| <html><head><META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>1.2.2. Annotation</title><link href="style.css" rel="stylesheet" type="text/css"><meta content="DocBook XSL Stylesheets V1.72.0" name="generator"><link rel="start" href="index.html" title="The VIATRA2 Model Transformation Framework"><link rel="up" href="sec_MachineDefinition.html" title="1.2. Machine Definition"><link rel="prev" href="def_Machine.html" title="1.2.1. GTASM Machine Definition"><link rel="next" href="sec_GraphPatterns.html" title="2. Graph Patterns"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">1.2.2. Annotation</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="def_Machine.html">Prev</a> </td><th align="center" width="60%">1.2. Machine Definition</th><td align="right" width="20%"> <a accesskey="n" href="sec_GraphPatterns.html">Next</a></td></tr></table><hr></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="def_Annotation"></a>1.2.2. Annotation</h4></div></div></div><div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Tip: Description"><tr><td valign="top" align="center" rowspan="2" width="25"><img alt="[Tip]" src="images/tip.png"></td><th align="left"><a name="def_Annotation_Description"></a>Description</th></tr><tr><td valign="top" align="left"><p> | |
| An <span class="strong"><strong>annotation</strong></span> | |
| <a name="N10249" class="indexterm"></a> | |
| allows the transformation designers to fine-tune runtime settings. | |
| Currently, only few runtime annotations are supported in VIATRA to select | |
| the appropriate pattern matching engine, and to switch between batch and | |
| live transformations. | |
| </p></td></tr></table></div><div class="important" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Important: Syntax"><tr><td valign="top" align="center" rowspan="2" width="25"><img alt="[Important]" src="images/important.png"></td><th align="left"><a name="def_Annotation_Syntax"></a>Syntax</th></tr><tr><td valign="top" align="left"><pre class="programlisting"> | |
| OptAnnotationsAST ::= $empty | AnnotationsAST | |
| AnnotationsAST ::= AnnotationAST | |
| | AnnotationsAST AnnotationAST | |
| AnnotationAST ::= AnnotationNameAST | |
| | AnnotationNameAST <span class="token">(</span> AnnotationBodyAST <span class="token">)</span> | |
| AnnotationBodyAST ::= KeyValuePairAST | |
| | AnnotationBodyAST <span class="token">,</span> KeyValuePairAST | |
| KeyValuePairAST ::= <a href="def_ModelElementName.html" title="5.7.1. Model Element Name">TypeNameAST</a> <span class="token">=</span> <a href="def_ModelElementName.html" title="5.7.1. Model Element Name">TypeNameAST</a> | |
| AnnotationNameAST ::= <a href="def_AnnotationLiteral.html" title="6.2.5. Annotation Literal">AnnotationLiteral</a> | |
| </pre><p> | |
| An <span class="strong"><strong>annotation</strong></span> has a name which is prefixed by <code class="computeroutput">@</code>. | |
| It may have an optional body defined in the form of key-value pairs within parentheses. | |
| The keys and values are restricted well-formed <a href="def_ModelElementName.html" title="5.7.1. Model Element Name">local names</a>, | |
| although they are not required to point to actual model elements (i.e. it is only | |
| a syntactic restriction). | |
| </p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note: Semantics"><tr><td valign="top" align="center" rowspan="2" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left"><a name="def_Annotation_Semantics"></a>Semantics</th></tr><tr><td valign="top" align="left"><p> | |
| Currently, the VIATRA interpreter accepts three annotations. | |
| <div class="itemizedlist"><ul type="disc"><li><p> | |
| <code class="computeroutput">incremental</code>: this can be attached to | |
| <a href="def_GraphPatternDef.html" title="2.1.1. Graph Pattern Definition">graph pattern definitions</a>, | |
| <a href="def_Machine.html" title="1.2.1. GTASM Machine Definition">machines</a>. | |
| </p><p> | |
| In case of graph patterns, it prescribes that the annotated pattern and all dependent patterns accessed | |
| by <a href="def_PatternComposition.html" title="2.1.5. Pattern Composition">pattern composition</a> | |
| should be executed using the incremental pattern matcher engine. | |
| </p><p> | |
| When a machine is annotated, it prescribes that all patterns defined in the machine | |
| should be executed by the incremental pattern matcher. | |
| </p></li><li><code class="computeroutput">localsearch</code>: this can be also attached to | |
| <a href="def_GraphPatternDef.html" title="2.1.1. Graph Pattern Definition">graph pattern definitions</a>, | |
| <a href="def_Machine.html" title="1.2.1. GTASM Machine Definition">machines</a>. The effect of this annotation is same as | |
| above, except for selecting the local search based pattern matching engine. | |
| </li><li><p> | |
| <code class="computeroutput">trigger</code>: this can be also attached to a | |
| GT rule, and it defines that the corresponding GT rule is interpreted as a | |
| <a href="">trigger</a>. | |
| </p></li></ul></div> | |
| </p></td></tr></table></div><div class="highlights"><a name="def_Annotation_Remark"></a><p><b>Remark. </b> | |
| Note that in most cases, the incremental pattern matcher engine has | |
| significantly better performance. However, the default annotation | |
| for a pattern is <code class="computeroutput">@localsearch</code>. | |
| </p></div><div class="highlights"><a name="def_Annotation_UsedBy"></a><p><b>Used By: </b> | |
| <a href="def_GTRuleDef.html" title="3.1.1. Graph Transformation Rule Definition">GT rule definition</a>, | |
| <a href="def_GraphPatternDef.html" title="2.1.1. Graph Pattern Definition">graph pattern definition</a>, | |
| <a href="def_Machine.html" title="1.2.1. GTASM Machine Definition">machine</a> | |
| </p></div></div><div class="navfooter"><hr><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="def_Machine.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="sec_MachineDefinition.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="sec_GraphPatterns.html">Next</a></td></tr><tr><td valign="top" align="left" width="40%">1.2.1. GTASM Machine Definition </td><td align="center" width="20%"><a accesskey="h" href="index.html">Home</a></td><td valign="top" align="right" width="40%"> 2. Graph Patterns</td></tr></table></div></body></html> |