DocOnce Troubleshooting and FAQ

Authors:Hans Petter Langtangen
Date:Jun 22, 2016


DocOnce has some support for syntax checking. If you encounter Python errors while running doconce format, the reason for the error is most likely a syntax problem in your DocOnce source file. You have to track down this syntax problem yourself. However, DocOnce applies regular expressions to a large extent for transforming text, and regular expressions may sometimes lead to undesired results. Therefore, there is a chance that legal DocOnce syntax is not treated properly. The section Examples on seemingly legal syntax that fails gives some examples of what can go wrong.

General topics

How can I study error messages and warnings from DocOnce?

The output from DocOnce and later compilation by various tools can be overwhelming in the terminal window. Fortunately, DocOnce also writes its warnings and error message to mydoc.dlog if is the name of the DocOnce root file. It is recommended to study mydoc.dlog and correct anything that leads to warnings or errors without abortion.

How do I debug a DocOnce file that results in a strange error message?

First, do doconce clean to clean up all old files and recompile. Run pdflatex or latex since that checks for errors in your math formulas and is stricter on syntax than many other output formats like html and sphinx. Fortunately, DocOnce performs syntax checking on many constuctions that just lead to plain errors in LaTeX.

If you have a document consisting of a file or two, you can isolate the problem by a “bisection” method: split the file in two, compile both parts, continue with the part that gave the problem, and repeat the process. This will quickly narrow down the text so you ultimately understand the problem.

If you have a big book, it can be difficult to track down where the error is. If the error comes from LaTeX compilation, go to the main file’s .tex file. Say the main document is Then find the line with the reported error message in mydoc.tex, find the cause of the error, and correct the error in the corresponding DocOnce source file. To find this file, try to recognize in mydoc.tex where in the document you are. Find some phrase that X potentially can be unique and to a Unix find command on X:

Terminal> find ../chapters -name '*.do.txt' -exec grep X {} \; -print

Hopefully, the output indentifies the right DocOnce source file.

If the error is a Mako error, you have to search in the file: this is the file resulting from the running the Preprocess and Mako programs, and the file is therefore the actual text that DocOnce translates.

In a big project, thre is usually some main file with a lot of #include statements. Go to this file,, and “remove” the include statements by just removing the final e in include: #includ. Now can you can easily compile the subdocuments one by one. Start with one document file and bring in new files for inclusion until the problem appears for the first time. Then you have isolated the problematic file. It might be necessary to compile only this file. To this end, it might be necessary to insert Mako code in the beginning of the file, and specify certain command-line arguments, especially --allow_refs_to_external_docs so you do not get errors from missing labels that are defined elsewhere in the original big document.

Eventually, you have tracked down the erroneous piece of text, but perhaps you do not understand why. Then you just have to rewrite the text to something that compiles.

Translation aborts when labels are not defined

By default, the DocOnce translation aborts when references are found to lables not defined in the document (i.e., labels in other documents). This abortion can be annoying, and although it can be nullified by --no_abort, that option also ignores other error messages. Instead, use --allow_refs_to_external_docs to allow references to labels in other documents (these references will of course not work).

References to labels in other documents should anyway appear inside generalized references, see the Generalied Cross-Referencing section in the manual.

How to I control the table of contents?

To include a table of contents in the document, insert the line

TOC: on

in the DocOnce source at the place where you want the table of contents to be inserted. Often you want to do a pagebreak before the table of contents, and in that case, insert !split on the line before.

To control the number of section levels in the table of contents (chapters, sections, subsections), use the --toc_depth=X command-line option, where X reflects the maximum level. Level 0 correspond to chapter. The defaul value of X, 2, thus means including chapters, sections, and subsections. For Sphinx output, one must use the command-line option toc_depth=X as part of the command doconce sphinx_dir.

Why are underscores in text a potential problem?

Underscores in plain text are not tolerated by LaTeX, but works fine in other formats. In LaTeX, such underscores can give different obscure error messages, depending on the context. The remedy is to typeset all words with underscores in inline verbatim, e.g.,

If you choose the `Enable_access` menu, ...

The downside is that the word with underscores is typeset in monospace font.

The standard remedy in LaTeX is to insert a backslash before the underscore:

If you choose the Enable\_access menu, ...

but the backslash is not wanted in other formats. A Mako function can fix this:

def underscorephrase(phrase):
    if FORMAT in ('pdflatex', 'latex'):
        return phrase.replace('_', '\\_')
        return phrase

# Some text:
If you choose the ${underscorephrase('Enable_access')}, ...

GitHub gh-pages will not display files starting with a dot or underscore

This is a typical problem related to publishing either splitted HTML documents or Sphinx versions of documents on GitHub, using a gh-pages branch. Filenames starting with a dot (as in ._mydoc001.html) or located in a directory whose name starts with an underscore (as in spninx/_static) will not be properly shown in HTML if not the root directory of the gh-pages branch contains a file .nojekyll. This file can be empty. A typical fix is

Terminal> git checkout gh-pages
Terminal> touch .nojekyll
Terminal> git add .nojekyll
Terminal> git commit -am updates
Terminal> git push origin gh-pages

GitHub gh-pages will not display files

A common error is to link to addresses starting with rather than the required

“Blank line is illegal in latex block”, but there is no blank line

Are you compiling for sphinx, ipynb, pandoc? In that case, align environments are rewritten as sequences of plain equation environments (since MathJax for these output formats does not support numbered equations in align). If a linebreak \\ in the align environment appears on its own line, this line will be blank in the equation environment and cause the error message. Simply move the linebreak up at the end of the preceding line.

Note: This kind of errors are now automatically removed (since Dec, 2015).

A newline in equations (double backslash) becomes single backslash and eats up spaces

This is a problem with the Mako preprocessor and files that have been edited on Windows. The remedy is to change the newline character on Windows to that in Unix:

Terminal> doconce subst '\r\n' '\n'

If you work on Windows, you probably have to avoid using the Mako preprocessor (it is not used unless you use Mako functions, variables, or control statements).

Preprocess error: unexpected EOF while parsing

This error may arise from a syntax error with a colon at the end of if tests, e.g. # #if FORMAT == 'html':. Colon is not used with Preprocess (but required by Mako: if FORMAT == 'html':).

When I set a large portion of text in color, only a part of it becomes colored

Although DocOnce features a color inline tag (color), this tag will most likely fail for large portions of text. The reason is that this tag, like most other DocOnce constructions, relies on a regular expression for being detected. The regular expression searches for opening and closing braces after the color{red} specification. The closing brace is the first brace encountered. Therefore, if you have any text containing a right brace inside the text to be colored, the first right brace will define the end of the coloring. Here is an example:

color{blue}{Here is some text
to be typeset in blue.

===== Here is a new subsection =====

More text to be typeset in blue, but the right brace in the label
will end the coloring. There is no way out of this except for
moving constructions with braces (`label`, `cite`) out of the
text to be colored.

How can I make use of a native LaTeX environments (example environment for instance)?

LaTeX writers often lack their favorite environments, but DocOnce has a way to define such environments, with corresponding typesetting also for HTML and all other output formats. See the section User-Defined Environments in the DocOnce manual. It contains all the details for using a standard example or theorem environment in LaTeX output.

How can I create a more tailored code environment in LaTeX than what DocOnce offers?

It is easy with user-defined environments, see such an example at the end of the document Demonstration of DocOnce support for LaTeX code block environments. Description of user-defined environments are found in the DocOnce manual.

Movies will not play in my broswer

Are you using Safari as browser? It will not play Ogg and WebM movies. A message in a box should notify you about this (right below the movie player).

Reveal slides look strange in the browser

Are you using Safari as browser? reveal.js slides work best in Firefox, Chrome, or Opera.

How can I control the vertical spacing in slides?

HTML5 and LaTeX slides control the spacings for you. However, sometimes you really want to add some space. The <linebreak> is effective for this purpose. For example,

!bblock (large) So - how to be excellent?
Excellence is not a planned goal - it is the corollary of
deep passion, very much hard (and exciting!)
work, and *thinking constantly about it*.

is rendered as

So - how to be excellent

Excellence is not a planned goal - it is the corollary of

deep passion, very much hard (and exciting!) work, and thinking constantly about it.

The <linebreak> is a newline in LaTeX if it has preceding text, otherwise it is a \vspace{3mm}. In HTML, <linebreak> is <br>.

More vertical space is obtained by repeated use of <linebreak>:


How do I get “Figure” written in another language?

DocOnce documents can be written in any language, but figure captions typically contain the English word “Figure”. This must be fixed by auto-editing the output file after translation by doconce format.

In LaTeX you can use your native language package, e.g.,

doconce replace '% insert custom LaTeX commands...' '\\usepackage[norsk]{babel} mydoc.tex

to get the Norwegian language.

In other formats you have do more manual substitutions:

doconce replace Figure Figur mydoc.html
doconce replace figure figur mydoc.html

or both in one command using regular expressions:

doconce stubst '([Ff]igur)e' '\g<1>' mydoc.html

Spellcheck reports mistakes that I cannot find

The doconce spellcheck command strips off a lot of text (math, code, syntax tags) before it starts spellchecking. The spellchecked text is therefore different from the doconce source! Fortunately, the file that is actually spellchecked can be examined. If the spellcheck command is

doconce spellcheck mydoc

the file contains the text that is actually run through the spellchecker (ispell). Search for the misspelled word there and try to find it in the doconce source code. Very often, strange misspellings come from a syntax typo that has led to a strange word in the stripped version.

Wrong typesetting of mathematics can lead to strange errors, e.g., misspellings such as iu because of some math f_iu_i that is not properly typeset between dollar signs. Here are some useful grep commands to search for such errors:

grep --color=auto -E '\biu\b'
grep --color=auto -E ' iu'
grep --color=auto -E 'iu '
grep --color=auto -E 'iu'

Text between subexercises are moved

If you insert text between a !esubex and the next !bsubex, this text is moved before all the subexercises. This is a feature, not a bug (exercises have certain elements: main text, subexercises, hints, etc. that are typeset in a specific order, which may be different from what appears in the DocOnce source file). If you need a comment between two subexercises, just place the comment at the end of the previous subexercise.

DocOnce aborts because of a syntax error that is not an error

DocOnce searches for typical syntax errors and usually aborts the execution if errors are found. However, it may happen, especially in verbatim blocks, that DocOnce reports syntax errors that are not errors. To continue execution, simply add the --no_abort option on the command line. You may send an email to the DocOnce author at and report the problem.

Figure captions are incomplete

If only the first part of a figure caption in the DocOnce file is seen in the target output format, the reason is usually that the caption occupies multiple lines in the DocOnce file. The figure caption must be written as one line, at the same line as the FIGURE keyword.

Problems with boldface and emphasize

Two boldface or emphasize expressions after each other are not rendered correctly. Merge them into one common expression.

Inline comment does not handle verbatim or emphasis right

Inline comments lead (in LaTeX output formats) to shortened titles for a table of inline comments, and the shortening is done naively: the title can cut a verbatim expression in the middle. There is no other way around that to rewrite the inline comment. (The title consists of the first 50 characters or so of the text.

Inline verbatim code or boldface is not detected when used with a footnote

There must be a space between the verbatim code (or boldface words) and the footnote bracket:

The construction `def f(x,y):`[^whitespace] is standard.

[^whitespace]: Well, a space before the `y` argument, as in `f(x, y)`,
would be the standard.

Inline verbatim code is not detected

Make sure there is a space before the first back-tick.

Inline verbatim text is not formatted correctly

Make sure there is whitespace surrounding the text in back-ticks.

Strange non-English characters

The former reason for this problem is that DocOnce could only work with latin1 (ISO-8859) encoding and not UTF-8. After May 2013, DocOnce applies UTF-8 both for HTML and LaTeX.

Check the encoding of the .do.txt file with the Unix file command or with

Terminal> doconce guess_encoding

If the encoding is different from ASCII or UTF-8, say latin1, convert to UTF-8 using either of the Unix commands

Terminal> doconce change_encoding latin1 utf-8
Terminal> iconv -t utf-8 -f latin1 --output newfile

Wrong Norwegian characters

When DocOnce documents have characters not in the standard ASCII set, the format of the file must be UTF-8. See the section “Strange non-English characters” above for how to run doconce change_encoding to change the encoding of the DocOnce file.

Too short underlining of reST headlines

This may happen if there is a paragraph heading without proceeding text before some section heading.

Found !bt but no tex blocks extracted (BUG)

This message points to a bug, but has been resolved by removing blank lines between the text and the first !bt (inserting the blanks again did not trigger the error message again...).

Examples are typset with environment delimiters visible

If you see an Example section containing !bsubex, !bsol, or other begin and end tags for environments, it means that you have intended to typeset examples as exercises, but forgotten the command-line option --examples_as_exercises. The text in the example is typeset as is unless this option is included.

Emacs editing does not work properly because of “regexp overflow”

Sometimes the Doonce editing mode (see the Emacs DocOnce Formatter section in the manual) in Emacs leads to an error message ending with “overflow in regexp matcher”. This error is due to some regular expression used in the DocOnce editing mode. The remedy is to split the file into smaller pieces and include the pieces using the preprocess directive #include "". The error message comes with the DocOnce file contains too much text for Emacs to handle.

My machine hangs if I have many movies

DocOnce has no limits on the amount of movies. When the output is in HTML, one big HTML file may contain too many movies (local movie files or embedded YouTube movies) for the browser to handle. The remedy is to split the document into smaller pieces by inserting


for every new page. After doconce format html mydoc, run doconce split_html mydoc.html to get the document split into a main document mydoc.html and pieces ._mydocXXX.html, where XXX stands for three digits (000, 001, 002, and so forth).

Conversion from DocOnce to Google Docs

Convesion from Google Docs to DocOnce

This solution is not much explored and more text transformations from Pandoc-generated Markdown is certainly needed.

Are there any tools for shared online writing of DocOnce documents?

In theory, and can be used to share Markdown documents and these can be transform to and from DocOnce documents. Tested to a little degree, but may work for very simple documents (sections, lists, code - no labels, refs, math, admons, code copied from file). Not all of Extended Markdown is interpreted by DocOnce, and DocOnce transforms to Panddoc-extended Markdown, not the Extended Markdown used by these sites.

How can I make books from DocOnce? supports HTML input with WordPress LaTeX mathematics, so the easiest way is to compile DocOnce to HTML with the --wordpress option, put the file on the web somewhere, click Utilities - Import in, then choose HTML input, write the URL, and upload.

Note that WordPress LaTeX cannot refer to equations using labels! This is a major problem with

How can I produce ePub books from DocOnce?

DocOnce has no direct translation to ePub, but one can apply a script to translate a set of split HTML files to ePub. Bootstrap styles with mathematics and code come out very nice in ePub this way. The script needs a JSON file. If is the DocOnce file and ._mydoc*.html the set of split HTML files after translation to HTML, the JSON file may look like this:

    "filename" : "mydoc",
    "title" : "Title of the document",
    "authors" : [
            "name" : "Hans Petter Langtangen",
            "sort" : "Langtangen, Hans Petter"
    "rights" : "Public Domain",
    "language" : "en",
    "publisher": "hpl",
    "subjects" : [ "Science" ],
    "contributors" : [
            "name" : "Hans Petter Langtangen",
            "role" : "author"
    "identifier" : {
        "scheme" : "URL",
        "value" : ""
    "contents" : [
            "type" : "text",
            "source" : "._mydoc*.html"
    "toc" : {
        "depth" : 2,
        "parse" : [ "text" ],
        "generate" : {
            "title" : "Index"

Just edit this file to your needs, save it as mydoc.json and run mydoc.json to produce mydoc.epub. Read in Calibre on computers or use ebook readers on phones and tablets.

What about non-English languages and DocOnce?

DocOnce can handle non-English language, although most of its use has concerned documents in English. When writing in languages with non-ASCII characters, remember to use the command-line option --encoding=utf-8. Some other points of importance:

  • The abstract requires a heading Summary or Abstract. This heading must be substitued by the appropriate word after translation.
  • LaTeX files should make use of packages and options for the language in question such that LaTeX-generated headings get the right language-specific wording. Use doconce replace or doconce search modify the .tex file (see the Bash script referred to below for examples).
  • Some DocOnce-generated headings are in English, e.g., “Table of Contents”, which must be edited by doconce replace.
  • For Sphinx output, two edits in files in the Sphinx root directory (sphinx-rootdir by default) are necessary (see Bash script below for examples on autoediting):
    • Insert right language in language = 'nb_NO' for Norwegian
    • Edit headings in index.rst: “Contents:” and “Tables and indices”, to what the language demands
    • Unfortunately, “Page contents”, “Next page”, and “Previous page” remains in English in the navigation area (these can, of course, be replaced in all the HTML files generated by Sphinx in _build/html - recall to edit also all the files starting with a dot if you have split the document (doconce split_rst))

There is an example of a document in Norwegian in the DocOnce repository where we do all necessary adjustments mentioned above:

Lists look wrong

It is very important to be accurate with white space in lists. There must be exactly one blank between the o or * that starts an item and the following text, and multiple lines in an item must be perfectly aligned. Here are some typical errors:

o a rectangular pulse
o  a Gaussian pulse
o one period of a cosine pulse
o half a period of
 a cosine pulse

Problem: a Gaussian pulse is not properly aligned, a cosine pulse on the last line is not properly aligned. The correct formatting is

o a rectangular pulse
o a Gaussian pulse
o one period of a cosine pulse
o half a period of
  a cosine pulse

How can I get an overview of all files that are included in a document?

Suppose the root (main) document is Run

Terminal> doconce include_map

The output lists all the recursive #include Preprocess statements so you can see how all files are included.

How to write the dollar sign for an amount in dollars?

If you want to write $1,000, this is not trivial, because the dollar sign is used for inline math formulas, and everything from this dollar sign up to the next is interpreted as a math formula.

The solution in DocOnce is to prefix the dollar sign by a backslash (same syntax as required by LaTeX). This ensures correct output in all output formats.

Another solution is to pre- or postfix the amount by USD instead of the dollar sign.

Problems with Externaldocuments specifications

The # Externaldocuments: command is used for generalized references to lables in other documents. The command specifies directories with .aux files and provides the necessary information for using xr package for external references in case of LaTeX output. For all other formts an alternative user-given text is used and # Externaldocuments: has no effect. A typical use case is that one book refers to another book. This may cause trouble when the .tex and .aux files specified in the # Externaldocuments: command do not exist. A quick fix is to follow the advice in the error message and use the touch command to create empty files so DocOnce does not abort the execution. However, the only real fix is to install all the directory trees specified in the # Externaldocuments: command.

References to such external documents may also cause trouble when sending the .tex files for a book to a publisher, since the \externaldocument{} commands in the .tex file in this file will refer to .aux files in other directories (which the publisher then must have). A good fix to this problem is provided by the sample packing script, which calls up another script, which automatically copies the .aux files in question to a subdirectory and autoedits the main .tex for the DocOnce document accordingly. The purpose of is to make a directory tree with all files (including stylefiles) needed to compile a LaTeX version of the document. This tree can then be sent to the publisher and is self contained.

Another fix for problems with the # Externaldocuments: command is to hardcode references when files needs to be sent to a publisher. Typically, one has

# Externaldocuments: ../../some/path, ../some/other/path
% endif

Every generalized reference to a label in the specified external documents must have a special case when files are meant for a publisher:

ref[Section 4.2][ in
% else:
ref[Section ref{my:label}][ in
cite {book}][the section ``Guidelines'' in the document
"A note on everything": "http://..."].

Setting FOR_PUBLISHER=True as part of the doconce format pdflatex command will then effectively remove everything with the # Externaldocuments: command and generalized references.

What is the difference between doconce replace and doconce subst?

doconce replace replaces one text by another, exactly as the text is written. For example, doconce replace float double *.do.txt is the same as invoking an editor and replacing float by double in all files *.do.txt. On the other hand, doconce subst works with regular expressions, so doconce subst from to is the same as re.sub(from, to) in Python. You need experience with re.sub and regular expressions to take advantage of doconce subst. Regular expressions are much more powerful for editing text, but also more complicated and errorprone.


List important things to remember when programming Mako

The Mako preprocessor is fooled by DocOnce text

Here are possible problems for Mako:

  • Strings with 'T<%.1f' look as openings of Mako blocks (<%); change to 'T < %.1f' to avoid this confusion.

The Mako preprocessor has problems with lines starting with percent sign

If you have lines starting with % inside code segments (for example, SWIG code or Matlab comment lines), the Mako preprocessor will crash because it thinks these lines are Mako statements. DocOnce detects this problem and emits an error message. The solution to this problem is to replace a single % at the very beginning of the line (column 1) inside code by a double %%. Mako will replace it by a single %. However, contrary to what is claimed in the Mako documentation, an indented double %% remains %% and is not converted to % (and using a single % gives a Mako error). The trick is to write ${'%'} as demonstrated here:

!bc mcod
%% Comment on the beginning of the line can be escaped by %%
if a > b
  ${'%'} Indented comment needs this trick
  c = a + b

The Mako preprocessor gives syntax error in Python code

The information with respect to syntax errors in Python code is sparse. It is recommended to move the Python code to separate files and test it with the ordinary Python interpreter. See the section Debugging Python code in Mako in the DocOnce manual.

The Mako preprocessor gives strange error messages

If you to a little syntax error in Mako, the consequences can be quite unpredictable. Especially, if you forget curly braces around variables or function calls, the forthcoming text is processed as part of the Mako command. Pay attention to the line number reported by Mako: this is the line number after Preprocess has processed the DocOnce document, so you need to load and go to the right line in that file to see the Mako problem (here the DocOnce document is named

Look through the specific Mako problems reported below, and if they do not bring you to a solution of the problem, search for all occurences of dollar, left curly brace and check the syntax carefully. Likewise, check the syntax of Mako if-tests.

Another widely used technique is to copy out small parts of the complete document to a separate file and run doconce format. In this way you can easier see which parts of the document that work and where the error suddenly appears.

Tip: Compile your DocOnce document frequently

The best means against Mako problems is to run doconce format often. Combined Git, you can take a git diff to see what you have recently changed and get an idea what can be wrong.

The Mako preprocessor claims a variable is undefined

Very often such errors are related to typos when using Mako variables or functions, or correct yet undesired LaTeX syntax. For example,

${\cal O}(\Delta x^2)$

is valid LaTeX, but the dollar sign and curly braces confuse Mako. Rewrite such mathematics. It is wise to not use ${ anywhere in LaTeX mathematics. Create a newcommand if there are no other possible rewritings. A known common problem is ${}^+$ type of indication of superscripts. A suggested rewrite is $\,{}^+$.

The error message will ask you to rerun doconce with --mako_strict_undefined, which will display the variable that is confusing Mako. Sometimes the variable is printed, sometimes a totally different name is said to be undefined. This is confusing, because then you have to use the bisection method below to narrow down the problem yourself.

Do not continue to use --mako_strict_undefined while you are debugging because this variable or a new variable will then always be undefined in that mode. Rerun without --mako_strict_undefined to see if the problem is gone. If not, try the option again, and if no progress, use # #ifdef directives to comment out large portions of the text and apply a bisection procedure to locate where the Mako problem is (without --mako_strict_undefined). A bisection procedure means that you comment out the last half, find in which half the problem is, comment out half of that half, find in which half the problem is, and so on. The procedure converges pretty quickly, even for large books.

Something goes wrong in the preprocessing step

You can examine tmp_preprocess__filename and tmp_mako__filename, where filename is the complete name of the DocOnce file, to see what the preprocessors actually to and if something is wrong in these files before DocOnce starts translating the text. One or both of those files may be missing, but examine the beginning of the output from DocOnce to see exactly which preprocessors are run and on which files.

Preprocessor directives do not work

Make sure the preprocessor instructions, in Preprocess or Mako, have correct syntax. Also make sure that you do not mix Preprocess and Mako instructions. DocOnce will then only run Preprocess.

Code or Tex Blocks

Too long lines in math blocks

A common problem in LaTeX (not directly related to DocOnce) is too long lines in math blocks. The trick is to use the align or align* environment and introduce newlines with \nonumber\\ to break up lines (without introducing an equation number). Typically,

  1. Insert \nonumber\\ where you see a linebreak should occur.
  2. Start next line with &\quad such that the continuing line starts slightly to the right of the alignment character used to align the equations. If you have only one equation, find some point where you insert & and just start the next line with & - no \quad displacement to the right is needed in that case.
  3. \left( and \right) (and similar constructions for automatic adjustment of the sizes of parentheses) do not work accross linebreaks. This means that you must replace \left( by (e.g.) \biggl( unless there is a corresponding \right on the same line. Whether to choose \biggl, \bigl, or \Biggl depends on the desired size of the the parenthesis.

Code or math block errors in reST

First note that a code or math block must come after some plain sentence (at least for successful output in reST), not directly after a section/paragraph heading, table, comment, figure, or movie, because the code or math block is indented and then become parts of such constructions. Either the block becomes invisible or error messages are issued.

Sometimes reST reports an “Unexpected indentation” at the beginning of a code block. If you see a !bc, which should have been removed when running doconce format sphinx, it is usually an error in the DocOnce source, or a problem with the rst/sphinx translator. Check if the line before the code block ends in one colon (not two!), a question mark, an exclamation mark, a comma, a period, or just a newline/space after text. If not, make sure that the ending is among the mentioned. Then !bc will most likely be replaced and a double colon at the preceding line will appear (which is the right way in reST to indicate a verbatim block of text).

Strange errors around code or TeX blocks in reST

If idx commands for defining indices are placed inside paragraphs, and especially right before a code block, the reST translator (rst and sphinx formats) may get confused and produce strange code blocks that cause errors when the reST text is transformed to other formats. The remedy is to define items for the index outside paragraphs.

Something is wrong with a verbatim code block

Check first that there is a “normal” sentence right before the block (this is important for reST and similar “ASCII-close” formats).

Code/TeX block is not shown in reST format

A comment right before a code or tex block will treat the whole block also as a comment. It is important that there is normal running text right before !bt and !bc environments.

Verbatim code blocks, figures and admons inside lists look ugly

Avoid verbatim code blocks, figures, and admons inside lists (it makes life easier!). Instead, use paragraph headings, say

Step 1. Describe step. Add figure, code block, admon, etc.

Step 2. Describe next step.

If you miss the automatic numbering of items in enumerated lists, you can simulate that with a Mako variable:

<% counter = 0 %>

<% counter += 1 %>
__Step ${counter}.__
Describe step. Add figure, code block, admon, etc.

<% counter += 1 %>
__Step ${counter}.__
Describe next step.

LaTeX code blocks inside lists look ugly

Same solution as for computer code blocks as described in the previous paragraph. Make sure the !bt and !et tags are in column 1 and that the rest of the non-LaTeX surrounding text is correctly indented. Using paragraphs instead of list items is a good idea also here.

LaTeX code appears prior to paragraph headings

If you have a paragraph heading and then code right after,


!bc pycod
def f(x):
    return 42

the generated LaTeX code is correct, but it is translated to PDF in a wrong way such that the heading appears after the code. A remedy is to insert some text after the paragraph heading. See also the section Solution heading in exercise solutions appear after the solution content - it is the same problem.

Numbered equations in exercise solutions change the equation numbers in the text...

This is a problem if you produce versions with and without solutions, see the heading “Numbering of Extra Equations in Solutions” in the DocOnce manual for description of the problem and its solutions.


Math formulas are not rendered properly

HTML generated by Sphinx applies MathJax for rendering LaTeX mathematics. Due to the way Sphinx embeds these formulas in HTML, sometimes the formulas are not being rendered and instead the pure LaTeX code is put in a box. The same formulas may appear right in pure HTML.

The first thing to do is to check that the LaTeX generated PDF format shows the formula correctly. The next step is to compile to HTML and check if MathJax in pure HTML renders the formula correctly. If so, the formula is correctly typeset, and the problem is related to Sphinx.

There are basically two remedies: either drop Sphinx and go for HTML, or try to rewrite the formula and try until the Sphinx-generated HTML code manages to render it.

Copy the problematic typesetting to a minimalistic document. If the original document is split into pieces via doconce split_rst, make sure your minimalistic document also contains a !split command and is split into at least two pieces. This is because equations get tags when documents are split, and with the \tag{} command, it seems that sphinx rewrites the MathJax code, and this may cause problems. This also means that dropping doconce split_rst and having one big HTML file for Sphinx can make the rendering of mathematics (much) easier.

Some typical problems encountered are listed below.

  • Formulas with use of \bar\boldsymbol{}.
  • Align environments with multiple equations. Try to simplify typesetting.
  • \mbox or \hbox commands in equations.

Sphinx directory generation aborts with “label empty or too long”

This is a strange error that might arise from a too long title of the document. The solution is to specify a shorter title when running doconce sphinx_dir (i.e., to avoid getting the title from the original .do.txt document):

Terminal> doconce sphinx_dir title="Short Title" \
          authors="A. B. Crunch" theme=pyramid mydoc

Title level inconsistent

reST does not like jumps in the levels of headings. For example, you cannot have a === (paragraph) heading after a ======= (section) heading without a ==== (subsection) heading in between.

Subsection headings appear at the level of sections in the table of contents

This is a problem that arises if you split a Sphinx document at the subsection level. Then the subsection is the highest level in that part, and it will then move up to the section level in the table of contents (this is done by Sphinx, and DocOnce has no influence on the process).

After Oct 2014, DocOnce ignores by default the !split commands that the user has inserted and performs a split at the highest section level, which means that chapters constitute the parts of the document, if chapters are present, otherwise the sections represent the different parts. If this behavior is not desired and the user’s !split commands are to be respected, provide the command-line argument --sphinx_keep_splits in the doconce format command.

Lists do not appear in .rst files

Check if you have a comment right above the list. That comment will include the list if the list is indentend. Remove the comment.

Error message “Undefined substitution...” from reST

This may happen if there is much inline math in the text. reST cannot understand inline LaTeX commands and interprets them as illegal code. Just ignore these error messages.

Inconsistent headings in reST

The rst2*.py and Sphinx converters abort if the headers of sections are not consistent, i.e., a subsection must come under a section, and a subsubsection must come under a subsection (you cannot have a subsubsection directly under a section). Search for ===, count the number of equality signs (or underscores if you use that) and make sure they decrease by two every time a lower level is encountered.

No code environment appears before “bc ipy” blocks

The !bc ipy directive behaves this way for sphinx output because interactive sessions are automatically handled. If this is not appropriate, shift to !bc cod or another specification of the verbatim environment.


===== Lines are too long

Too long lines are often handled with a forced newline like \\ in LaTeX, but this double backslash does not look good in other formats when you use DocOnce. Try to rewrite the text such that LaTeX naturally avoids too long lines. Inline verbatim can easily force LaTeX to extend the line width, but see if you can use other words to move the inline verbatim to the left or to the next line.

A last resort is to use the preprocessor and test on ``FORMAT == ‘pdflatex’` and then use the double backslash.

Tables get too wide - need to wrap text in the columns

One can use the tabularx package. This is automatically enabled by specifying the alignment of the actual column as X (means l for all other output formats), for instance |---c----X----|.

Table inside user-defined environment does not work

If the table appears at the end of the environment (e.g., a theorem or example environment), add a sentence between the table and the end-of-environment command.

Strange begin{description} error arising from math

If you have an inline math formula that is split over two lines, and the formula continues with a minus sign on a line, this minus sign may be interpreted as a description list and typeset as a list, which is nonsense. The remedy is to move the minus sign at the beginning of the line to the end of the last line.

Inline figures should have more vertical space

You can insert <linebreak> (which gives a vertical space if alone on a line):


FIGURE: [...]


How can I use a special package for typesetting code?K (not pyg, lst, or vrb)

One gets the impression that --latex_code_style= has only the options for Pygments, Listings, or the Verbatim packages, but in fact any package can be used.

Suppose you have the fictitious code enviroment ultimate from the package compcode that you want to use, together with a yellow backgrund, and with some environment-specific parameters arg1 and arg2. Then you can write

Terminal> doconce format pdflatex mydoc --latex_packages=compcode \

The resulting LaTeX code in mydoc.tex becomes


In this way, you can use any environment in any package for typesetting code.

Sphinx and HTML show pygmetized code, but not LaTeX

You have to explicitly select the minted environment when running ptex2tex to get pygmentized computer code in LaTeX:

Terminal> doconce ptex2tex mydoc envir=minted
Terminal> pdflatex -shell-escape mydoc

LaTeX error because of underscores

LaTeX requires prefixing underscores by a backslash. Either typeset words with underscores in inline verbatim text (so you do not need the backslash) or use the preprocessor to insert LaTeX-specific text with a backslash, e.g.,

Here is a word underscore:
%% if FORMAT in ('latex', 'pdflatex'):
%% else
%% endif

Usually, inline verbatim text is way to go with underscores anyway.

LaTeX does not like underscores in URLs

Suppose you have a URL reference like

..which can be found in the file "my_file.txt":

LaTeX will stop with a message about a missing dollar sign. The reason is that underscores in link texts need to be preceded by a backslash. However, this is incovenient to do in the DocOnce source since the underscore is misleading in other formats. The remedy is to format the link text with inline verbatim tags (backticks):

..which can be found in the file "`my_file.txt`":

Verbatim text in links works fine with underscores.

Inline verbatim fails in admon headings

A known problem is to have the word


in (admon) headings. Otherwise inline verbatim should work, both in section headings and admon headings.

How can I customize the look of an admonition?

The default environment, --latex_admon=mdfbox, has many options for customization. Say we want the notice environment to have a very small font, no background color, no line below the title, no visible frame, and a smaller width. All this is a matter of editing the variables in the newmdenv command that defines the notice_mdfboxmdframed environment in the .tex file.

The simplest approach is to make a script that automatically edits some of the variables in newmdenv environments:

# Edits for mdframed environments
doconce format pdflatex $name --latex_code_style=vrb
doconce subst '  backgroundcolor=.+' \
        '  backgroundcolor=white,' $name.tex
doconce subst '  frametitlebackgroundcolor=.+' \
        '  frametitlebackgroundcolor=white,' $name.tex
doconce subst '  leftmargin=.+' '  leftmargin=3cm,' $name.tex
doconce subst '  rightmargin=.+' \
        '  rightmargin=3cm,\n  font=\\tiny,' $name.tex
doconce subst '  frametitlerule=.+' \
        '  frametitlerule=false,' $name.tex
doconce subst '  linewidth=.+' '  linewidth=0pt,' $name.tex
# Edits for fontsize in Verbatim
doconce replace ',fontsize=\fontsize{9pt}{9pt}' \
        ',fontsize=\fontsize{6pt}{6pt}' $name.tex

Note that these edits actually apply to all types of admonitions! More tailored edits must include the text of the entire environment definition.

Here is a possible test file:

======= Heading =======


!bnotice Long box
% for i in range(10):
bla-bla, bla-bla, bla-bla, bla-bla, bla-bla, bla-bla, bla-bla,
% endfor

x &\in [0,1]\\
y &= sin(x)

!bc pycod
def myfuncf(x):
    return sin(x)

% for i in range(100):
bla-bla, bla-bla, bla-bla, bla-bla, bla-bla, bla-bla, bla-bla,
% endfor

A (much) better approach is to define a user-defined environment, called (e.g.) minipage, see the manual. This environment has begin tag !bu-minipage and end tag !eu-minipage. The environment is defined in a file in the same directory as the DocOnce source file. An example is given in this file.

How can I have unnumbered sections?

Use the --section_numbering=off option:

Terminal> doconce format pdflatex mydoc --section_numbering=off

LaTeX suddenly places figures differently

Until August 25, 2015, the figure environment applied the [t] (top) option, but since then the [h] option is used. Of even greater influence are the topfraction, bottomfraction, and textfraction parameters in the .tex file. See the “Figures” section in the manual for more information and how to customize the placement of figures.

I want figure references with page number too

A DocOnce user wanted figure references to be as follows in LaTeX:

% if current page is different from figure page:
... Figure \ref{my:fig} on page \pageref{my:fig}.
% if current page is the same as the figure page:
... Figure \ref{my:fig}.

All other formats should emit the standard treatment of a DocOnce figure reference with ref.

Quick solution with the varioref package

DocOnce actually generates such references in LaTeX output if you request the varioref package: --latex_packages=varioref (the standard ref command is now replaced by \vref, except in equation references).

Manual solution (or a good example on what Mako can do)

Here is an implementation using if-else tests in LaTeX and internal variables. Unfortunately, this solution is not reliable because it uses the \thepage variable in LaTeX (for the page number of the current page) and this variable is unreliable. The solution above (using \vref and the varioref package) is much better. However, the manual solution is a good example on how to use Mako to do seemingly complicated things.

The above problem can be solved by some Mako programming and usage of the LaTeX packages ifthen and refcount.

def figref(label):
    text = 'Figure ref{%s}' % label
    if FORMAT in ('latex', 'pdflatex'):
    text += r'\ifthenelse{\equal{\thepage}{\getpagerefnumber{%s}}}{}{ on page \pageref{%s}}' % (label, label)
    return text

FIGURE: [myfigfile, width=600 frac=0.8] My figure. label{my:fig}

We refer to ${figref('my:fig')}.

# Much later
..., as seen in ${figref('my:fig')}.

The first reference is on the same page as the figure, and LaTeX should not write the page number, while the second reference is on another page so both the figure number and the page number should appear in the output. All other formats have a standard figure reference (translated to a figure number in HTML and to the caption in Sphinx).

The LaTeX output is something like this:

\begin{figure}[h] % my:fig1
  My figure. \label{my:fig1}
%\clearpage % flush figures sec:fig

We refer to Figure~\ref{my:fig1}\ifthenelse{
\equal{\thepage}{\getpagerefnumber{my:fig}}}{}{ on page \pageref{my:fig1}}.

% Much later
..., as seen in Figure~\ref{my:fig1}\ifthenelse{
\equal{\thepage}{\getpagerefnumber{my:fig}}}{}{ on page \pageref{my:fig1}}.

Error when running latex: You must have ‘pygmentize’ installed

This message points to the use of the minted style for typesetting verbatim code. You need to include the -shell-escape command-line argument when running latex or pdflatex:

Terminal> latex -shell-escape file mydoc.tex
Terminal> pdflatex -shell-escape file mydoc.tex

Using doconce ptex2tex will turn on the minted style if specified as environment on the command line, while using ptex2tex requires the preprocessor option -DMINTED to turn on the minted package. When this package is included, latex or pdflatex runs the pygmentize program and the shell-escape option is required.

Why are the LaTeX section headings smaller than normal?

DocOnce inserts a special command to make the headings more compact:


as explained in the titlesec package documentation. To retrieve the standard LaTeX headings, comment out this line or remove it:

Terminal> doconce format pdflatex mydoc
Terminal> doconce subst '\\usepack.+\{titlesec\} '' mydoc.p.tex

You can easily make the headings even smaller than the normal font by replacing [compact] by [compact,small] as parameter specification for titlesec.

I get LaTeX compilation errors about “shadedquoteBlue” in code blocks in exercises

When using colored boxes for code in LaTeX, a code snippet is needed in the ordinary running text before code snippets inside exercises, problems, or projects. This is a kind of bug in DocOnce that is challenging to fix. It is usually only a problem when writing documents mainly containing exercises, problems, or projects.

I get compilation error due to pause commands

The |\pause| commands are intended for popping up code segments in slides. If you compile the document without having run doconce slides_beamer first, standard LaTeX have a problem with |\pause|. The remedy is to just remove these commands by

Terminal> doconce subst '\|\\pause\|\n' '' mydoc.tex

before running pdflatex mydoc.

The cell structure in slides does not work for me ...

Common errors:

  • Empty cells? No cell can be empty. Just insert a comment # Empty cell to make it non-empty.
  • Wrong numbering of the cells. They go 00, 01, 02, 10, 11, etc.

Also, text outside the slidecell boxes are not shown in the slide. Everything you want to see must be inside the cells. Use <linebreak> repeatedly to insert vertical spacings inside cells.

Can I have LaTeX figures with shadows?

This is easy by including the fancybox and graphicx packages and wrapping all \includegraphics in a shadow box:

Terminal> doconce format pdflatex mydoc
Terminal> doconce replace \
          'microtype}', 'microtype,fancybox,graphicx}' mydoc.p.tex
Terminal> doconce subst '(\\includegraphics\[.+\}\})' \
          '\\shadowbox{\g<1>}' mydoc.p.tex

How can I use my fancy LaTeX environments?

See the section Example: Defining a Theorem Environment in the DocOnce manual for how to make a custom theorem environment also in DocOnce, without using implementations restricted to LaTeX. See also the section How can I make use of a native LaTeX environments (example environment for instance)?.

The LaTeX file does not compile

If the problem is undefined control sequence involving


the cause is usually a verbatim inline text (in back-ticks in the DocOnce file) spans more than one line. Make sure, in the DocOnce source, that all inline verbatim text appears on the same line.

The LaTeX Beamer file does not compile

Make sure you have a !split before every slide heading.

Inline verbatim gives error

Check if the inline verbatim contains typical LaTeX commands, e.g.,

some text with `\usepackage{mypack}` is difficult because
ptex2tex will replace this by \code{\usepackage{mypack}} and
then replace this by
which is wrong because ptex2tex applies regex that don't
capture the second }

The remedy is to place verbatim LaTeX commands in verbatim blocks - that is safe.

Errors in figure captions

Such errors typically arise from unbalanced curly braces, or dollar signs around math, and similar LaTeX syntax errors.

(Note that verbatim font is likely to cause trouble inside figure captions, but DocOnce will automatically replace verbatim text in back-ticks by a proper texttt command (since verbatim font constructions does not work inside figure captions) and precede underscores by backslash.)

I want to tune the top (preamble) of the LaTeX file

It is easy to provide a customized preamble text:

Terminal> doconce format latex mydoc --latex_preamble=mytop.tex

If mytop.tex starts with a documentclass specification, the whole file becomes the complete preamble in mydoc.p.tex, otherwise mytop.tex is added at the end of the preamble generated by DocOnce.

If you already have some preamble that defines styles etc., I recommend to generate a .tex file from DocOnce and merge the preamble you have with the one generated by DocOnce. When the .tex file compiles with the desired preamble, store it in a separate file and use it with the --latex_preamble= option. (This approach will for fix the preamble for the future so updates of the DocOnce-generated preamble will not be available for this document.)

Note also that doconce replace and doconce subst can be used after doconce format to tune the LaTeX code in the preamble (and elsewhere). Such automatic edits are useful if they are few.

There are comment lines with

--- begin preamble ---


--- end preamble ---

in the generated .tex file that can be used to replace the whole preamble by another text via a script.

How can I control the placement of figures?

In general, LaTeX will control the placement, and DocOnce applies (for now) the [t] option to recommend figures to be placed at the top of a page. This can be changed in different ways, using techniques from the sections How do I get “Figure” written in another language? and I want to tune the top (preamble) of the LaTeX file. The float package and the [H] (“here”) option for figures makes figures appear closer to their original location:


The [t] option in figures must be removed:

doconce replace '{figure}[t]' '{figure}' mydoc.tex

Custom preamble file. Place the lines above in a file mypreamble.tex and ask DocOnce to add this file to the preamble: --latex_preamble=mypreamble.tex.

Edit the .tex file. There is a special line in the .tex file,

%% insert custom LaTeX commands...

which can be used to insert desired commands, in this case by

doconce subst '% insert custom LaTeX.+' '\\usepackage{float}\n\floatplacement{figure}{H}' mydoc.tex

Note that you in both cases need to run the doconce replace above command to remove the [t] option.

How can I get a two-column text?

Simply add twocolum to the \documentclass command. If the mydoc.tex file looks like


you can do a simple substitution edit

Terminal> doconce subst 'twoside,' 'twocolumn,\ntwoside,' mydoc.tex

Solution heading in exercise solutions appear after the solution content

Sometimes a solution environment with code

!bc cod
def f(x):
    return x + 2

leads to strange behavior with verbatim LaTeX environment: the Solution heading appears after the code in the solution. This appears to be a LaTeX problem since the generated LaTeX code has the heading and solution content in the right order. A working remedy is to insert a text before the code:

!bc cod
def f(x):
    return x + 2

Subexercises (subex{a)}) triggers “Missing number, treated as zero”

Check if you have done a doconce subst of section to section*. Such a substitution will alter the newcommand \subex defined in the .tex file and insert an erroneous \@startsection*, which should not contain the *. Be more specific with the substitution of section in the .tex file:

doconce subst '\\section\{' '\\section*{' mydoc.tex
doconce subst '\\subsection\{' '\\subsection*{' mydoc.tex
# or
doconce replace '\section{' '\section*{' mydoc.tex
doconce replace '\subsection{' '\subsection*{' mydoc.tex

Exercises in the Springer_sv style looks strange

The Springer_sv style demands exercises to appear within the prob environment, and the svmono.cls package typesets prob with small headlines.

How to typeset papers with specified style files?

DocOnce has the --latex_style= option for specifying a few LaTeX styles for papers and books. This option mostly support book styles, since traditionally, paper styles in various journals often have special commands for authors, institutions, summary, and so on that are cumbersome to support through DocOnce. It was often easier to develop the paper in DocOnce and at submission time, manually edit the LaTeX output to fit a particular journal style. (SIAM and Elsevier journal have had direct support in DocOnce, though.)

With open access publishing it makes more sense to maintain a paper in DocOnce and publish derived and future versions in various electronic formats. How to then, at some stage in the process, make a special LaTeX version according to a journal’s style?

The simplest approach is probably to develop a compilation script that performs a set of edits through doconce replace and doconce subst commands that turn standard DocOnce LaTeX output into the text required for a special journal style. Usually, such edits are about adding packages, maybe some special commands, and replacing perhaps title, author, date, and summary commands. Below is a sketch how that can be done for PLOS journals. These journals offer a LaTeX template demonstrating appropriate commands. Some text is needed in the preamble, and we can insert that text at the place marked for user-specific extensions (“insert custom LaTeX commands...”).


# Compile to latex output mydoc.tex
doconce format pdflatex $name --latex_bibstyle=plos2015 --latex_code_style=vrb

# Edit mydoc.tex file
doconce subst '% insert custom LaTeX commands...' '
% Text layout
\textwidth 5.25in
\textheight 8.75in
% Remove brackets from numbering in List of References
\usepackage[top=0.85in,left=2.75in,footskip=0.75in]{geometry}' $name.tex

# Compile the usual way
pdflatex $name

This example hopefully gives some ideas how to create specialized LaTeX output from DocOnce documents. If the journal style employs special LaTeX environments, see the section How can I make use of a native LaTeX environments (example environment for instance)? how to utilize these from DocOnce.

I want exercises to have small headings (not subsections)

By default, DocOnce typesets exercises as subsections in LaTeX. However, the heading is defined by a newcommand exercisesection (right after \begin{document}) so it is easy to switch to any tailored heading. For example, we can use a paragraph heading:

Terminal> doconce subst \
          '\{exercisesection\}\[1\]\{\\subsection\*' \
      '{exercisesection}[1]{\paragraph' mydoc.tex

This typesetting is perhaps more suitable if you have exercises scattered around in the document rather than grouped in sections.


===== Strange nested lists in gwiki

DocOnce cannot handle nested lists correctly in the gwiki format. Use nonnested lists or edit the .gwiki file directly.

Lists in gwiki look ugly in the gwiki source

Because the Google Code wiki format requires all text of a list item to be on one line, DocOnce simply concatenates lines in that format, and because of the indentation in the original DocOnce text, the gwiki output looks somewhat ugly. The good thing is that this gwiki source is seldom to be looked at - it is the DocOnce source that one edits further.


How can I add a search facility to an HTML document?

There are many services for this. FreeFind is an easy-to-use service that gives you some HTML code to include in the document, typically inside a # #if FORMAT == "html" and # #endif block.

MathJax formulas are not properly rendered

Here are some common problems:

  • Two equations cannot have identical label (this error often arises from copying and pasting equations).
  • [ and ] brackets must sometimes be replaced by \lbrack and \rbrack.
  • Inline mathematics cannot have a space after the first dollar sign.
  • Equation environments must be \[ ...\], equation, equation*, align, or align* - avoid all other types of environments (split, alignat, and whatever).
  • Errors in formulas that LaTeX accepts may still lead to unrendered formulas in MathJax.

If the corresponding LaTeX-based PDF output has the correct formula, one must try to rewrite the LaTeX mathematics so MathJax accepts it. MathJax can only handle a subset of what is legal mathematics in LaTeX.

Even if HTML is your target output format, it is strongly recommended to develop the mathematics with pdflatex as output to debug formulas before you try to render them in MathJax.

How can I change the layout of the HTML page?

Autoedits of the .html file

The easiest way is to edit the HTML style or the HTML code directly. However, those edits are overwritten the next time you compile the DocOnce document to HTML. The edits should therefore be automated using the doconce subst (for regular expression editing) or doconce replace (for plain text substitution editing) commands in the file where you run doconce format html mydoc. For example, say you want narrower gray admonition boxes with a much thicker boundary. The .alert style must then be changed, more precisely the border and the width specification. You can then add these statements after running doconce format html ...:

doconce replace 'border:1px' 'border:11px' mydoc.html
doconce replace 'width: 75%;' 'width: 35%' mydoc.html

Specify a .css file

Another way to control the layout is to copy the style in the HTML file into a .css file, edit that file as you like, and provide the file as part of the compilation using the --css=mystyle.css flag. For example, say you want to transform the headings to something attractive for young girls (white text on pink background). A .css file can be written from scratch, but one can also generate one from one of the built-in DocOnce HTML styles by running

Terminal> doconce format html mydoc --css=pink.css \

The result is a new file pink.css containing the specification of the blueish style. One can now change this pink.css file to h1 headings with pink background and white text, h2 and h3 headings with pink text, and pink color for visited or hovered hyperlinks:

h1 {
    font-family:"comic sans ms";
    width: 900px;
    font-size: 48px;
    text-align: center;
    background: #EA00FF; /* pink */
    border-style: solid;
    border-width: 5px;
    border-color: #FFFFFF;
    padding: 20px;
    margin: 20px;
    margin-left: 10px;
    color: white
h2, h3 {
    font-family:"comic sans ms";
    font-size: 18px;
    color: #EA00FF;
h3 { font-size: 24px; }
a { color: #1e36ce; text-decoration:none; }
a:hover, a:visited { color: #EA00FF; /* pink */ }

The rest of the file can remain unaltered. Running

Terminal> doconce format html mydoc --css=pink.css \

will now render mydoc.html with pink headings and visited links.

Specify a template

The standard of way of completely controlling the HTML format is to use an HTML template. The DocOnce source is then the body of text (leave out TITLE: to get HTML without a header and footer). The --html_template=filename command-line option will then embed the DocOnce text in the specified template file, where you can use style sheets and desired constructs in the header and footer. The template can have “slots” for a title (%(title)s), a date (%(date)s), and the main body of text (%(main)s). For typesetting code, pygments is used (if installed) and can be turned off by --no_pygments_html (leaving code in gray boxes).

The easiest way is to get fancy layouts in HTML is to use the sphinx format and one its many themes.

Why do figures look ugly when using HTML templates?

The HTML header that DocOnce generates contain special styles for figure captions and the horizontal rule above figures. When using templates these styles are not defined, resulting in a rule that spans the width and a centered caption. Changing the appearance of the rule and caption can either be done by inserting styles or simply by automatic editing of the HTML code in a little shell script:

doconce replace '<p class="caption">' \
 '<p style="width: 50%; font-style: italic; color: blue">' mydoc.html
doconce replace '<hr class="figure">' \
 '<hr style="width:60%, font-style: normal">' mydoc.html

reveal/deck HTML5 slides

Python Online Tutor code does not work in reveal

Use the Chrome browser (the code does not work in Firefox in combination with reveal HTML5, but it works in plain HTML).

Reveal slides are stacked on top of each other

This problem can be caused by having a !bblock environment crossing two slides because of a forgotten !eblock on the first slide. To locate the problematic slides, copy chunks of slides to a new file, compile, and inspect. This will reveal the problematic chunk.

Reveal slides are moving steadily to the left

This seems to be a problem when one has used the mouse to scroll down on a slide and continue to use the right arrow for moving to the next slide. Click on the arrow in the slide instead of using the arrow key.

YouTube movies do not work

They do not work in reveal or deck unless the Chrome browser is used. Usually the HTML5 slides work best in Firefox.

Online Python Tutor does not work

  • Check that there are no syntax errors in the code by running the code as an ordinary file. Syntax errors lead to empty space and no tutor in HTML output.
  • Seems to be a problem with reveal slides. The Forward button is not clickable.