EVOLUTION-MANAGER
Edit File: LanguageClasses.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Classes to Represent Unevaluated Language Objects</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for language-class {methods}"><tr><td>language-class {methods}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Classes to Represent Unevaluated Language Objects</h2> <h3>Description</h3> <p> The virtual class <code>"language"</code> and the specific classes that extend it represent unevaluated objects, as produced for example by the parser or by functions such as <code><a href="../../base/html/substitute.html">quote</a></code>. </p> <h3>Usage</h3> <pre> ### each of these classes corresponds to an unevaluated object ### in the S language. ### The class name can appear in method signatures, ### and in a few other contexts (such as some calls to as()). "(" "<-" "call" "for" "if" "repeat" "while" "name" "{" ### Each of the classes above extends the virtual class "language" </pre> <h3>Objects from the Class</h3> <p><code>"language"</code> is a virtual class; no objects may be created from it. </p> <p>Objects from the other classes can be generated by a call to <code>new(Class, ...)</code>, where <code>Class</code> is the quoted class name, and the ... arguments are either empty or a <em>single</em> object that is from this class (or an extension). </p> <h3>Methods</h3> <dl> <dt>coerce</dt><dd><p><code>signature(from = "ANY", to = "call")</code>. A method exists for <code>as(object, "call")</code>, calling <code>as.call()</code>. </p> </dd> </dl> <h3>Examples</h3> <pre> showClass("language") is( quote(sin(x)) ) # "call" "language" (ff <- new("if")) ; is(ff) # "if" "language" (ff <- new("for")) ; is(ff) # "for" "language" </pre> <hr /><div style="text-align: center;">[Package <em>methods</em> version 3.6.0 <a href="00Index.html">Index</a>]</div> </body></html>