mirrors/eiffel-org
1
0
Fork 0
mirror of https://github.com/EiffelSoftware/eiffel-org.git synced 2025-12-07 23:32:42 +01:00
Code Issues Packages Projects Releases Wiki Activity

Author:bmeyer

Browse Source 
Date:2014-02-12T17:17:34.000000Z


git-svn-id: https://svn.eiffel.com/eiffel-org/trunk@1260 abb3cda0-5349-4a8f-a601-0c33ac3a8c38
This commit is contained in:
bmeyer
2014-02-12 17:17:34 +00:00
parent 10bfd79ee3
commit ab3d8466ba
1 changed files with 290 additions and 296 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
documentation/current/solutions/basic-computing/eiffelbase/eiffelbase-tutorial/eiffelbase-data-structures-overview/eiffelbase-iteration.wiki
View File

@@ -5,7 +5,7 @@ The classes of the Iteration cluster encapsulate control structures representing
=Iterators and Agents=
The recent introduction of the agents mechanism in Eiffel offers an attractive alternative to the <eiffel>Iterator</eiffel> cluster of EiffelBase.
Eiffel's agent mechanism offers an attractive alternative to the <eiffel>Iterator</eiffel> cluster of EiffelBase.
=The Notion of iterator=
@@ -51,11 +51,6 @@ The classes of the Iteration library address this need. Using them offers two be
=Simple Examples=
To get a first grasp of how one can work with the Iteration library, let us look at a typical iteration class and a typical iteration client.
==An example iterator routine==
@@ -277,7 +272,6 @@ The class effects all the deferred features inherited from [[ref:/libraries/base
-- test.
do
from
target.start
invariant
invariant_value
@@ -303,7 +297,7 @@ This routine text relies on features <eiffel>start</eiffel>, <eiffel>forth</eiff
and similarly for the others. <br/>
In addition to effecting the general iteration features from [[ref:/libraries/base/reference/iterator_chart|ITERATOR]] , class [[ref:/libraries/base/reference/linear_iterator_chart|LINEAR_ITERATOR]] introduces iteration features that apply to the specific case of linear structures:
* <eiffel>search </eiffel> <code> ( b :BOOLEAN) moves the iteration to the first position satisfying test if b is true, or not satisfying test if b </code> is false. This use of a boolean argument to switch between two opposite semantics is not part of the recommended style, and you will find few if any other examples in the Base libraries. Here, however, it was deemed preferable to the alternative, which would have involved four separate procedures (if together with <eiffel>search</eiffel> we consider <eiffel>continue_search</eiffel> discussed next).
* <eiffel>search (b :BOOLEAN)</eiffel> moves the iteration to the first position satisfying test if <code>b</code> is true, or not satisfying test if <code>b</code> is false. This use of a boolean argument to switch between two opposite semantics is not part of the recommended style, and you will find few if any other examples in the Base libraries. Here, however, it was deemed preferable to the alternative, which would have involved four separate procedures (if together with <eiffel>search</eiffel> we consider <eiffel>continue_search</eiffel> discussed next).
* With a linear structure we can implement an iteration corresponding to the 'for' loop of traditional programming languages, defined by three integers: the starting position, the number of items to be traversed, and the step between consecutive items. This is provided by procedure <eiffel>do_for</eiffel> <code> ( starting , number , step :INTEGER). </code>
* Since with a linear target the iterator can advance the cursor step by step, the basic iteration operations are complemented by variants which pick up from the position reached by the last call: <eiffel>continue_until</eiffel>, <eiffel>until_continue</eiffel>, <eiffel>continue_while</eiffel>, <eiffel>while_continue</eiffel>, <eiffel>continue_search</eiffel>, <eiffel>continue_for</eiffel>.