| <html><head><META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>2.1.8. Check Condition</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_PatternDefinition.html" title="2.1. Pattern Definition"><link rel="prev" href="def_PatternVariableAssignment.html" title="2.1.7. Pattern Variable Assignment"><link rel="next" href="def_ContainmentConstraint.html" title="2.1.9. Containment Constraint"></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">2.1.8. Check Condition</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="def_PatternVariableAssignment.html">Prev</a> </td><th align="center" width="60%">2.1. Pattern Definition</th><td align="right" width="20%"> <a accesskey="n" href="def_ContainmentConstraint.html">Next</a></td></tr></table><hr></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="def_CheckCondition"></a>2.1.8. Check Condition</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_CheckCondition_Description"></a>Description</th></tr><tr><td valign="top" align="left"><p> | |
| A <span class="strong"><strong>check condition</strong></span> | |
| <a name="N10848" class="indexterm"></a> | |
| is part of a | |
| <a href="def_PatternBody.html" title="2.1.2. Pattern Body">pattern body</a>. | |
| </p><p> | |
| It defines a boolean condition as an ASM term that must evaluate to true for a successful match of the | |
| pattern. | |
| </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_CheckCondition_Syntax"></a>Syntax</th></tr><tr><td valign="top" align="left"><pre class="programlisting"> | |
| CheckConditionAST ::= <span class="token">check</span> <span class="token">(</span> <a href="def_LogicalTerm.html" title="5.2.1. Logical Term">LogicalTermAST</a> <span class="token">)</span> | |
| </pre><p> | |
| A | |
| <span class="strong"><strong>check condition</strong></span> | |
| <a name="N1086D" class="indexterm"></a> | |
| is composed of the keyword and an ASM <a href="def_LogicalTerm.html" title="5.2.1. Logical Term">logical term</a> | |
| in braces. The ASM <a href="def_LogicalTerm.html" title="5.2.1. Logical Term">logical terms</a> | |
| is composed of <a href="def_PatternVariable.html" title="2.1.6. Pattern Variable">pattern variables</a>, as well as | |
| <a href="def_AsmConstant.html" title="5.4.1. ASM Constant (Value)">constants</a> | |
| and | |
| <a href="def_AsmFunctionLocation.html" title="5.5.3. ASM Function Location">ASM function locations</a>, etc. | |
| </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_CheckCondition_Semantics"></a>Semantics</th></tr><tr><td valign="top" align="left"><p> | |
| The matching of the container pattern succeeds only if this | |
| <span class="strong"><strong>check condition</strong></span> | |
| <a name="N10890" class="indexterm"></a> | |
| evaluates to | |
| <span class="emphasis"><em>true</em></span>. | |
| </p><p> | |
| From a semantic point of view, this check is carried out | |
| <span class="emphasis"><em>after</em></span> | |
| matching the container pattern itself, i.e. we assume that all pattern variables are successfully bound to | |
| model elements (otherwise the pattern matching process should already fail). | |
| </p></td></tr></table></div><div class="highlights"><a name="def_CheckCondition_DefinedIn"></a><p><b>Defined In: </b> | |
| <a href="def_PatternBody.html" title="2.1.2. Pattern Body">pattern body</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_PatternVariableAssignment.html">Prev</a> </td><td align="center" width="20%"><a accesskey="u" href="sec_PatternDefinition.html">Up</a></td><td align="right" width="40%"> <a accesskey="n" href="def_ContainmentConstraint.html">Next</a></td></tr><tr><td valign="top" align="left" width="40%">2.1.7. Pattern Variable Assignment </td><td align="center" width="20%"><a accesskey="h" href="index.html">Home</a></td><td valign="top" align="right" width="40%"> 2.1.9. Containment Constraint</td></tr></table></div></body></html> |