- dev-luatex - Mailing Lists

A few newbie questions
by Yue Wang 01 Feb '09

01 Feb '09

Hi, Taco: Last week I stayed in my grandma's home (located in a beautiful countryside) which has limited internet access. So I planned to study the luatex source code during the stay. I read a small subsect of the LuaTeX source and most parts of MetaPost source code and have a few newbie questions: I will refer to the mp.w as an example, since it is finished and I am more familiar with the C programming language. - wouldn't it be great if we remove the packed data dependency? Knuth used packed data since memory space was very valuable during the years when he wrote the TeX and MetaFont program. By doing so, he can split a memory word (the space needed for a 32bit integer) into two, three or four so that he can save more spaces. In pdfTeX and MetaPost, almost all the important data structures (like all kinds of nodes, boxes, lists) are build on top of the packed data structure. For example, In TeX's char_node presentation, instead of using one word for font and one word for character, he can use one word to do so by defining two web macros font==type and character==subtype. However, Memory consumption is not that important these years and in LuaTeX other representations uses much more memory (like parsing a complicated opentype font and dumping it into a lua table using the fontforge library). So wouldn't it be bettter if we remove the packed data? It will make the code more readable at the cost of consuming a few more memory (the TeX web side is very memory efficient, so there won't be big memory footprint even if we double the memory consumption) since we can get rid of the messy web or C macros. For example, in Part 21, mp.w, we define more than a dozen macros to get all the variables of a edge which A points to its start. Such code may confuse modern programmers who learn to program in C after the mid-1990s. They prefer to do something like this: typedef fill_node struct { path *path_p; pen *pen_p; ..... int miterlim_var; }; if we want to create a new fill node, instead of creating its node, and setting its path_p to a given pointer p using mp_path_p(t)=p; it will be more understandable if we can do this: node * mp_new_fill_node (pointer, p){ fill_node *fn = malloc (sizeof (fill_node)); /* a fill_node*/ fn->path_p = p; fn->pen_p=NULL; fn->red_val=0 .... return fn } -Why can't we use IEEE floating number specification? TeX/MetaPost have it's own number presentation builtin. But this is a very complicated and strange floating number system which represent each number as a integer. I think IEEE floating number specification is good enough for implementing TeX? Today almost every operating system support float/double, and the precision is great. If we can do this, Part 7 of the mp.w and luatex.web can be totally removed, and we can also clean the conversion macros in the rest of the macros. If we remove the dependency of part 7 and part 9, maybe we can also make our code more portable on different machines. - Why should we do memory management ourselves? I can see that in mp.w, we maintain a node pool (a fixed continuous space in physical memory). When we want to allocate a node, we should call mp_get_node, which does several things like finding available place for memory allocation, reporting error if the memory is exceed then it tries to put everything with different structures into the pool. Wouldn't it be great if we just ask the operating system's C library to handle these tasks (like using malloc and free as the example code of mp_new_fill_node shows). Modern operating system's library is more efficient, and it will also make the luatex code looks better. - From the part of the code I read, if I understand correctly, the only reason of incorporating fontforge is to get the font Metrics data? If so, I think FreeType2 is sufficient to accomplish the task? [I think freetype2 is much smaller and efficient, and fontforge use freetype2] Yue Wang

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 31 Jan '09

31 Jan '09

------------------------------------------------------------------------ r1848 | oneiros | 2009-01-31 01:02:09 +0100 (Sat, 31 Jan 2009) | 2 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/ptexlib.h add missing declaration ------------------------------------------------------------------------ r1849 | oneiros | 2009-01-31 01:05:23 +0100 (Sat, 31 Jan 2009) | 2 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/ptexlib.h M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/tex/mlist.c M /trunk/src/texk/web2c/luatexdir/tex/texnodes.c indent ------------------------------------------------------------------------

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 30 Jan '09

30 Jan '09

------------------------------------------------------------------------ r1846 | taco | 2009-01-30 16:45:34 +0100 (Fri, 30 Jan 2009) | 4 lines Changed paths: M /trunk/manual/luatexref-t.tex M /trunk/src/texk/web2c/luatexdir/font/luafont.c M /trunk/src/texk/web2c/luatexdir/font/texfont.c M /trunk/src/texk/web2c/luatexdir/font/texfont.h M /trunk/src/texk/web2c/luatexdir/luatex.web M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/tex/mlist.c M /trunk/src/texk/web2c/luatexdir/texmath.h support a MathConstants table while loading fonts via lua, and make these settings have precedence over traditional tfm-style math parameters ------------------------------------------------------------------------ r1847 | taco | 2009-01-30 17:21:53 +0100 (Fri, 30 Jan 2009) | 2 lines Changed paths: M /trunk/manual/luatexref-t.pdf M /trunk/manual/luatexref-t.tex added a table listing default initializations of math parameters ------------------------------------------------------------------------

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 28 Jan '09

28 Jan '09

------------------------------------------------------------------------ r1844 | oneiros | 2009-01-28 16:30:04 +0100 (Wed, 28 Jan 2009) | 2 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/tex/math.c fix warning "passing argument 1 of ?\226?\128?\152tprint_esc?\226?\128?\153 discards qualifiers from pointer target type" ------------------------------------------------------------------------ r1845 | taco | 2009-01-28 16:41:16 +0100 (Wed, 28 Jan 2009) | 2 lines Changed paths: M /trunk/manual/luatexref-t.tex M /trunk/src/texk/web2c/luatexdir/luatex.defines M /trunk/src/texk/web2c/luatexdir/luatex.web M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/texmath.h improved names for the new math parameter primitives ------------------------------------------------------------------------

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 28 Jan '09

28 Jan '09

------------------------------------------------------------------------ r1843 | taco | 2009-01-28 15:05:32 +0100 (Wed, 28 Jan 2009) | 4 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/commands.h M /trunk/src/texk/web2c/luatexdir/lua/luatoken.c M /trunk/src/texk/web2c/luatexdir/luatex.defines M /trunk/src/texk/web2c/luatexdir/luatex.web M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/tex/mlist.c M /trunk/src/texk/web2c/luatexdir/texmath.h This introduces a whole batch of primitives for the setting of math parameters. The names are preliminary, and the settings are not used yet! ------------------------------------------------------------------------

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 28 Jan '09

28 Jan '09

------------------------------------------------------------------------ r1842 | taco | 2009-01-28 12:13:43 +0100 (Wed, 28 Jan 2009) | 3 lines Changed paths: M /trunk/manual/luatexref-t.tex M /trunk/src/texk/web2c/luatexdir/luatex.defines M /trunk/src/texk/web2c/luatexdir/luatex.web M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/tex/mlist.c M /trunk/src/texk/web2c/luatexdir/texmath.h Add four new primitives to support direct creation of cramped math styles ------------------------------------------------------------------------

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 27 Jan '09

27 Jan '09

------------------------------------------------------------------------ r1841 | taco | 2009-01-27 17:29:12 +0100 (Tue, 27 Jan 2009) | 3 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/tex/mlist.c M /trunk/src/texk/web2c/luatexdir/texmath.h extra math parameter acquisition to dedicated functions (this is a preliminary action needed for the coming MATH support) ------------------------------------------------------------------------

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Wrong placement of image nodes in non left-right directions
by Khaled Hosny 27 Jan '09

27 Jan '09

The image node placement code doesn't doesn't handle directional changes, which results in wrong placement of images in right-left (and other) directions, see the attached simple test suit (all images should fit into the frames). This patch attempts to fix this, but it does handle _LT/_LB and _RT/_RB only, as I can't test the others in PDF mode. Regards, -- Khaled

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 27 Jan '09

27 Jan '09

------------------------------------------------------------------------ r1840 | taco | 2009-01-27 09:34:49 +0100 (Tue, 27 Jan 2009) | 2 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/font/luafont.c print U+ strings instead of decimals in glyph consistency warnings ------------------------------------------------------------------------

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Cron <luatex@vz3> /var/www/luatex.org/www/bin/luatex-svn
by root＠www.metatex.org 26 Jan '09

26 Jan '09

------------------------------------------------------------------------ r1839 | taco | 2009-01-26 16:27:05 +0100 (Mon, 26 Jan 2009) | 3 lines Changed paths: M /trunk/src/texk/web2c/luatexdir/tex/math.c M /trunk/src/texk/web2c/luatexdir/tex/mlist.c remove some explicit maketexstring() calls, and a small cleanup in after_math() ------------------------------------------------------------------------

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