Is it possible to see the output of the TeX ‘pre-processor’, i. e. the intermediate step before the actual output is done but with all user-defined macros replaced and only a subset of TeX primitives left?
Or is there no such intermediate step?
Write
\edef\xxx{Any text with any commands. For example, $\phantom x$.}
And then for output in the log-file
\show\xxx
or for output in your document
\meaning\xxx
There is no "pre-processor" in TeX. The replacement text for any control sequence at any stage can vary (this is used for a lot of things!). For example
\def\demo{\def\demo{cde}}
\demo
will first define \demo in one way and then change it. In the same way, you can redirect TeX primitives. For example, the LaTeX kernel moves \input to an internal position and alters it. A simplified version:
\let\##input\input
\def\input#1{\##input#1 }
Try the Selective Macro Expander.
TeX has a lot of difference tracing tools built in, including tracing macro expansion. This only traces live macros as they are actually expanded, but it's still quite useful. Full details in The TeXbook and probably elsewhere.
When I'm trying to debug a macro problem I generally just use the big hammer:
\tracingall\tracingonline
then I dig in the output or the .log file for what I want to know.
There's a lot of discussion of this issue on this question at tex.SE, and this question. But I'll take the opportunity to note that the best answer (IMO) is to use the de-macro program, which is a python script that comes with TeXLive. It's quite capable, and can handle arguments as well as simple replacements.
To use it, you move the macros that you want expanded into a <something>-private.sty file, and include it into your document with \usepackage{<something>-private}, then run de-macro <mydocument>. It spits out <mydocument>-clean.tex, which is the same as your original, but with your private macros replaced by their more basic things.
Related
I really wonder, why even recent systems of Tex/Latex do not use any caching to speed up later runs. Every time that I fix a single comma*, calling Latex costs me about the same amount of time, because it needs to load and convert every single picture file.
(* I know that even changing a tiny comma could affect the whole structure but of course, a well-written cache format could see the impact of that. Also, there might be situations where 100% correctness is not needed as long as it’s fast.)
Is there something in the language of Tex which makes this complicated or impossible to accomplish or is it just that in the original implementation of Tex, there was no need for this (because it would have been slow anyway on those large computers)?
But then on the other hand, why doesn’t this annoy other people so much that they’ve started a fork which has some sort of caching (or transparent conversion of Tex files to a format which is faster to parse)?
Is there anything I can do to speed up subsequent runs of Latex? Except from putting all the stuff into chapterXX.tex files and then commenting them out?
Let's try to understand how TeX works. What happens when you write the following?
tex.exe myfile.tex
TeX reads your file byte by byte. First of all, TeX converts each char to pair <category, ascii-code>. Each character has category code and ascii code. Category code means that the character is an opening brace ({) or entrance into the mathematical mode ($), symbol-macro (~, for example) or letter (A-Z,a-z).
If TeX gets chars with category code 11 (letters) or 12 (other symbols: digits, comma, period) TeX starts a paragraph. You want to cache all paragraphs.
Suppose you changed something in your document. How can TeX check that all paragraphs after your changes is the same? May be you changed the category of some char. Me be you changed the meaning of some macro. Or you have removed } somewhere and thus changed the current font.
To be sure that the paragraph is the same you must be sure that all characters in the paragraph is the same, that all character categories is the same, the current font is the same, all math fonts is the same, and the value of some internal variables is the same (for example, \hsize, \vsize, \pretolerance, \tolerance, \hypenpenalty, exhyphenpenalty, \widowpenalty, \spaceskip, ..., ........)
You can be sure only that all paragraphed before your changes is the same. But in this case you must keep all states after each paragraph.
Your system SuperCachedTeX is very complicated. Isn't it?
If you're using pdftex, then you can use --draftmode on the command line for the first runs. This instructs pdftex not to generate a PDF.
Of course lots of things could be cached (like graphics information, for instance), but the way TeX works makes it hard to do. There is a rather complex initialization of TeX when it starts up, and one TeX run always means exactly one PDF written out. In order to do caching, you need to keep the data in memory (to be efficient).
You could use IPC and talk to a daemon to get the cached information. But that would involve lots programming. TeX is for normal purposes so blazingly fast, that this does not really gain a lot. But on the other hand, this is a good question, as I have seen LaTeX runs (on currend hardware) that run > 10 hours that would have benefited from caching.
Yet another answer, not strictly related:
You can use the LaTeX macro \include{...} and with \includeonly{} you can rerun your document for a subset only. But this is not caching, nor does it give you the complete document.
There are solutions such as preview-latex, which pre-compile stuff into a dedicated format file for speed purposes. You need to remember that TeX optimises pages on a local basis. There is no concpet at the engine level of material being fixed on a particular page, so you can't just "re-TeX one page".
Actually, the correct answer is (IMO): LaTeX already caches information in its output file (.aux, additional files for other packages). So if you add a comma, this information is reused and thus the typeset run is much faster then without this .aux file.
Tex does have a caching facility, named format files, and I think, pace Alexey's valuable summary of the problems representing Tex's state, it should be possible to use them to allow resumption of editing after any page eject.
The major issue is that pagebreaks will affect paragraphs or floats, and these may not occur at a particular point in the text, but may be occur in the execution of macros that were invoked dependent on the transient state passed to them when they were invoked.
So to make the idea of creating "breakpoints" work, one would need to hack Tex internals to dump additional information, beyond that normaally dumped in format files, and package them up with the state of the auxiliary files. Given what Joseph says about Tex fragment previewers, why would anyone bother hacking Tex to do this?
As a programmer, I wonder if I could create my own package for LaTeX. I need something like that famous "listings" package, but something that is much more capable for my needs. I look for a listings solution that would watch out for a comment line like
// BEGIN LISTING 3122
// END LISTING 3122
No syntax highlighting, but intelligent support for tab indents. That package then would be used with a file name or path, walk through the lines and copy out just the snippets of interest.
I am 100% sure there is absolutely nothing like this on the market. So I want to program it for LaTeX. If that's possible. I have no idea how and what programming language / IDE. Where would I start looking?
This is certainly possible, but it is non-trivial in the TeX programming language. I don't have time to code it up at the moment but here's an algorithm; I suggest asking on comp.text.tex for more specific LaTeX programming advice.
Locally set all catcodes of special chars to "other" (\dospecials) and start reading in the input file line by line (\read)
for each line compare the first however many tokens of the line (some iterative use of \if or \ifx; there might be a package to make this easier such as stringstrings or xstring)
in the default state throw away the input line and read the next
unless it's // BEGIN LISTING, in which case save each line into a macro (something like \g#addto#macro)
until it's // END LISTING, obviously
keep going until the end of the file (\ifeof)
TeX by Topic is a good reference guide for this sort of work.
The rather simple texments package shows how code can be piped into pdflatex: by writing your shell-invocable filter, you should be able to do something similar with your idea.
I'm pretty certain you can't do this in LaTeX. Basically you can go nuts with anything that's either a command (\foo) or an environment (\begin{foo} ... \end{foo}) but not in the way you are describing here. Within environments or commands it is possible to turn off LaTeX's processing and handle everything yourself in some way. This is how verbatim and listings work. It's not very pretty though.
Basically, I think it might be possible, if you make ‘/’ an active character (there is \makeactive for example but I imagine there are more solutions) and then invent some good magic around it. (You will need to emulate/create an environment with your logic.) Similar things are done in some of the internationalisation packages in order to ease the input of letters with diacritics.
For a character like ‘/’ this might be even harder as this one could have been written in other places of your text, too. So of course you’d have to take special care for that.
I want LaTeX to automatically replace strings like " a ", " s ", " z " with " a~", " s~", " z~", because they can't be at line end. Any suggestions?
For Czech typographic rules, there is a preprocessor called Vlna" by Petr Olšák - download . The set of (usually prepositions in czech) is customizable - so it might be usable for other languages as well.
You can use \StrSubstitute from xstring package.
e.g.
\StrSubstitute{change ME}{ ME}{d}
will convert change ME into changed.
Although, nesting is not possible, so to make another substitution you must use an intermediate variable in this way
\StrSubstitute{change ME}{ ME}{d}[\mystring]
\StrSubstitute{\mystring}{ed}{ing}
Finally, your solution would be
\usepackage{xstring}
\def\mystring{...source string here...}
\begin{document}
\StrSubstitute{\mystring}{ a }{a~{}}[\mystring]
\StrSubstitute{\mystring}{ s }{s~{}}[\mystring]
\StrSubstitute{\mystring}{ z }{z~{}}[\mystring]
\mystring
\end{document}
Note the use of the empty string {} to avoid the sequence ~}.
I'm afraid (to the best of my knowledge) this is basically impossible with LaTeX. A LuaTeX-based solution might be possible, though.
It's not actually clear to me, however, that " a ", for example, shouldn't appear at the end of a
line. Although I might be used to different typographic rules.
(Is there anything wrong with the line break in the last paragraph? :))
As far as I know there is no way to do this in LaTeX itself. I'd go for automating this with some external tools, as my typical setup involves a Makefile handling the LaTeX run by itself. This makes it rather easy to run tools like sed on the sources and do some replacements using regular expressions, and a simple rule would do this for your case.
If you use some LaTeX editor that does everything for you you should check the editors regular expression search and replace functionality.
Yes, this is the age old argument of data processing vs. data composition. We have always done these things in a pre-processor environment responsible for extracting the information from its source environment, SQL or plain-text, and created the contents of a \input(file.tex).
But yes, it is possible (TeX is after all a programming language) but you will have to become a wizard. Get the 4 volume set TeX in Practice by Stephan von Bechtolsheim.
The approach would be to begin an environment (execute a macro) whose ''argument'' was all text down to the end of the environment. Then just munge though the tokens fixing the ones you want.
Still, I don't think any of us are advocating this approach.
If you are using TeXmaker to write your LaTeX file, then you may click on the Edit button on the toolbar, then click on Replace.
A dialogue box will come up, and you can enter your strings one after the other.
You put the strings to be changed in the Find text input and what you want it to be changed to in the Replace text input.
You can also specify where you want the replacement to start from.
Click Find and Replace (or similiar) in the menu of your text editor and do it.
When I write math in LaTeX I often need to perform simple arithmetic on numbers in my LaTeX source, like 515.1544 + 454 = ???.
I usually copy-paste the LaTeX code into Google to get the result, but I still have to manually change the syntax, e.g.
\frac{154,7}{25} - (289 - \frac{1337}{42})
must be changed to
154,7/25 - (289 - 1337/42)
It seems trivial to write a program to do this for the most commonly used operations.
Is there a calculator which understand this syntax?
EDIT:
I know that doing this perfectly is impossible (because of the halting problem). Doing it for the simple cases I need is trivial. \frac, \cdot, \sqrt and a few other tags would do the trick. The program could just return an error for cases it does not understand.
WolframAlpha can take input in TeX form.
http://blog.wolframalpha.com/2010/09/30/talk-to-wolframalpha-in-tex/
The LaTeXCalc project is designed to do just that. It will read a TeX file and do the computations. For more information check out the home page at http://latexcalc.sourceforge.net/
The calc package allows you to do some calculations in source, but only within commands like \setcounter and \addtolength. As far as I can tell, this is not what you want.
If you already use sage, then the sagetex package is pretty awesome (if not, it's overkill). It allows you get nicely formatted output from input like this:
The square of
$\begin{pmatrix}
1 & 2 \\
3 & 4
\end{pmatrix}$
is \sage{matrix([[1, 2], [3,4]])^2}.
The prime factorization of the current page number is \sage{factor(\thepage)}
As Andy says, the answer is yes there is a calculator that can understand most latex formulas: Emacs.
Try the following steps (assuming vanilla emacs):
Open emacs
Open your .tex file (or activate latex-mode)
position the point somewhere between the two $$ or e.g. inside the begin/end environment of the formula (or even matrix).
use calc embedded mode for maximum awesomeness
So with point in the formula you gave above:
$\frac{154,7}{25} - (289 - \frac{1337}{42})$
press C-x * d to duplicate the formula in the line below and enter calc-embedded mode which should already have activated a latex variant of calc for you. Your buffer now looks like this:
$\frac{154,7}{25} - (289 - \frac{1337}{42})$
$\frac{-37651}{150}$`
Note that the fraction as already been transformed as far as possible. Doing the same again (C-x * d) and pressing c f to convert the fractional into a floating point number yields the following buffer:
$\frac{154,7}{25} - (289 - \frac{1337}{42})$
$\frac{-37651}{150}$
$-251.006666667$
I used C-x * d to duplicate the formula and then enter embedded mode in order to have the intermediate values, however there is also C-x * e which avoids the duplication and simply enters embedded mode for the current formula.
If you are interested you should really have a look at the info page for Emacs Calc - Embedded Mode. And in general the help for the Gnu Emaca Calculator together with the awesome interactive tutorial.
You can run an R function called Sweave on a (mostly TeX with some R) file that can replace R expressions with their results in Tex.
A tutorial can be found here: http://www.scribd.com/doc/6451985/Learning-to-Sweave-in-APA-Style
My calculator can do that. To get the formatted output, double-click the result formula and press ctrl+c to copy it.
It can do fairly advanced stuff too (differentiation, easy integrals (and not that easy ones)...).
https://calculator-algebra.org/
A sample computation:
https://calculator-algebra.org:8166/#%7B%22currentPage%22%3A%22calculator%22%2C%22calculatorInput%22%3A%22%5C%5Cfrac%7B1%2B2%7D%7B3%7D%3B%20d%2Fdx(arctan%20(2x%2B3))%22%2C%22monitoring%22%3A%22true%22%7D
There is a way to do what you want just not quite how you describe.
You can use the fp package (\usepackage[options]{fp}) the floating point package will do anything you want; solving equations, adding dividing and many more. Unfortunately it will not read the LaTeX math you instead have to do something a little different, the documentation is very poor so I'll give an example here.
for instance if you want to do (2x3)/5 you would type:
\FPmul\p{2}{3} % \p is the assignment of the operation 2x3
\FPupn\p{\p{} 7 round} % upn evaluates the assignment \p and rounds to 7dp
\FPdiv\q{\p}{5} % divides the assigned value p by 5 names result q
\FPupn\q{\q{} 4 round} % rounds the result to 4 decimal places and evaluates
$\frac{2\times3}{5}=\FPprint\q$ % This will print the result of the calculations in the math.
the FP commands are always ibvisible, only FPprint prints the result associated with it so your documents will not be messy, FP commands can be placed wherever you wish (not verb) as long as they are before the associated FPprint.
You could just paste it into symbolab which as a bonus has free step by step solutions. Also since symbolab uses mathquill it instantly formats your latex.
Considering that LaTeX itself is a Turing-complete markup language I strongly doubt you can build something like this that isn't built directly into LaTeX. Furthermore, LaTeX math matkup itself has next to no semantic meaning, it merely describes the visual appearance.
That being said, you can probably hack together something which recognizes a non-programmable subset of LaTeX math markup and spits out the result in the same way. If all you're interested in is simple arithmetics with fractions and integers (careful with decimal fractions, though, as they may appear as 3{,}141... in German texts :)) this shouldn't be too hard. But once you start with integrals, matrices, etc. I fear that LaTeX lacks expressiveness to accurately describe your intentions. It is a document preparation system, after all and thus not very suitable as input for computer algebra systems.
Side note: You can switch to Word which has—in its current version—a math markup language which is sufficiently LaTeX-like (by now it even supports LaTeX markup) and yet still Google-friendly for simpler terms:
With the free Microsoft Math add-in you can even let Word calculate expressions in-place:
There is none, because it is generally not possible.
LaTeX math mode markup is presentational markup and there are cases in which it does not provide enough information to calculate the expression.
That was one of the reasons MathML content markup was created and also why MathML is used in Mathematica. MathML actually is sort of two languages in one:
presentation markup
content markup
To accomplish what you are after you'll have to have MathML with comibned presentation and content markup (see MathML spec).
In my opinion your best bet is to use MathML (even if it is verbose) and convert to LaTeX when necessary. That said, I also like LaTeX syntax best and maybe what we need is a compact syntax for MathML (something similar in spirit to RelaxNG compact syntax).
For calculations with LaTeX you can use a CalcTeX package.
This package understand elements of LaTeX language and makes an calculations, for example your problem is avialble on
http://sg.bzip.pl/CalcTeX/examples/frac.tgz
or just please write
\noindent
For calculation please use following enviromentals
$515.1544 + 454$
or
\[ \frac{154.7}{25}-(289-\frac{1337}{42.})
\]
or
\begin{equation}
154.7/25-(289-1337/42.)
\end{equation}
For more info please visite project web site or contact author of this project.
For performing the math within your LaTeX itself, you might also look into the pgfmath package, which is more powerful and convenient than the calc package. You can find out how to use it from Part VI of The TikZ and PGF Packages Manual, which you can find here (version 2.10 currently): http://mirror.unl.edu/ctan/graphics/pgf/base/doc/generic/pgf/pgfmanual.pdf
Emacs calc-mode accepts latex-input. I use it daily. Press "d", followed by "L" to enter latex input mode. Press "'" to open a prompt where you can paste your tex.
Anyone saing it is not possible is wrong.
IIRC Mathematica can do it.
There is none, because it is generally not possible. LaTeX math mode
markup is presentational markup and there are cases in which it does
not provide enough information to calculate the expression.
You are right. LaTeX as it is does not provide enough info to make any calculations.Moreover, it does not represent any information to do it. But nobody prevents to wright in LaTeX format a text that contains such an information.
It is a difficult path, because you need to build a system of rules superimposed on what content ofthe text in Latex format needs to contain that it would be recognizable by your interpreter. And then convince the user that it is necessary to learn, etc. etc...
The easiest way to create a logical and intuitive calculator of mathematical expressions. And the expression is already possible to convert latex. It's almost like what you said. This is implemented in the program which I have pointed to. AnEasyCalc allows to type an expression as you type the plane text in any text editor. It checks, calculates and generate LateX string by its own then. Its very easy and rapid work. Just try and you will see that.
This is not exactly what you are asking for but it is a nice package
that you can include in a LaTeX document to do all kind of operations including arithmetic, calculus and even vectors and matrices:
The package name is "calculator"
http://mirror.unl.edu/ctan/macros/latex/contrib/calculator/calculator.pdf
The latex2sympy2 Python library can parse LaTeX math expressions.
from latex2sympy2 import latex2sympy
tex_str = r"""YOUR TEX MATH HERE"""
tex_str = r"\frac{9\pi}{\ln(12)}+22" # example TeX math
sympy_object = latex2sympy(tex_str)
evaluated_tex = float(sympy_object.evalf())
print(evaluated_tex)
This Python 3 code evaluates 9𝜋/ln(12)+22 (in its LaTeX from above) to 33.37842899841745.
The snippet above only handles basic algebraic simplification (math expressions without variables). Since the library converts LaTeX math to SymPy objects, the above code can easily be tweaked and extended to handle much more complicated LaTeX math (including solving derivatives, integrals, etc...).
The latex2sympy2 library can be installed via the pip command: pip install --user latex2sympy2
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try the AnEasyCalc program. It allows to get the latex formula very easy:
http://steamandwater.od.ua/AnEasyCalc/
:)
Are there any conventions for formatting console output from a command line app for readability and consistency? For instance, do you indent sub-information, when do you print a blank line, if ever, how should you accent important statements.
I've found output can quickly degenerate into a chaotic blur. I'm interested in hearing about what other people do.
Update: Really this is for embedded software which spits debug status out a terminal, but it's pretty much like a console app, and I figured everyone would be more familiar with that. Thanks so far.
I'd differentiate two kinds of programs:
Do you print information that might be used by a script (i.e. it should be parseable)? Then define a pretty strict format and use only that (for example fixed field separators).
Do you print information that need not be parsed by a script (or is there an alternative script-parseable format already)? Then write what comes natural:
My suggestions:
write it so that you would like to read it
indent sub-information 2 or 4 spaces, definitely not more
separate blocks of information by one empty line at most
respect the COLUMN environment variable (and possible ROWS if it applies to your output).
If this is for a *nix environment, then I'd recommend reading Basics of Unix Philosophy. It's not specific to output but there are some good guidelines for command line programs in general.
Expect the output of every program to become the input to another, as yet unknown, program. Don't clutter output with extraneous information. Avoid stringently columnar or binary input formats. Don't insist on interactive input.