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<concept id="GUID-FE888721-C479-5D8A-810F-1A79575A1D58" xml:lang="en"><title>Introduction

to Lexical Analysis</title><shortdesc>A <codeph>TLex</codeph> object is used to perform lexical analysis. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>The class is used to:</p>

<ul>

<li id="GUID-4D79DE44-4E35-56C3-B6ED-5A82CD015FE9"><p>store a string</p> </li>

<li id="GUID-537012CB-CFCC-55C3-82DE-1D9B18539BEC"><p>maintain an extraction

mark to indicate the current lexical element being analysed</p> </li>

<li id="GUID-7B398A9C-42F1-5ABE-80ED-4237F72806BD"><p>maintain a pointer to

indicate the next character to be examined.</p> </li>

</ul>

<p>Member functions provide facilities to allow analysis and extraction of

lexical elements from a <codeph>TLex</codeph> object, and a variety of string-to-number

conversions.</p>

<p>The <codeph>TLex</codeph> class provides general-purpose lexical analysis

functions, using the locale-dependent functions of <codeph>TChar</codeph> to

identify whether characters are digits, letters etc. The data for these locale-dependent

functions is held in kernel-side locale tables. Thus, <codeph>TLex</codeph> functions

which use them, require an executive call. If an application requires very

fast lexical analysis of a language which is not locale-specific, then there

may be some advantage in designing and implementing a special-purpose lexical

analyzer class.</p>