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| <title>OT/J Language Definition v1.3</title> |
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| <td class="back"><a id="top"></a></td> |
| <td class="top"><a href="index.html" rel="contents">↑ Table of Contents ↑</a></td> |
| <td class="next"><a href="s4.9.2.html" rel="next">§4.9.2 Role side inheritance >></a></td> |
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| <div class="breadcrumb"><a class="nav" href="s4.html" rel="section">§4 Callin Binding</a> > <a class="nav" href="s4.9.html" rel="section">§4.9 Callin inheritance</a></div> |
| <div class="sect depth3" id="s4.9.1"> |
| <h3 class="sect">§4.9.1 Base side inheritance</h3> |
| <p> |
| Generally, a callin binding affects all sub-types of its bound base. |
| Specifically, if a role type <code>R</code> bound to a base type <code>B</code> |
| defines a callin binding <code>rm <- <i>callin_modifier</i> bm</code>, |
| the following rules apply: |
| |
| </p> |
| <div class="subsect depth4" id="s4.9.1.a"> |
| <h4 class="subsect">(a) <span class="title">Effect on sub-classes</span></h4> |
| <p>The callin binding also effects instances of any type <code>BSub</code> |
| that is a sub-type of <code>B</code>. |
| If <code>BSub</code> overrides the bound base method <code>bm</code>, |
| the overridden version is generally affected, too. |
| However, if <code>bm</code> covariantly redefines the return type from its |
| super version, the callin binding has to explicitly specify if the covariant |
| sub-class version should be affected, too (see <a href="s4.9.3.b.html" |
| title="§4.9.3.(b) Capturing covariant base methods" |
| class="sect">§4.9.3.(b)</a>). |
| |
| </p> |
| </div> |
| <div class="subsect depth4" id="s4.9.1.b"> |
| <h4 class="subsect">(b) <span class="title">No effect on super-classes</span></h4> |
| <p>The binding never affects an instance of any super-type of <code>B</code> |
| even if the method <code>bm</code> is inherited from a super-class |
| or overrides an inherited method. |
| This ensures that dispatching to a role method due to a callin binding |
| always provides a base instance that has at least the type declared in the role's |
| <code>playedBy</code> clause. |
| |
| </p> |
| </div> |
| <p> |
| For corresponding definitions regarding static methods see <a href="s4.7.e.html" title="§4.7.(e) No overriding" class="sect">§4.7.(e)</a>. |
| |
| </p> |
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| <div class="breadcrumb"><a class="nav" href="s4.html" rel="section">§4 Callin Binding</a> > <a class="nav" href="s4.9.html" rel="section">§4.9 Callin inheritance</a></div> |
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| <address>© Stephan Herrmann, Christine Hundt, Marco Mosconi</address> |
| OT/J version 1.3 — last modified: 2010-02-20 |
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