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1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> 2<html> 3<head> 4<meta http-equiv="content-type" content="text/html;charset=iso-8859-1"> 5<title>Mom -- Definitions and Terms</title> 6</head> 7<body bgcolor="#dfdfdf"> 8 9<!====================================================================> 10 11<a href="using.html#TOP">Next</a> 12<a href="intro.html#TOP">Prev</a> 13<a href="toc.html">Back to Table of Contents</a> 14<p> 15<a name="TOP"></a> 16<a name="TERMS"> 17 <h1 align="center"><u>DEFINITIONS OF TERMS USED IN THIS MANUAL</u></h1> 18</a> 19 20<a href="#TERMS_TYPESETTING">Typesetting Terms</a> 21<br> 22<a href="#TERMS_GROFF">Groff Terms</a> 23<br> 24<a href="#TERMS_MOM">Mom Document Processing Terms</a> 25<p> 26I use a number of typesetting-specific and groff-specific terms 27throughout this documentation, as well as a few terms that apply 28to <strong>mom</strong> herself. To make life easier, I'll explain 29them here. Refer back to this section should you encounter a word 30or concept you're not familiar with. 31<p> 32<hr> 33 34<a name="TERMS_TYPESETTING"> 35 <h2><u>Typesetting terms</u></h2> 36</a> 37 38<ul> 39 <li><a href="#TERMS_ASCENDER">Ascender</a> 40 <li><a href="#TERMS_BASELINE">Baseline</a> 41 <li><a href="#TERMS_BALLOTBOX">Ballot box</a> 42 <li><a href="#TERMS_BULLET">Bullet</a> 43 <li><a href="#TERMS_CAPHEIGHT">Cap-height</a> 44 <li><a href="#TERMS_DESCENDER">Descender</a> 45 <li><a href="#TERMS_DISCRETIONARYHYPHEN">Discretionary hyphen</a> 46 <li><a href="#TERMS_DROPCAP">Drop cap</a> 47 <li><a href="#TERMS_EM">Em/en</a> 48 <li><a href="#TERMS_FAMILY">Family</a> 49 <li><a href="#TERMS_FIGURESPACE">Figure space/Digit space</a> 50 <li><a href="#TERMS_FIXEDWIDTHSPACE">Fixed width space</a> 51 <li><a href="#TERMS_FONT">Font</a> 52 <li><a href="#TERMS_FORCE">Force justify</a> 53 <li><a href="#TERMS_JUST">Justify/justification</a> 54 <li><a href="#TERMS_GUTTER">Gutter</a> 55 <li><a href="#TERMS_KERN">Kerning</a> 56 <li><a href="#TERMS_KERNUNIT">Kern Units</a> 57 <li><a href="#TERMS_LEADING">Lead/leading</a> 58 <li><a href="#TERMS_LEADER">Leaders</a> 59 <li><a href="#TERMS_LIGATURES">Ligature</a> 60 <li><a href="#TERMS_PICASPOINTS">Picas/Points</a> 61 <li><a href="#TERMS_PS">Point Size</a> 62 <li><a href="#TERMS_QUAD">Quad</a> 63 <li><a href="#TERMS_RAG">Rag</a> 64 <li><a href="#TERMS_SHAPE">Shape</a> 65 <li><a href="#TERMS_SOLID">Solid/set solid</a> 66 <li><a href="#TERMS_TRACKKERNING">Track kerning/Line kerning</a> 67 <li><a href="#TERMS_UNBREAKABLESPACE">Unbreakable space</a> 68 <li><a href="#TERMS_WEIGHT">Weight</a> 69 <li><a href="#TERMS_WORDSPACE">Word space</a> 70 <li><a href="#TERMS_XHEIGHT">x-height</a> 71</ul> 72 73<dl> 74<dt><a name="TERMS_ASCENDER"><em>Ascender</em></a> 75<dd>The portion of a letter that extends above the bowl. For example, 76the letters a, c, and e have no ascenders. The letters b, d, and h 77do. 78 79<dt><a name="TERMS_BASELINE"><em>Baseline</em></a> 80<dd>The imaginary line on which the bottoms of capital letters and the 81bowls of lower case letters rest. 82 83<dt><a name="TERMS_BALLOTBOX"><em>Ballot box</em></a> 84<dd>An unfilled square, usually 85<a href="#TERMS_CAPHEIGHT">cap-height</a> 86in size, typically placed beside items in a checklist. 87 88<dt><a name="TERMS_BULLET"><em>Bullet</em></a> 89<dd>A small, filled circle typically found beside items or points in 90a list. 91 92<dt><a name="TERMS_CAPHEIGHT"><em>Cap-height</em></a> 93<dd>The height of the tallest capital letter in a given 94<a href="#TERMS_FONT">font</a> 95at the current 96<a href="#TERMS_PS">point size</a>. 97 98<dt><a name="TERMS_DESCENDER"><em>Descender</em></a> 99<dd>The portion of a letter that extends beneath the 100<a href="#TERMS_BASELINE">baseline</a> 101(j, q, y are letters with descenders). 102 103<dt><a name="TERMS_DISCRETIONARYHYPHEN"><em>Discretionary hyphen</em></a> 104<dd>A symbol inserted between two syllables of a word that indicates to a 105typesetting program the legal hyphenation points in the word. Normally, 106if hyphenation is turned on, groff knows where to hyphenate words. 107However, hyphenation being what it is (in English, at any rate), 108groff doesn't always get it right. Discretionary hyphens make sure 109it does. In the event that the word doesn't need to be hyphenated 110at all, groff leaves them alone. In groff, the discretionary hyphen is 111entered with 112<p> 113<pre> 114 \% 115</pre> 116 117(backslash followed by a percent). 118 119<dt><a name="TERMS_DROPCAP"><em>Drop cap</em></a> 120<dd>A large, usually upper-case letter that introduces the first 121paragraph of a document or section thereof. The top of the drop 122cap usually lines up with the top of the first line of the 123paragraph, and typically "drops" several lines lower. 124Text adjacent to the drop cap is indented to the right of the 125letter until the bottom of the drop cap is reached, at which 126point text reverts to the left margin. 127 128<dt><a name="TERMS_EM"><em>Em/en</em></a> 129<dd>An em is a relative measurement equal to the width of the 130letter M at a given 131<a href="#TERMS_PS">point size</a> 132in a given 133<a href="#TERMS_FONT">font</a>. 134Since most Ms are designed square, an em is usually (but sometimes 135erroneously) considered to be the same size as the current point 136size (i.e. if the point size of the type is 12, one em equals 12 137points). An en is equal to the width of a letter N (historically 1382/3 of an em, although groff treats an en as 1/2 of an em). 139Typically, ems and ens are used to measure indents, or to define the 140length of dashes (long hyphens). 141 142<dt><a name="TERMS_FAMILY"><em>Family</em></a> 143<dd>The collective name by which a collection of 144<a href="#TERMS_FONT">fonts</a> 145are known, e.g. Helvetica, Times Roman, Garamond. 146 147<dt><a name="TERMS_FIGURESPACE"><em>Figure space/Digit space</em></a> 148<dd>A 149<a href="#TERMS_FIXEDWIDTHSPACE">fixed width space</a> 150that has the width of one digit. Used for aligning numerals in, 151say, columns or numbered lists. In groff, the figure space is 152entered with 153<p> 154<pre> 155 \0 156</pre> 157 158(backslash followed by a zero). 159 160<dt><a name="TERMS_FIXEDWIDTHSPACE"><em>Fixed width space</em></a> 161<dd>Equal to 162<a href="#TERMS_WORDSPACE">word space</a>, 163but does not expand or contract when text is 164<a href="#TERMS_JUST">justified</a>. 165In groff, fixed width space is entered with 166<p> 167<pre> 168 \<space> 169</pre> 170 171where <space> means "hit the spacebar on your keyboard." 172 173<dt><a name="TERMS_FONT"><em>Font</em></a> 174<dd>The specific 175<a href="#TERMS_WEIGHT">weight</a> 176and 177<a href="#TERMS_SHAPE">shape</a> 178of type within a 179<a href="#TERMS_FAMILY">family</a>, 180e.g. light, medium, bold (which are weights), and roman, italic, 181condensed (which are shapes). By default, groff knows of four fonts 182within its default set of families: R (medium roman), I (medium 183italic), B (bold roman) and BI (bold italic). 184 185<dt><a name="TERMS_FORCE"><em>Force justify 186</em></a> 187<dd>Sometimes, in 188<a href="#TERMS_JUST">justified</a> 189text, a line needs to be broken short of the right margin. Force 190justifying means telling a typesetting program (like groff) that you 191want the line broken early AND that you want the line's word spacing 192stretched to force the line flush with the right margin. 193 194<dt><a name="TERMS_GUTTER"><em>Gutter</em></a> 195<dd>The vertical whitespace separating columns of type. 196 197<dt><a name="TERMS_JUST"><em>Justify/justification</em></a> 198<dd>Lines of type are justified when they're flush at both the left and 199right margins. Justification is the act of making both margins flush. 200Some people use the terms "left justified" and "right justified" 201to mean type where only the left (or right) margins align. I don't. 202See 203<a href="#TERMS_QUAD">quad</a>. 204 205<dt><a name="TERMS_KERN"><em>Kerning</em></a> 206<dd>Moving pairs of letters closer together to remove excess 207whitespace between them. In the days before phototypesetting, 208type was set from small, rectangular blocks of wood or metal, each 209block having exactly one letter. Because the edge of each block 210determined the edge of each letter, certain letter combinations (TA, 211for example) didn't fit together well and had to be mortised by hand 212to bring them visually closer. Modern typesetting systems usually 213take care of kerning automatically, but they're far from perfect. 214Professional typesetters still devote a lot of time to fitting letters 215and punctuation together properly. 216 217<dt><a name="TERMS_KERNUNIT"><em>Kern Units</em></a> 218<dd>A relative distance equal to 1/36 of the current 219<a href="#TERMS_PS">point size</a>. 220Used between individual letters 221for 222<a href="#TERMS_KERN">kerning</a>. 223Different typesetting systems use different values (1/54 is 224popular), and sometimes call kern units by a different name. 225<p> 226<strong>Experts: 227<br></strong>A kern unit has nothing to do with groff 228machine units. 229 230<dt><a name="TERMS_LEADING"><em>Lead/leading</em></a> 231<dd>The distance from the 232<a href="#TERMS_BASELINE">baseline</a> 233of one line of type to the line of type immediately beneath it. 234Pronounced "ledding." Also called line spacing. Usually measured 235in 236<a href="#TERMS_PICASPOINTS">points</a>. 237<p> 238<em>In case you're interested...</em> In previous centuries, 239lines of type were separated by thin strips of--you guessed 240it--lead. Lines of type that had no lead between them were said to 241be "set solid." Once you began separating them with strips 242of lead, they were said to be "leaded", and the spacing was 243expressed in terms of the number of 244<a href="#TERMS_PICASPOINTS">points</a> 245of lead. For this reason, "leading" and "line 246spacing" aren't, historically speaking, synonymous. If type 247was set 10 on 12, for example, the leading was 2 points, not 12. 248Nowadays, however, the two terms are used interchangeably to mean 249the distance from baseline to baseline. 250 251<dt><a name="TERMS_LEADER"><em>Leaders</em></a> 252<dd>Single characters used to fill lines, usually to their end. 253So called because they "lead" the eye from one element 254of the page to another. For example, in the following (brief) 255Table of Contents, the periods (dots) are leaders. 256<p> 257<pre> 258 Foreword............... 2 259 Chapter 1.............. 5 260 Chapter 2.............. 38 261 Chapter 3.............. 60 262</pre> 263 264<dt><a name="TERMS_LIGATURES"><em>Ligature</em></a> 265<dd>Ligatures are letters joined together to form a single character. 266The commonest are fi, fl, ff, ffi and ffl. Others are ae and oe. 267Occasionally, one sees an st ligature, but this is archaic and 268quite rare. 269 270<dt><a name="TERMS_PICASPOINTS"><em>Picas/Points</em></a> 271<dd>There are twelve points in a pica, and six picas in an inch 272(hence 72 points to the inch). In the same way that gem-dealers 273have always used their own system of measurement for weight (carats), 274typographers have always used their own system of measurement for type. 275 276<dt><a name="TERMS_PS"><em>Point Size</em></a> 277<dd>The nominal size of type, measured in 278<a href="#TERMS_PICASPOINTS">points</a> 279from the bottom of the longest 280<a href="#TERMS_DESCENDER">descender</a> 281to the top of the highest 282<a href="#TERMS_ASCENDER">ascender</a>. 283In reality, type is always fractionally smaller than its point size. 284 285<dt><a name="TERMS_QUAD"><em>Quad</em></a> 286<dd>When only one margin of type is flush, lines of type are quadded in 287the direction of the flush margin. Therefore, quad left means the 288left margin is flush, the right isn't. Quad right means the right 289margin is flush, the left isn't. Quad centre means neither the left 290nor the right margin is flush; rather, lines of type are quadded on 291both sides so that type appears centred on the page. 292 293<dt><a name="TERMS_RAG"><em>Rag</em></a> 294<dd>Describes a margin that isn't flush. Rag right means the right 295margin isn't flush. Rag left means the left margin isn't flush. 296The expression "flush left/rag right" is sometimes used to describe 297type that is 298<a href="#TERMS_QUAD">quadded</a> 299left. 300 301<dt><a name="TERMS_SHAPE"><em>Shape</em></a> 302<dd>The degree of slant and/or the width of characters. 303(Technically speaking, this is not a proper typesetting term; 304however, it may help clarify some concepts presented in these 305documents.) 306<p> 307Some typical shapes are: 308<ul> 309 <li>"Roman", which has no slant, and has letterforms of 310 average width 311 <li>"Italic", which is slanted, and has letterforms 312 of average width 313 <li>"Condensed", which has no slant, but has 314 letterforms narrower than the average represented by Roman 315 <li>"Condensed Italic", which is slanted, with letterforms narrower 316 than average 317</ul> 318The term 319<a href="#TERMS_FONT">font</a>, 320as it is used in these documents, refers to a combination of 321<a href="#TERMS_WEIGHT">weight</a> 322and shape. 323 324<dt><a name="TERMS_SOLID"><em>Solid/set solid</em></a> 325<dd>When no 326<a href="#TERMS_LEADING">lead</a> 327is added between lines of type (i.e. the 328<a href="#TERMS_PS">point size</a> 329and linespacing are the same), the lines are said to be "set 330solid." 331 332<dt><a name="TERMS_TRACKKERNING"><em>Track kerning/Line kerning</em></a> 333<dd>Sometimes, it's advantageous to increase or decrease the amount of 334space between every letter in a line by an equal (usually small) 335amount, in order to fit more (or fewer) characters on the line. 336The correct term is letter spacing, but track kerning and line kerning 337(and sometimes, just "kerning") have come to mean the same thing. 338 339<dt><a name="TERMS_UNBREAKABLESPACE"><em>Unbreakable space</em></a> 340<dd>Equal to 341<a href="#TERMS_WORDSPACE">word space</a>, 342however words separated by an unbreakable space will always be kept 343together on the same line. Expands and contracts like word space. 344Useful for proper names, which one should, whenever possible, avoid 345splitting onto two lines. In groff, unbreakable space is entered 346with 347<p> 348<pre> 349 \~ 350</pre> 351 352(backslash followed by a tilde). 353 354<dt><a name="TERMS_WEIGHT"><em>Weight</em></a> 355<dd>The thickness of the strokes of letterforms. Medium and Book 356have average thicknesses and are the weights used for most of the 357text in books, magazines, newspapers, etc. Light has strokes 358slightly thinner than Medium or Book, but is still acceptable for 359most text. Semibold, Bold, Heavy and Black all have strokes of 360increasing thickness, making them suitable for heads, subheads, 361headlines and the like. 362 363<dt><a name="TERMS_WORDSPACE"><em>Word space</em></a> 364<dd>The amount of whitespace between words. When text is 365<a href="#TERMS_JUST">justified</a>, 366word space expands or contracts to make the margins flush. 367 368<dt><a name="TERMS_XHEIGHT"><em>x-height</em></a> 369<dd>The height of a lower case letter x in a given font at a given 370point size. Generally used to mean the average height of the bowl 371of lower case letters. 372</dl> 373<p> 374<hr> 375 376<a name="TERMS_GROFF"> 377 <h2><u>Groff terms</u></h2> 378</a> 379 380<ul> 381 <li><a href="#TERMS_ALIAS">Alias</a> 382 <li><a href="#TERMS_ARGUMENTS">Arguments</a> 383 <li><a href="#TERMS_COMMENTLINES">Comment lines</a> 384 <li><a href="#TERMS_CONTROLLINES">Control Lines</a> 385 <li><a href="#TERMS_FILLED">Filled lines</a> 386 <li><a href="#TERMS_INLINES">Inline escapes</a> 387 <li><a href="#TERMS_INPUTLINE">Input line</a> 388 <li><a href="#TERMS_MACROS">Macros</a> 389 <li><a href="#TERMS_UNITS">Machine units</a> 390 <li><a href="#TERMS_NUMERICARGUMENT">Numeric argument</a> 391 <li><a href="#TERMS_OUTPUTLINE">Output line</a> 392 <li><a href="#TERMS_PRIMITIVES">Primitives</a> 393 <li><a href="#TERMS_STRINGARGUMENT">String Argument</a> 394 <li><a href="#TERMS_UNITOFMEASURE">Unit of measure</a> 395 <li><a href="#TERMS_ZEROWIDTHCHARACTER">Zero-width character</a> 396</ul> 397<dl> 398 399<dt><a name="TERMS_ALIAS"><em>Alias</em></a> 400<dd>A 401<a href="#TERMS_MACROS">macro</a> 402invoked by a name different from its "official" 403name. For example, the official name of the macro to change 404<a href="#TERMS_FAMILY">family</a> 405is <strong>FAMILY</strong>. Its alias is 406<strong>FAM</strong>. Aliases may be created for any macro (via the 407<a href="goodies.html#ALIAS">ALIAS</a> 408macro) provided the alias uses a name not already taken 409by the <strong>mom</strong> macros or one of the groff 410<a href="#TERMS_PRIMITIVES">primitives</a>. 411For a complete list of words or names you must not use, see the 412<a href="reserved.html#RESERVED">list of reserved words</a>. 413 414<dt><a name="TERMS_ARGUMENTS"><em>Arguments</em></a> 415<dd>Parameters or information needed by a 416<a href="#TERMS_MACROS">macro</a> 417to do its job. For example, in the macro 418<p> 419<pre> 420 .PT_SIZE 12 421</pre> 422 423"12" is the argument. In the macro 424<p> 425<pre> 426 .QUAD LEFT 427</pre> 428 429LEFT is the argument. Arguments are separated from macros by spaces. 430Some macros require several arguments; each is separated by a space. 431 432<dt><a name="TERMS_COMMENTLINES"><em>Comment Lines</em></a> 433<dd><a href="#TERMS_INPUTLINE">Input lines</a> 434introduced with the comment character 435<p> 436<pre> 437 \# 438</pre> 439 440When processing output, groff silently ignores everything on a 441line that begins with the comment character. 442 443<dt><a name="TERMS_CONTROLLINES"><em>Control Lines</em></a> 444<dd>Instructions to groff that appear on a line by themselves, 445which means that "control lines" are either 446<a href="#TERMS_MACROS">macros</a> 447or groff 448<a href="#TERMS_PRIMITIVES">primitives</a>. 449Control lines begin with a period or, occasionally, an apostrophe. 450 451<dt><a name="TERMS_FILLED"><em>Filled lines/fill mode</em></a> 452<dd>Automatic 453<a href="#TERMS_JUST">justification</a> 454or 455<a href="#TERMS_QUAD">quadding</a>. 456In fill mode, the ends of lines as they appear in your text editor 457are ignored. Instead, words from adjoining 458<a href="#TERMS_INPUTLINE">input lines</a> 459are added one at a time to the output line until no more words fit. 460Then, depending whether text is to be 461<a href="#TERMS_JUST">justified</a> 462or 463<a href="#TERMS_QUAD">quadded</a> 464(left, right, or centre), and depending on whether automatic 465hyphenation is turned on, groff attempts to hyphenate the last word, 466or, barring that, spreads and breaks the line (when justification 467is turned on) or breaks and quads the line (when quadding is turned 468on). 469<p> 470<a name="TERMS_NOFILL"></a> 471Nofill mode (non-filled text) means that groff respects the ends 472of lines as they appear in your text editor. 473 474<dt><a name="TERMS_INLINES"><em>Inline escapes</em></a> 475<dd>Instructions issued to groff that appear as part of an 476<a href="#TERMS_INPUTLINE">input line</a> 477(as opposed to 478<a href="#TERMS_MACROS">macros</a>, 479which must appear on a line by themselves). Inline escapes are 480always introduced by the backslash character. For example, 481<p> 482<pre> 483 A line of text with the word T\*[BU 2]oronto in it 484</pre> 485 486contains the inline escape \*[BU 2] (which means "move the letter 487'o' 2 488<a href="#TERMS_KERNUNIT">kern units</a> 489closer to the letter 'T'"). 490<p> 491<strong>Mom</strong>'s inline escapes always take the form 492<strong>\*[</strong><i>ESCAPE</i><strong>]</strong>, where <i>ESCAPE</i> 493is composed of capital letters, sometimes followed immediately 494by a digit, sometimes followed by a space and a 495<a href="#TERMS_NUMERICARGUMENT">numeric argument</a>. 496<strong>Groff</strong>'s escapes begin with the backslash character 497but typically have no star and are in lower case. For example, the 498<strong>mom</strong> escapes to move forward 6 points on a line are 499either 500<p> 501<pre> 502 \*[FP6] or \*[FWD 6p] 503</pre> 504 505while the <strong>groff</strong> escape for the same thing is 506<p> 507<pre> 508 \h'6p' 509</pre> 510 511<dt><a name="TERMS_INPUTLINE"><em>Input line</em></a> 512<dd>A line of text as it appears in your text editor. 513 514<dt><a name="TERMS_MACROS"><em>Macros</em></a> 515<dd>Instructions embedded in a document that determine how groff processes 516the text for output. <strong>mom</strong>'s macros always begin with a 517period, on a line by themselves, and must be typed in capital letters. 518Typically, macros contain complex commands issued to groff--behind 519the scenes--via groff 520<a href="#TERMS_PRIMITIVES">primitives</a>. 521 522<dt><a name="TERMS_UNITS"><em>Machine units</em></a> 523<dd>A machine unit is 1/1000 of a 524<a href="#TERMS_PICASPOINTS">point</a> 525when the groff device is ps. ("ps" means 526"PostScript"--the default device for which groff 527prepares output, and the device for which <strong>mom</strong> was 528specifically designed.) 529 530<dt><a name="TERMS_NUMERICARGUMENT"><em>Numeric argument</em></a> 531<dd>An 532<a href="#TERMS_ARGUMENT">argument</a> 533that has the form of a digit. Numeric arguments can be built out 534of arithmetic expressions using +, -, *, and / for plus, minus, 535times, and divided-by respectively. If a numeric argument requires 536a 537<a href="#TERMS_UNITOFMEASURE">unit of measure</a>, 538a unit of measure must be appended to <em>every</em> digit in the 539argument. For example: 540<p> 541<pre> 542 .ALD 1i-1v 543</pre> 544 545<strong>NOTE:</strong> groff does not respect the order of operations, 546but rather evaluates arithmetic expressions from left to right. 547Parentheses must be used to circumvent this peculiarity. Not to 548worry, though. The likelihood of more than just the occasional plus 549or minus sign when using <strong>mom</strong>'s macros is slim. 550 551<dt><a name="TERMS_OUTPUTLINE"><em>Output line</em></a> 552<dd>A line of text as it appears in output copy. 553 554<dt><a name="TERMS_PRIMITIVES"><em>Primitives</em></a> 555<dd>The two-letter, lower case instructions groff uses as its 556native command language, and out of which macros are built. 557 558<dt><a name="TERMS_STRINGARGUMENT"><em>String Argument</em></a> 559<dd>Technically, any 560<a href="#TERMS_ARGUMENTS">argument</a> 561that is not numeric. In this documentation, string argument means 562an argument that requires the user to input text. For example, in 563the 564<a href="#TERMS_MACROS">macro</a> 565<p> 566<pre> 567 .TITLE "My Pulitzer Novel" 568</pre> 569 570"My Pulitzer Novel" is a string argument. 571<p> 572Because string arguments must be enclosed by double-quotes, you can't 573use double-quotes as part of the string argument. If you need 574double-quotes to be part of a string argument, use the 575<a href="#TERMS_INLINES">inline escapes</a> 576<strong>\(lq</strong> and <strong>\(rq</strong> (leftquote and rightquote 577respectively) in place of the double-quote character ("). 578 579<dt><a name="TERMS_UNITOFMEASURE"><em>Unit of measure</em></a> 580<dd>The single letter after a 581<a href="#TERMS_NUMERICARGUMENT">numeric argument</a> 582that tells <strong>mom</strong> what measurement scale the argument 583should use. Common valid units are: 584<p> 585<table valign="baseline" summary="unitsofmeasure"> 586<tr><td><strong>i</strong><td> = <td>inches 587<tr><td><strong>p</strong><td> = <td>points 588<tr><td><strong>P</strong><td> = <td>picas 589<tr><td><strong>c</strong><td> = <td>centimetres 590<tr><td><strong>m</strong><td> = <td>ems 591<tr><td><strong>n</strong><td> = <td>ens 592<tr><td><strong>v</strong><td> = <td>the current leading (line space)</td></tr> 593</table> 594<br> 595<dd>Units of measure must come immediately after the numeric argument (i.e. 596with no space between the argument and the unit of measure), like this: 597<p> 598<pre> 599 .ALD 2v 600 .LL 39P 601 .IL 1i 602</pre> 603 604The above example advances 2 line spaces and sets the line length to 60539 picas with a left indent of 1 inch. 606<p> 607<strong>IMPORTANT:</strong> Most <strong>mom</strong> macros 608that set the size or measure of something MUST be given a unit of 609measure. <strong>mom</strong>'s macros do not have default units 610of measure. There are a couple of exceptions, the most notable of 611which are <strong>PT_SIZE</strong> and <strong>LS</strong>. Both use 612<a href="#TERMS_PICASPOINTS">points</a> 613as the default unit of measure, which means 614you don't have to append "p" to their argument. 615<p> 616You can enter decimal values for any unit of measure. Different units 617may be combined by adding them together (e.g. 1.5i+2m, which gives a 618measure of 1-1/2 inches plus 2 ems). 619<p> 620<strong>NOTE:</strong> a pica is composed of 12 points, 621therefore 12.5 picas is 12 picas and 6 points, not 12 picas 622and 5 points. If you want 12 picas and 5 points, you have to 623enter the measure as 12P+5p. 624 625<dt><a name="TERMS_ZEROWIDTHCHARACTER"><em>Zero-width character</em></a> 626<dd>The 627<a href="#TERMS_INLINES">inline escape</a> 628that allows you to print a literal period, apostrophe and, if 629<a href="#TERMS_OUTPUTLINE">output lines</a> 630are 631<a href="#TERMS_FILLED">filled</a>, 632a space that falls at the beginning of an 633<a href="#TERMS_INPUTLINE">input line</a>. 634It looks like this: 635<p> 636<pre> 637 \& 638</pre> 639 640(backslash followed by an ampersand). 641<p> 642Normally, groff interprets a period (or an apostrophe) at the beginning 643of an input line as meaning that what follows is a 644<a href="#TERMS_CONTROLLINES">control line</a>. 645In fill modes, groff treats a space at the beginning of an input 646line as meaning "start a new line and put a space at the 647beginning of it." If you want groff to interpret periods and 648apostrophes at the beginning of input lines literally (i.e. print 649them), or spaces at the beginning of input lines as just garden 650variety word spaces, you must start the line with the zero-width 651character. 652</dl> 653<p> 654<hr> 655 656<a name="TERMS_MOM"> 657 <h2><u>Mom's Document Processing Terms</u></h2> 658</a> 659 660<ul> 661 <li><a href="#TERMS_BLOCKQUOTE">Blockquote</a> 662 <li><a href="#TERMS_CONTROLMACRO">Control macro</a> 663 <li><a href="#TERMS_DOCHEADER">Docheader</a> 664 <li><a href="#TERMS_EPIGRAPH">Epigraph</a> 665 <li><a href="#TERMS_FOOTER">Footer</a> 666 <li><a href="#TERMS_HEAD">Head</a> 667 <li><a href="#TERMS_HEADER">Header</a> 668 <li><a href="#TERMS_LINEBREAK">Linebreak</a> 669 <li><a href="#TERMS_PARAHEAD">Paragraph head</a> 670 <li><a href="#TERMS_QUOTE">Quote</a> 671 <li><a href="#TERMS_RUNNING">Running text</a> 672 <li><a href="#TERMS_SUBHEAD">Subhead</a> 673 <li><a href="#TERMS_TOGGLE">Toggle</a> 674</ul> 675<dl> 676<dt><a name="TERMS_BLOCKQUOTE"><em>Blockquote</em></a> 677<dd>Cited material other than 678<a href="#TERMS_QUOTE">quotes</a>. 679Typically set at a smaller point size than paragraph text, indented 680from the left and right margins. Blockquotes are 681<a href="#TERMS_FILLED">filled</a>. 682 683<dt><a name="TERMS_CONTROLMACRO"><em>Control macro</em></a> 684<dd>Macros used in 685<a href="docprocessing.html#DOCPROCESSING">document processing</a> 686to control/alter the appearance of document elements (e.g. heads, 687quotes, footnotes, 688<a href="#TERMS_HEADER">headers</a>, 689etc.). 690 691<dt><a name="TERMS_DOCHEADER"><em>Document header/docheader</em></a> 692<dd>Document information (title, subtitle, author, etc) output 693at the top of page one. 694 695<dt><a name="TERMS_EPIGRAPH"><em>Epigraph</em></a> 696<dd>A short, usually cited passage that appears at the 697beginning of a chapter, story, or other document. 698 699<dt><a name="TERMS_FOOTER"><em>Footer/page footer</em></a> 700<dd>Document information (frequently author and title) output in 701the bottom margin of pages <em>after</em> page one. Not to be 702confused with footnotes, which are considered part of 703<a href="#TERMS_RUNNING">running text</a>. 704 705<dt><a name="TERMS_HEAD"><em>Head</em></a> 706<dd>A title that introduces a major section of a document. 707 708<dt><a name="TERMS_HEADER"><em>Header/page header</em></a> 709<dd>Document information (frequently author and title) output in 710the top margin of pages <em>after</em> page one. 711<p> 712<strong>NOTE:</strong> In terms of content and style, headers and 713<a href="#TERMS_FOOTER">footers</a> 714are the same; they differ only in their placement on the page. In 715most places in this documentation, references to the content or 716style of headers applies equally to footers. 717 718<dt><a name="TERMS_LINEBREAK"><em>Linebreak/author linebreak</em></a> 719<dd>A horizontal gap in 720<a href="#TERMS_RUNNING">running text</a>, 721frequently set off by typographic symbols such as asterisks or 722daggers. Used to indicate a shift in the content of a document 723(e.g. a scene change in a short story). Also commonly called a 724scene break or a section break. 725 726<dt><a name="TERMS_PARAHEAD"><em>Paragraph head</em></a> 727<dd>A title joined to the body of a paragraph; hierarchically one 728level beneath 729<a href="#TERMS_SUBHEAD">subheads</a>. 730 731<dt><a name="TERMS_QUOTE"><em>Quote</em></a> 732<dd>A quote, to <strong>mom</strong>, is a line-for-line setting 733of quoted material (e.g. poetry, song lyrics, or a snippet of 734programming code). You don't have to use 735<a href="typesetting.html#BR">BR</a> 736with quotes. 737 738<dt><a name="TERMS_RUNNING"><em>Running text</em></a> 739<dd>In a document formatted with <strong>mom</strong>, running 740text means text that forms the body of the document, including 741elements such as heads and subheads. 742<a href="#TERMS_DOCHEADER">Docheaders</a>, 743<a href="#TERMS_HEADER">headers</a>, 744<a href="#TERMS_FOOTER">footers</a> 745and page numbers are NOT part of running text. 746 747<dt><a name="TERMS_SUBHEAD"><em>Subhead</em></a> 748<dd>A title used to introduce secondary sections of a document; 749hierarchically one level beneath sections introduced by 750<a href="#TERMS_HEAD">heads</a>. 751 752<dt><a name="TERMS_TOGGLE"><em>Toggle</em></a> 753<dd>A macro or tag that, when invoked without an argument, 754begins something or turns a feature on, and, when invoked with 755ANY argument, ends something or turns a feature off. See 756<a href="intro.html#TOGGLE_EXAMPLE">Example 3</a> 757of the section 758<a href="intro.html#MACRO_ARGS">How to read macro arguments</a>. 759</dl> 760 761<p> 762<hr> 763<a href="using.html#TOP">Next</a> 764<a href="intro.html#TOP">Prev</a> 765<a href="#TOP">Top</a> 766<a href="toc.html">Back to Table of Contents</a> 767</body> 768</html>