The history of luaTEX 2006–2009 / v 0.50 - Pragma ADE

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The user interface is downward compatible: in MkIV the same top-level commands are provided as in MkII. However, the (previously required) conguration macros and ags are obsolete. This time, the conclusion is that the impact on ConTEXt is immense: The code for embedding graphics is very clean, and the running time for graphics inclusion is now negligible. Support for text in graphics is more natural now, and takes no runtime either (in MkII some parsing in TEX takes place, and if needed long lines are split; all this takes time). In the styles that Pragma ADE uses internally, there is support for the generation of placeholders for missing graphics. These placeholders are MetaPost graphics that have some 60 randomly scaled circles with randomized colors. The time involved in generating 50 such graphics is (on Hans' machine) some 14 seconds, while in LuaTEX only half a second is needed. Because LuaTEX needs more startup time and deals with larger fonts resources, pdfTEX is generally faster, but now that we have mplib, LuaTEX suddenly is the winner. 196 The MetaPost Library
XXIII The luaTEX Mix introduction The idea of embedding Lua into TEX originates in some experiments with Lua embedded in the SciTE editor. You can add functionality to this editor by loading Lua scripts. This is accomplished by a library that gives access to the internals of the editing component. The rst integration of Lua in pdfTEX was relatively simple: from TEX one could call out to Lua and from Lua one could print to TEX. My rst application was converting math encoded a calculator syntax to TEX. Following experiments dealt with MetaPost. At this point integration meant as little as: having some scripting language as addition to the macro language. But, even in this early stage further possibilities were explored, for instance in manipulating the nal output (i.e. the pdf code). The rst versions of what by then was already called LuaTEX provided access to some internals, like counter and dimension registers and the dimensions of boxes. Boosted by the oriental TEX project, the team started exploring more fundamental possibilities: hooks in the input/output, tokenization, fonts and nodelists. This was followed by opening up hyphenation, breaking lines into paragraphs and building ligatures. At that point we not only had access to some internals but also could inuence the way TEX operates. After that, an excursion was made to mplib, which fullled a long standing wish for a more natural integration of MetaPost into TEX. At that point we ended up with mixtures of TEX, Lua and MetaPost code. Medio 2008 we still need to open up more of TEX, like page building, math, alignments and the backend. Eventually LuaTEX will be nicely split up in components, rewritten in C, and we may even end up with Lua glueing together the components that make up the TEX engine. At that point the interoperation between TEX and Lua may be more rich that it is now. In the next sections I will discuss some of the ideas behind LuaTEX and the relationship between Lua and TEX and how it presents itself to users. I will not discuss the interface itself, which consists of quite some functions (organized in pseudo libraries) and the mechanisms used to access and replace internals (we call them callbacks). tex vs. lua TEX is a macro language. Everything boils down to either allowing stepwise expansion or explicitly preventing it. There are no real control features, like loops; tail recursion is a The luaTEX Mix 197
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MKII CONTEXT CONTEXT The history of
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XXI The luacation of TEX and ConTEX
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4 Introduction
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Keep in mind that the functionality
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tricky part of this conversion is t
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prologues := 1 ; mpprocset := 1 ; W
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code. However, the signicantly larg
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\input zip:///somezipfile.zip?name=
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ecause we could move all kind of po
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If an acrhive is not a real TEX tre
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luatools --generate This command wi
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I know that it sounds a bit messy,
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By combining Lua with TEX, we can d
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26 An example: CalcMath
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collapser was written. In the (pre)
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30 Going utf
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In practice we prefer a more abstra
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of making that table accessible for
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Therefore, it will be no surprise t
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{"special","pdf: 1 0 0 rg"}, {"font
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some neat feature of \TeX, once you
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OPENTYPE 144 17.571.732 ENC 268 782
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The font denition callback intercep
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When processing a not so large le b
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letter 105 i spacer 32 letter 116 t
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egister 2 3190 dimen other_char 50
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This example uses an active charact
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function tex.printlist(data) callba
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56 Token speak
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Interesting is that upto now I didn
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do end local function nextbyte(f) r
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\ctxlua{collectgarbage("setstepmul"
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Collecting tokens can take place in
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where TEX has to convert to and fro
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When experimenting with the new imp
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It will be clear that here we colle
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72 Nodes and attributes t={ attr={
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Let's end with an observation. Attr
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end end tex.sprint("\\setbox0=\\hbo
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78 Dirty tricks
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Those who read the previous chapter
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In a similar way support for xml wi
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Undoubtely this will have a huge im
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86 Going beta
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We like testing LuaTEX's open type
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k a el--rie am, ld p n th re, l ak
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his or her font). As said, it also
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["tag"]="calt", } }, ["name"]="ks_l
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When testing the implementation we
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Mr. rmn p Of course we have to test
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ه‎ مَ‏ ه‎ لِ‏ دْ‏
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لاۤئِهٰٖا لاۤئِه
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َ غْتَرِفٌُم عْتَر
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وَْر وةَ،‏ ٰ ي كَ‏
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white black t-green a=1.000 t=0.500
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Palets work with names: \definepale
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• support mechanism are under con
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So, effectively we set a box, and e
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116 Colors redone
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• Spaces at the end of the line (
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兡也包因沘氓侷柵苗
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〉 + 々 = 〉々〉々〉々
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124 Chinese, Japanese and Korean, a
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for k, v in pairs(_G) do print(k, v
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} [4] = 200 I mistakingly assumed t
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130 Optimization
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xetex metapost We can also
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\startluacode xml.sprint(xml.first(
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a[position()=5] maybe a[first()] ma
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Now we have: okay okay okay Repla
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\startxmlsetups xml:mysetups \xmlse
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c1d1 c2d2 d3 d4 d5 Here com
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c2 d3 b/c[1] c1 c2 a/c[1] d3 a/c[-1
Page 148 and 149: The code in traditional TEX that de
Page 150 and 151: and this is where MkIV hooks in ist
Page 152 and 153: con-text == [c][o](pre=n-,post=,rep
Page 154 and 155: luastate_bytes min:37009927, max:87
Page 156 and 157: dyn_used min:478158, max:554800, pa
Page 158 and 159: str_ptr min:2131299, max:2136226, p
Page 160 and 161: if_stack min:0, max:13, pages:326 k
Page 162 and 163: pdf_refximage min:0, max:7, pages:3
Page 164 and 165: 162 Collecting garbage
Page 166 and 167: \definefontfeature[coward] [kern=ye
Page 168 and 169: We do our tests of a variant of Con
Page 170 and 171: --make or --ini --run or --fmt= --l
Page 172 and 173: mtxrun --script font --list --patte
Page 174 and 175: Opening up TEX started with rewriti
Page 176 and 177: One can question if a properly work
Page 178 and 179: ound to fonts (instead of being com
Page 180 and 181: • TEX primitives Access to and co
Page 182 and 183: • Open an instance using mplib.ne
Page 184 and 185: is dened in the les whose names sta
Page 186 and 187: }, }, ["pen"]={ { ["left_x"]=2.4548
Page 188 and 189: local tx, ty = p.x_coord, p.y_coord
Page 190 and 191: \startreusableMPgraphic{test} fill
Page 192 and 193: vardef textext(expr str) = image (
Page 194 and 195: local factor = 65536*(7200/7227) fu
Page 196 and 197: end return t This is a typical exam
Page 200 and 201: key concept. There are few accessib
Page 202 and 203: \directlua 0 { for i=1,10 do tex.pr
Page 204 and 205: } end And still it's not okay, sinc
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Page 208 and 209: Of course we can discuss until eter
Page 210 and 211: some text some more When using Co
Page 212 and 213: and the document itself is processe
Page 214 and 215: setups and functions are assigned n
Page 216: using some kind of api and history
Page 226 and 227: In LuaTEX with ConTEXt MkIV support
Page 228 and 229: • Designers (or programmers) may
Page 230 and 231: 228 OpenType: too open?
Page 232 and 233: cannot be grabbed and they make the
Page 234 and 235: 232 It works!
Page 236 and 237: when writing the result to le, TEX
Page 238 and 239: 236 Virtual Reality
Page 240 and 241: \start \textdir TLT one \bidilro tw
Page 242 and 243: 240 Getting lost
Page 244 and 245: using a few arabic fonts, some chin
Page 246 and 247: The core data structure that we nee
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table can contain information about
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The ConTEXt cross reference mechani
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of them. Each lookup has a detailed
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otf.replacements otf.sequences otf.
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features: analyze=yes, calt=yes, cc
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feature mark, lookup ml_arab_l_16_s
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للِ‏ ه‎ ِ feature init, lo
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features: analyze=yes, calt=yes, cc
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esult: ۝ 1: [+TRT] U+6DD:۝ [-TRT]
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2: [+TRT] U+F01DD:۝ [-TRT] ۝ The
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Pro. Dr. Donld E. Knuth feature cal
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268 Tracking
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The order in which this happens now
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normalizers characters words fonts
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local function hyphenation(head,tai
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276 The order of things
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of LuaTEX Taco and I worked in para
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Next we see (scaled) Latin Modern:
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As you can see, it is possible to a
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next: U+FF008 { => U+FF06E { => U+F
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end } commands = { { "slot", 1, bas
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(a,b) = (1.20,3.40) So we don't nee
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} description = "SOLIDUS", directio
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⎧ ⎪ ⎪ ⎪ ⎨ ⎪ ⎪ ⎪ ⎩
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840 italic 60 top_accent (0,1020) f
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296 Unicode math
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tex.print("access") else tex.print(
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300 User code
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namespace with code not coming from
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• The code denes a few global tab
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ut this now refers to an index in a
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On the agenda is xing some ‘hyphe
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We also use the opportunity to slow
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Math. Because the TEX Gyre math pro
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Tracing on Taco's machine has shown
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node list callback tasks - 4 unique
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pdftex 1.28 (23) 2.07 (144) 6.96 (2
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July 19, 2009 - The number of files
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July 19, 2009 - The relative number
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The history of luaTEX 2006–2009 / v 0.50 - Pragma ADE

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