<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//en">

<!–Converted with LaTeX2HTML 2022 (Released January 1, 2022) –> <HTML lang="en"> <HEAD> <TITLE>Contents of So what are control symbols and words?</TITLE>

<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"> <META NAME="viewport" CONTENT="width=device-width, initial-scale=1.0"> <META NAME="Generator" CONTENT="LaTeX2HTML v2022">

<LINK REL="STYLESHEET" HREF="15527.css">

<LINK REL="next" HREF="node18_mn.html"> <LINK REL="previous" HREF="node16_mn.html"> <LINK REL="up" HREF="node12_mn.html"> <LINK REL="next" HREF="node18_mn.html"> </HEAD>

<BODY bgcolor="#ffffff" text="#000000" link="#9944EE" vlink="#0000ff" alink="#00ff00">

<H2><A ID="SECTION00445000000000000000"> So what are control symbols and words?</A> </H2><TT> In typing a document, we can think of ourselves as being in one of two distinct modes. We are either typing <EM>literal text</EM> (which will just be set into neat paragraphs for us) or we are typing text that will be <EM>interpreted</EM> by L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X as an instruction to insert a special symbol or to perform some action. Thus we are either typing material that will go straight into the document (with some beautification), or we are giving commands to L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X. </TT> <P> <TT>Some commands are implicit, in that we don't have to do anything much extra. For instance, we command L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X to end the present sentence by typing a period (that doesn't follow a capital letter). These are no so much commands as part of having to describe the logical structure of a document. </TT> <P> <TT>A <EM>control word</EM> is something of the form <code></code>, where the command name is a word made up only of the letters a to&nbsp;z and A to&nbsp;Z. A <EM>control symbol</EM> consists of a <TT>&#92;</TT> followed by single symbol that is not a letter. </TT> <P> <TT>Here are some examples: </TT> <UL> <LI>we have met the control space symbol <code> </code> before, </LI> <LI>the commands to set symbols like </LI> <LI><code></code> was a control symbol that told told L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X that the very next period did really end the sentence, </LI> <LI><code>LATEX</code> is a control word that tell L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X to insert its own name at the current point, </LI> <LI><code>&clubs#clubsuit;</code> instructs that a &#9827; be inserted, </LI> <LI><code>£</code> inserts a &#163; symbol, </LI> <LI><code>§</code> inserts a &#182; symbol, </LI> <LI><code></code> makes the ensuing text <EM>be emphasised</EM>, </LI> </UL> <P> <TT>These examples show that control sequences can be used to access symbols not available from the keyboard, do some typesetting tricks like setting the word L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X the way it does, and change the appearance of whole chunks of text as with <code></code>. We'll be meeting many more of these type of control sequences. </TT> <P> <TT>Another enormously powerful class of control sequences is those that accept <EM>arguments</EM>. They tell L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X to take the parts of text you supply and do something with them&mdash;like make a fraction by setting the first argument over the second and drawing a line of the appropriate length between them. These are part of what makes L<SUP><SMALL>A</SMALL></SUP>T<SMALL>E</SMALL>X so powerful, and here are some examples. </TT> <P> <UL> <LI><code>