< / span > < / tt > is the < span class = "emphasis" > < em > tail< / em > < / span > :
usually another cons structure or < tt class = "computeroutput" > < span class = "identifier" > nil< / span > < / tt > :
the empty list. Fusion's < a href = "list.html" title = "list" > < tt class = "computeroutput" > < span class = "identifier" > list< / span > < / tt > < / a > is built on top of this more
primitive data structure. It is more efficient than < a href = "vector.html" title = "vector" > < tt class = "computeroutput" > < span class = "identifier" > vector< / span > < / tt > < / a > when the target sequence
is constructed piecemeal (a data at a time). The runtime cost of access to
each element is peculiarly constant (see < a href = "../notes.html#fusion.notes.recursive_inlined_functions" > Recursive
Inlined Functions< / a > ).
< / p >
< a name = "fusion.container.cons.header" > < / a > < h4 >
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< a name = "id527672" > < / a >
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< a href = "cons.html#fusion.container.cons.header" > Header< / a >
< / h4 >
< pre class = "programlisting" >
< span class = "preprocessor" > #include< / span > < span class = "special" > < < / span > < span class = "identifier" > boost< / span > < span class = "special" > /< / span > < span class = "identifier" > fusion< / span > < span class = "special" > /< / span > < span class = "identifier" > container< / span > < span class = "special" > /< / span > < span class = "identifier" > list< / span > < span class = "special" > /< / span > < span class = "identifier" > cons< / span > < span class = "special" > .< / span > < span class = "identifier" > hpp< / span > < span class = "special" > > < / span >
< span class = "preprocessor" > #include< / span > < span class = "special" > < < / span > < span class = "identifier" > boost< / span > < span class = "special" > /< / span > < span class = "identifier" > fusion< / span > < span class = "special" > /< / span > < span class = "identifier" > include< / span > < span class = "special" > /< / span > < span class = "identifier" > cons< / span > < span class = "special" > .< / span > < span class = "identifier" > hpp< / span > < span class = "special" > > < / span >
< / pre >
< a name = "fusion.container.cons.synopsis" > < / a > < h4 >
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< a name = "id527840" > < / a >
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< a href = "cons.html#fusion.container.cons.synopsis" > Synopsis< / a >
< / h4 >
< pre class = "programlisting" >
< span class = "keyword" > template< / span > < span class = "special" > < < / span > < span class = "keyword" > typename< / span > < span class = "identifier" > Car< / span > < span class = "special" > ,< / span > < span class = "keyword" > typename< / span > < span class = "identifier" > Cdr< / span > < span class = "special" > =< / span > < span class = "identifier" > nil< / span > < span class = "special" > > < / span >
< span class = "keyword" > struct< / span > < span class = "identifier" > cons< / span > < span class = "special" > ;< / span >
< / pre >
< a name = "fusion.container.cons.template_parameters" > < / a > < h4 >
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< a name = "id527949" > < / a >
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< a href = "cons.html#fusion.container.cons.template_parameters" > Template parameters< / a >
< / h4 >
< div class = "informaltable" > < table class = "table" >
< colgroup >
< col >
< col >
< col >
< / colgroup >
< thead > < tr >
< th >
< p >
Parameter
< / p >
< / th >
< th >
< p >
Description
< / p >
< / th >
< th >
< p >
Default
< / p >
< / th >
< / tr > < / thead >
< tbody >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > Car< / span > < / tt >
< / p >
< / td >
< td >
< p >
Head type
< / p >
< / td >
< td >
< p >
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > Cdr< / span > < / tt >
< / p >
< / td >
< td >
< p >
Tail type
< / p >
< / td >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > nil< / span > < / tt >
< / p >
< / td >
< / tr >
< / tbody >
< / table > < / div >
< a name = "fusion.container.cons.model_of" > < / a > < h4 >
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< a name = "id528099" > < / a >
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< a href = "cons.html#fusion.container.cons.model_of" > Model of< / a >
< / h4 >
< div class = "itemizedlist" > < ul type = "disc" > < li > < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward Sequence< / a > < / li > < / ul > < / div >
< div class = "variablelist" >
< p class = "title" > < b > Notation< / b > < / p >
< dl >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > nil< / span > < / tt > < / span > < / dt >
< dd > < p >
An empty < tt class = "computeroutput" > < span class = "identifier" > cons< / span > < / tt >
< / p > < / dd >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > C< / span > < / tt > < / span > < / dt >
< dd > < p >
A < tt class = "computeroutput" > < span class = "identifier" > cons< / span > < / tt > type
< / p > < / dd >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > l< / span > < / tt > ,
< tt class = "computeroutput" > < span class = "identifier" > l2< / span > < / tt > < / span > < / dt >
< dd > < p >
Instances of < tt class = "computeroutput" > < span class = "identifier" > cons< / span > < / tt >
< / p > < / dd >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > car< / span > < / tt > < / span > < / dt >
< dd > < p >
An arbitrary data
< / p > < / dd >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > cdr< / span > < / tt > < / span > < / dt >
< dd > < p >
Another < tt class = "computeroutput" > < span class = "identifier" > cons< / span > < / tt > list
< / p > < / dd >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > s< / span > < / tt > < / span > < / dt >
< dd > < p >
A < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward Sequence< / a >
< / p > < / dd >
< dt > < span class = "term" > < tt class = "computeroutput" > < span class = "identifier" > N< / span > < / tt > < / span > < / dt >
< dd > < p >
An < a href = "http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target = "_top" > MPL
Integral Constant< / a >
< / p > < / dd >
< / dl >
< / div >
< a name = "fusion.container.cons.expression_semantics" > < / a > < h4 >
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< a name = "id528380" > < / a >
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< a href = "cons.html#fusion.container.cons.expression_semantics" > Expression Semantics< / a >
< / h4 >
< p >
Semantics of an expression is defined only where it differs from, or is not
defined in < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward
Sequence< / a > .
< / p >
< div class = "informaltable" > < table class = "table" >
< colgroup >
< col >
< col >
< / colgroup >
< thead > < tr >
< th >
< p >
Expression
< / p >
< / th >
< th >
< p >
Semantics
< / p >
< / th >
< / tr > < / thead >
< tbody >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > nil< / span > < span class = "special" > ()< / span > < / tt >
< / p >
< / td >
< td >
< p >
Creates an empty list.
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > C< / span > < span class = "special" > ()< / span > < / tt >
< / p >
< / td >
< td >
< p >
Creates a cons with default constructed elements.
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > C< / span > < span class = "special" > (< / span > < span class = "identifier" > car< / span > < span class = "special" > )< / span > < / tt >
< / p >
< / td >
< td >
< p >
Creates a cons with < tt class = "computeroutput" > < span class = "identifier" > car< / span > < / tt >
head and default constructed tail.
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > C< / span > < span class = "special" > (< / span > < span class = "identifier" > car< / span > < span class = "special" > ,< / span >
< span class = "identifier" > cdr< / span > < span class = "special" > )< / span > < / tt >
< / p >
< / td >
< td >
< p >
Creates a cons with < tt class = "computeroutput" > < span class = "identifier" > car< / span > < / tt >
head and < tt class = "computeroutput" > < span class = "identifier" > cdr< / span > < / tt > tail.
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > C< / span > < span class = "special" > (< / span > < span class = "identifier" > s< / span > < span class = "special" > )< / span > < / tt >
< / p >
< / td >
< td >
< p >
Copy constructs a cons from a < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward
Sequence< / a > , < tt class = "computeroutput" > < span class = "identifier" > s< / span > < / tt > .
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < span class = "identifier" > l< / span > < span class = "special" > =< / span >
< span class = "identifier" > s< / span > < / tt >
< / p >
< / td >
< td >
< p >
Assigns to a cons, < tt class = "computeroutput" > < span class = "identifier" > l< / span > < / tt > ,
from a < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward
Sequence< / a > , < tt class = "computeroutput" > < span class = "identifier" > s< / span > < / tt > .
< / p >
< / td >
< / tr >
< tr >
< td >
< p >
< tt class = "computeroutput" > < a href = "../sequence/intrinsic/functions/at.html" title = "at" > < tt class = "computeroutput" > < span class = "identifier" > at< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "identifier" > N< / span > < span class = "special" > > (< / span > < span class = "identifier" > l< / span > < span class = "special" > )< / span > < / tt >
< / p >
< / td >
< td >
< p >
The Nth element from the beginning of the sequence; see < a href = "../sequence/intrinsic/functions/at.html" title = "at" > < tt class = "computeroutput" > < span class = "identifier" > at< / span > < / tt > < / a > .
< / p >
< / td >
< / tr >
< / tbody >
< / table > < / div >
< div class = "sidebar" > < p >
< span class = "inlinemediaobject" > < img src = "../../images/note.png" alt = "note" > < / span > < tt class = "computeroutput" > < a href = "../sequence/intrinsic/functions/at.html" title = "at" > < tt class = "computeroutput" > < span class = "identifier" > at< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "identifier" > N< / span > < span class = "special" > > (< / span > < span class = "identifier" > l< / span > < span class = "special" > )< / span > < / tt > is provided
for convenience and compatibility with the original < a href = "http://www.boost.org/libs/tuple/doc/tuple_users_guide.html" target = "_top" > Boost.Tuple< / a >
library, despite < tt class = "computeroutput" > < span class = "identifier" > cons< / span > < / tt > being
a < a href = "../sequence/concepts/forward_sequence.html" title = "Forward
Sequence">Forward Sequence< / a >
only (< tt class = "computeroutput" > < span class = "identifier" > at< / span > < / tt > is supposed to be
a < a href = "../sequence/concepts/random_access_sequence.html" title = "Random
Access Sequence">Random
Access Sequence< / a > requirement). The runtime complexity of < a href = "../sequence/intrinsic/functions/at.html" title = "at" > < tt class = "computeroutput" > < span class = "identifier" > at< / span > < / tt > < / a > is constant (see < a href = "../notes.html#fusion.notes.recursive_inlined_functions" > Recursive
Inlined Functions< / a > ).
< / p > < / div >
< a name = "fusion.container.cons.example" > < / a > < h4 >
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< a name = "id529030" > < / a >
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< a href = "cons.html#fusion.container.cons.example" > Example< / a >
< / h4 >
< pre class = "programlisting" >
< span class = "identifier" > cons< / span > < span class = "special" > < < / span > < span class = "keyword" > int< / span > < span class = "special" > ,< / span > < span class = "identifier" > cons< / span > < span class = "special" > < < / span > < span class = "keyword" > float< / span > < span class = "special" > > < / span > < span class = "special" > > < / span > < span class = "identifier" > l< / span > < span class = "special" > (< / span > < span class = "number" > 12< / span > < span class = "special" > ,< / span > < span class = "identifier" > cons< / span > < span class = "special" > < < / span > < span class = "keyword" > float< / span > < span class = "special" > > (< / span > < span class = "number" > 5.5f< / span > < span class = "special" > ));< / span >
< span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > cout< / span > < span class = "special" > < < < / span > < a href = "../sequence/intrinsic/functions/at_c.html" title = "at_c" > < tt class = "computeroutput" > < span class = "identifier" > at_c< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "number" > 0< / span > < span class = "special" > > (< / span > < span class = "identifier" > l< / span > < span class = "special" > )< / span > < span class = "special" > < < < / span > < span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > endl< / span > < span class = "special" > ;< / span >
< span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > cout< / span > < span class = "special" > < < < / span > < a href = "../sequence/intrinsic/functions/at_c.html" title = "at_c" > < tt class = "computeroutput" > < span class = "identifier" > at_c< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "number" > 1< / span > < span class = "special" > > (< / span > < span class = "identifier" > l< / span > < span class = "special" > )< / span > < span class = "special" > < < < / span > < span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > endl< / span > < span class = "special" > ;< / span >
< / pre >
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< table xmlns:rev = "http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width = "100%" > < tr >
< td align = "left" > < / td >
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< td align = "right" > < div class = "copyright-footer" > < small > Copyright <20> 2001-2007 Joel de Guzman, Dan Marsden, Tobias
Schwinger< p >
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at < a href = "http://www.boost.org/LICENSE_1_0.txt" target = "_top" > http://www.boost.org/LICENSE_1_0.txt< / a > )
< / p > < / small > < / div > < / td >
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< / tr > < / table >
< hr >
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