Changes

{{note | I am replacing this article with a detailed article that I am writing for TugBoat. For the time being I am leaving the original article at the end. Fell free to make any changes or to merge the examples of the original article. --[[User:Adityam|Aditya]]}} Many-a-timesVery often, you want to to generate multiple versions of the same document.:One one version for printing and one for viewing on the screen; , one version forstudents and one version for the instructor; , and so on. You can do this in asimple but naive way. Create : create different files with setup set up for the different versions and

could use '''<em>modes'''</em>&mdash;the ConTeXt way of doing conditional processing. 

A mode is similar to a conditional flag, but with a few advantages. New : new modes

multiple modes can be simultaneously enabled or disabled, and the status of multiple

switch. SoAs a result, multiple versions of a document can be generated without changing

* <code><cmd>enablemode</cmd> [...]</code>

The names are self explanatory-descriptive. <cmd>enablemode</cmd> activates a mode,

example, you can activate modes named <ttcode>screen</ttcode> and <ttcode>solution</ttcode> modes bywith

\enablemode[screen,solution]

<code>texexec</code> and or <code>context</code>. For example, another way to activate the <ttcode>screen</ttcode> and<ttcode>solution</ttcode> modes, you can to run ConTeXt usingone of:

texexec --mode=screen,solution ... context --mode=screen,solution ...

To get different pdf output for different = Conditional processing based on modes, you can add <code>--result</code> switch=

context --You may want to process or ignore a chunk of code if a particular mode=screen,solution --result=solutionis enabledor disabled.pdf Such a chunk of code is specified using <code>\startmode</code> and<code>\startnotmode</code> environments.Their usable is best explained by an example.. = Conditional processing based on modes =

is for print or screen. This can be done in multiple ways. You could either seta the default paper size for print and change it for in screenmode:

\setuppapersize[letter][letter]  \startmode[screen] \setuppapersize[S6][S6] \stopmode

4:3 aspect ratio and a width equal to the width of A4 paper.)  Alternatively, youcould set a default paper size for the screen and change it if the screen mode is

\setuppapersize[S6][S6]  \startnotmode[screen] \setuppapersize[letter][letter] \stopnotmode

<cmdcode>\startmode</cmdcode> and <cmdcode>\startnotmode</cmdcode> can check for multiple modes. The,arguments to <cmd>startmode</cmd> and <cmd>startnotmode</cmd> can be by giving a list of modesas their arguments. <cmdcode>\startmode</cmdcode> processes its contents (everything until the next<cmdcode>\stopmode</cmdcode> which means that , thus <cmdcode>\startmode</cmdcode> cannot be nested.) if any of the modes are enabled, otherwise (i.e., when all the modes aredisabled) <cmdcode>\startmode</cmdcode> ignores it itscontents. The opposite is <cmdcode>\startnotmode</cmdcode> is theopposite. It : it processes its contents (everything until the next<cmdcode>\stopnotmode</cmdcode> ) if any of the modes are disabled, otherwise (i.e., &mdash;when allthe mods modes are enabled) <cmd>startnotmode</cmd> ignores its &mdash;the contentsare ignored.

<cmdcode>\startmode</cmdcode> and <cmdcode>\startnotmode</cmdcode> are "<em>or</em> " environments. They

"<em>and</em> " counterparts are also available: <cmdcode>\startallmodes</cmdcode> and <cmdcode>\startnotallmodes</cmdcode>,which process their contents only if all the given modes satisfy the requiredcondition. For example, suppose you want to enable interaction (e.g., hyperlinks) etc.only when both <ttcode>screen</ttcode> and <ttcode>solution</ttcode> modes are enabled. Then you can

\startallmodes[screen,solution] \setupinteraction[state=start] \stopallmodes

% Process Processed if one any of the modes is enabled

% Process Processed if one any of the modes is disabled

% Process Processed if all the modes are enabled

% Process Processed if all the modes are disabled

These environments have a <code>\doif...</code> alternative alternatives that are useful for shortsetups and . Also, they can also be nested.

\noindentation The logic for determining when the content is processes processed is exactly the same asfor the <code>start</code>-<code>stop</code> alternativescommands.

These <code>\doif</code> commands each have a variant that can to process something else alternative code if

\doifmodeelse {modes} {content} {alternativealt}\doifnotmodeelse {modes} {content} {alternativealt}\doifallmodeselse {modes} {content} {alternativealt}\doifnotallmodeselse {modes} {content} {alternativealt}

In addition to Besides allowing user-defined definable modes, ConTeXt provides some system modes. Thesemodes start with a <code>*</code>character. Here I will explainonly explain the more commonly usedsystem modes. You can ; see the ConTeXt [http://pragma-ade.com/general/manuals/mmodes.pdf modes manual]for a complete list of system modes.

determine whether MkII MKII or MkIV MKIV is being used. These modes are handy when youwant different setups for MkII MKII and MkIVMKIV.

A document must be run multiple times to get the cross referencing, table of contents, etc.\right. However, sometimes you need to do some external processing (like e.g., graphicconversion) that only needs to be done only once. In such cases, the<code>*first</code> mode is handy, which checks for &mdash;it is active only on the first run of the document.

for detailsof this approach. Both A product and or its components can may be compiled separately. Sometimes , and you may want to process do something different when a component differently depending on whether it product isbeing compiled directly, or if the complete product when a component is being compiled. This canTo do so, you need to check forbe checked using the modes <code>*project</code>, <code>*product</code>, <code>*component</code>,andand <code>*environment</code>; these modes are set when the corresponding structure fileis processed. For example, the <code>*product</code> mode is set whenever aproduct file is read (; more specifically, whenever a when <code>\startproduct</code> isencountered). Similarly, a mode <code>*text</code> is enabled whenever awhen<code>\starttext</code> is encountered, and likewise for the others.

A large document is also typically broken down into different section blocks like:

blocks are refered referred to as <code>frontpart</code>, <code>backpartbodypart</code>, <code>appendix</code>, and<code>backmatterbackpart</code>. Each section block sets a system mode with the same name. So,if you want macros that work differently for in different section blocks, you cancheck for modes <code>*fronpart</code>, <code>*backpartfrontpart</code>, <code>*appendixbodypart</code>, and<code>*backmatter</code> modesso on.

ConTeXt provides support for multiple languagelanguages. Language Languages are recognized bytheir IETF language tags, like <code>en-us</code> for US English, <code>en-gb</code>

has a main language , set using with the command <code>\mainlanguage[...]</code> ,that is sued used for

Whenever a language is chosen, its id identifier is set as a mode. The mode for the mainlanguage starts with two <code>*</code>. For example, when the main language is US

Other system modes are: <code>*figure</code> which is set when a graphic is found,<code>*interaction</code> which is set when interaction is enabled, <code>*grid</code> whichis set when grid typesetting is enabled, and <code>*pdf</code> and <code>*dvi</code> whichare set depending on when the whether we are generating pdf output is PDF or dvi outputDVI. Othersare too esoteric to desribe describe here. If you are interested, see the [http://pragma-ade.com/general/manuals/mmodes.pdf modes manual]mentioned earlier.

= Earlier Article Specific Examples = Often you'd like to publish different versions of a document, say a presentation and a handout or a student's and a teacher's version.

<texcode>ConTeXt is Suppose you want to generate two versions of a great TeX macro packagedocument, one with times font and one with palatino.\startmode[handout] % The following text will only appear in the handoutIt’s based on Plain TeX like the better known LaTeX.\stopmode</texcode>One way to do this is as follows:

And run with one of the following:<pre> texexec --pdf --mode=palatino filename texexec --pdf --mode=times filename</pre>

If you want to enable some mode(s) without changing the command line (e.g. because you use some TeX GUI), you can use<cmd>enablemode</cmd><tt>[mymode]</tt> in your source. Put this before you load your environment! You can even enable several modes at once like <tt>[a4,print]</tt>. == First-run-mode: Doing things only Running external commands once == When you need to call external programs to process some of your data and return you some results, you probaly want to do that only once (instead of three times, if ConTeXt needs three runs). Here's how you can do it:

\doifmode{startmode[*first}{%] % external program which creates a file figure1fig-1.ps

\executesystemcommand{texmfstart pstopdf figure1fig-1.ps}}\stopmode

\externalfigure[figure1fig-1]