Difference between revisions of "Delimiter"

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(Filled in some details and examples.)
 
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=Line delimiters=
+
== Delimeters and breaks ==
 +
Under ordinary circumstances, you don’t need to tell ConTeXt how to group text or where to break lines and pages. ConTeXt handles such things automatically.
  
 +
However, there are times when you do need to specify these things manually because ConTeXt's default handling isn't what you want. For this, you can include explicit delimiters and breaks to get just the effect you’re after. For example, you might want to:
 +
 +
* have ConTeXt treat some text as a single unit
 +
* tell ConTeXt where to break lines
 +
* tell ConTeXt where to break pages
 +
 +
We'll look at each of these in turn.
 +
 +
== Treating text as a single unit ==
 +
To treat text as a single unit, enclose it in { }. Here are three examples of why and how to do this.
 +
 +
=== Limiting the scope of a switch ===
 +
To limit the scope of a switch, enclose the text that it should act on in { }. For example:
 +
 +
<context source="yes" text="produces">
 +
The quick {\em brown} fox jumped.
 +
</context>
 +
 +
=== Commands that operate on single units ===
 +
To use a command that operates on the next single unit, enclose the text that it should operate on in { }. For example:
 +
 +
<context source="yes" text="produces">
 +
The quick \framed{brown} fox jumped.
 +
</context>
 +
 +
=== Using [ ] in command arguments ===
 +
To delimit a command argument's value that includes [ ], enclose the value in { }. For example:
 +
 +
<context source="yes" text="produces">
 +
% This doesn't work properly:
 +
\section[title=The list element a[3]]
 +
 +
% This works properly:
 +
\section[title={The list element a[3]}]
 +
</context>
 +
 +
 +
== Line breaks ==
 +
There are lots of ways to help ConTeXt decide where to break lines.
 +
 +
If you want to force a line break at a certain point no matter what, and you don't want ConTeXt to justify the truncated line, use {{cmd|crlf}} or {{cmd|\}}:
 +
 +
<context source="yes" text="produces">
 +
The quick brown fox jumped over the lazy dog. The quick\crlf brown fox jumped over the lazy dog.
 +
 +
The quick brown fox jumped over the lazy dog. The quick\\ brown fox jumped over the lazy dog.
 +
</context>
 +
 +
If you would like to tell ConTeXt that this ''might'' be a good place for a line break, you can use
 +
 +
If you would like a line break to happen whenever you put one in the code (for example, when you are typesetting verse), use {{cmd|startlines}} {{cmd|stoplines}}. For example:
 +
 +
<context source="yes" text="produces">
 +
The quick brown fox
 +
Jumped over the
 +
Very lazy
 +
Dog.
 +
 +
\startlines
 +
The quick brown fox
 +
Jumped over the
 +
Very lazy
 +
Dog.
 +
\stoplines
 +
</context>
 +
 +
If you would like to allow ConTeXt to hyphenate a word at a certain place to make a line break, if ConTeXt determines that a line break is suitable there, use {{code|\-}}. For example, to suggest a rather nonstandard hyphenation:
 +
 +
<context source="yes" text="produces">
 +
The quick brown fox jumped over the lazy dog. A quick brown fox jumps serendipitously over the lazy dog.
 +
 +
The quick brown fox jumped over the la\-zy dog. A quick brown fox jumps serendi\-pitously over the la\-zy dog.
 +
</context>
 +
 +
If you want to set up a hyphenation pattern for a word throughout your document, you can use {{cmd|hyphenation}}. For example (again , this is ''not'' a standard hyphenation, but it illustrates the method):
 +
 +
<context source="yes" text="produces">
 +
\hyphenation{la-zy, ser-endi-pit-ous-ly}
 +
The quick brown fox jumped over the lazy dog. A quick brown fox jumps serendipitously over the lazy dog.
 +
 +
The quick brown fox jumped over the lazy dog. A quick brown fox jumps serendipitously over the lazy dog.
 +
</context>
 +
 +
 +
 +
 +
<!--
 +
Previous code, removed 2020-10-20
 
*Forced linebreak (in flowtext broken line is NOT jusify-aligned): \crlf
 
*Forced linebreak (in flowtext broken line is NOT jusify-aligned): \crlf
 
*Forced linebreak (but disapears in the ToC, in flowtext justify-alignment also in the broken line): \\
 
*Forced linebreak (but disapears in the ToC, in flowtext justify-alignment also in the broken line): \\
Line 8: Line 97:
  
 
*Default behavior for | |: {{cmd|setuphyphenmark}}
 
*Default behavior for | |: {{cmd|setuphyphenmark}}
 +
-->
  
−
=Page delimiters=
+
== Page breaks ==
 +
The command to help ConTeXt choose where to put a page break is {{cmd|pagebreak}}. This has many options, but if you simply want to force a page break at a certain place, use {{cmd|pagebreak|[yes]}}. And as you might guess, to tell ConTeXt to try to avoid a page break at a certain place, use {{cmd|pagebreak|[no]}}. There are many more options to this command, so see the command page {{cmd|pagebreak}} for further details.
  
−
{{cmd|page}}
+
If you want to keep a certain section of text together, you can use {{cmd|testpage}}. This command takes the number of lines that you are testing for as its argument. If there are not ''n'' lines available, a page break will be inserted at the location of the {{cmd|testpage}} command. For example, if the quotation from {{code|\input knuth}} takes up 10 lines of text in your document and you want to keep the whole quotation on a single page, you could use
  
−
=Check for available space on the page=
+
<texcode>
 +
\testpage[10]
 +
\input knuth
 +
</texcode>
 +
If there are at least 10 lines left on the page, ConTeXt will not insert a page break, so the Knuth quotation will go on the current page. If there are fewer than 10 lines left on the page, ConTeXt will insert a page break, and the Knuth quotation will go on the next page.
  
−
If you have a certain run of text that you want to keep together, you can test for the number of lines available on the current page with {{cmd|testpage|[''n'']}}, where ''n'' is the number of lines required.  If there are not ''n'' lines available, a page break will be inserted at the location of the {{cmd|testpage}} command.
 
  
 
[[Category:Basics]]
 
[[Category:Basics]]

Latest revision as of 16:36, 20 October 2020

Delimeters and breaks

Under ordinary circumstances, you don’t need to tell ConTeXt how to group text or where to break lines and pages. ConTeXt handles such things automatically.

However, there are times when you do need to specify these things manually because ConTeXt's default handling isn't what you want. For this, you can include explicit delimiters and breaks to get just the effect you’re after. For example, you might want to:

  • have ConTeXt treat some text as a single unit
  • tell ConTeXt where to break lines
  • tell ConTeXt where to break pages

We'll look at each of these in turn.

Treating text as a single unit

To treat text as a single unit, enclose it in { }. Here are three examples of why and how to do this.

Limiting the scope of a switch

To limit the scope of a switch, enclose the text that it should act on in { }. For example: 

The quick {\em brown} fox jumped.

produces

Commands that operate on single units

To use a command that operates on the next single unit, enclose the text that it should operate on in { }. For example: 

The quick \framed{brown} fox jumped.

produces

Using [ ] in command arguments

To delimit a command argument's value that includes [ ], enclose the value in { }. For example: 

% This doesn't work properly:
\section[title=The list element a[3]]

% This works properly:
\section[title={The list element a[3]}]

produces


Line breaks

There are lots of ways to help ConTeXt decide where to break lines.

If you want to force a line break at a certain point no matter what, and you don't want ConTeXt to justify the truncated line, use \crlf or \\: 

The quick brown fox jumped over the lazy dog. The quick\crlf brown fox jumped over the lazy dog.

The quick brown fox jumped over the lazy dog. The quick\\ brown fox jumped over the lazy dog.

produces

If you would like to tell ConTeXt that this might be a good place for a line break, you can use

If you would like a line break to happen whenever you put one in the code (for example, when you are typesetting verse), use \startlines \stoplines. For example: 

The quick brown fox
Jumped over the
Very lazy
Dog.

\startlines
The quick brown fox
Jumped over the
Very lazy
Dog.
\stoplines

produces

If you would like to allow ConTeXt to hyphenate a word at a certain place to make a line break, if ConTeXt determines that a line break is suitable there, use \-. For example, to suggest a rather nonstandard hyphenation: 

The quick brown fox jumped over the lazy dog. A quick brown fox jumps serendipitously over the lazy dog.

The quick brown fox jumped over the la\-zy dog. A quick brown fox jumps serendi\-pitously over the la\-zy dog.

produces

If you want to set up a hyphenation pattern for a word throughout your document, you can use \hyphenation. For example (again , this is not a standard hyphenation, but it illustrates the method): 

\hyphenation{la-zy, ser-endi-pit-ous-ly}
The quick brown fox jumped over the lazy dog. A quick brown fox jumps serendipitously over the lazy dog.

The quick brown fox jumped over the lazy dog. A quick brown fox jumps serendipitously over the lazy dog.

produces



Page breaks

The command to help ConTeXt choose where to put a page break is \pagebreak. This has many options, but if you simply want to force a page break at a certain place, use \pagebreak[yes]. And as you might guess, to tell ConTeXt to try to avoid a page break at a certain place, use \pagebreak[no]. There are many more options to this command, so see the command page \pagebreak for further details.

If you want to keep a certain section of text together, you can use \testpage. This command takes the number of lines that you are testing for as its argument. If there are not n lines available, a page break will be inserted at the location of the \testpage command. For example, if the quotation from \input knuth takes up 10 lines of text in your document and you want to keep the whole quotation on a single page, you could use 

\testpage[10]
\input knuth

If there are at least 10 lines left on the page, ConTeXt will not insert a page break, so the Knuth quotation will go on the current page. If there are fewer than 10 lines left on the page, ConTeXt will insert a page break, and the Knuth quotation will go on the next page.

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