If a document contains more than one type of source code then the source mode may be changed dynamically as the document is processed. All QuickBook documents are initially in C++ mode by default, though an alternative initial value may be set in the Document section.

To change the source mode, use the [source-mode] markup, where source-mode is one of the supported modes. For example, this:

Python's [python] `import` is rather like C++'s [c++] `#include`. A
C++ comment `// looks like this` whereas a Python comment [python]
`# looks like this`.

will generate:

Python's import is rather like C++'s #include. A C++ comment // looks like this whereas a Python comment #looks like this.

Quickbook 1.7 introduced the ! element which can be used to set the source mode of the following element:

[teletype]
Example in C++: [!c++] `int main() {}`,
example with no highlighting: `int main() {}`.

will generate:

Example in C++: int main() {}, example with no highlighting: int main() {}.

In order to change the source mode for a whole paragraph, put the ! element on a separate line before the paragraph:

[!c++]
`int main() {}` is highlighted as C++, as is `//example`.

[!c++] `int main() {}` is also highlighted as C++,
but `//example` isn't.

generates:

int main() {} is highlighted as C++, as is //example.

int main() {} is also highlighted as C++, but //example isn't.

The ! element can also be used to set the source mode for blocks and sections. For example:

[!python]
[section:python Section in which all code samples use python]

[/...]

[endsect:python]

[!c++]
[section:cpp Section in which all code samples use C++]

[/...]

[endsect:cpp]

Or to set the source mode for a table:

[!teletype]
[table
    [[code][meaning]]
    [[`+`][addition]]
]

	Note
	The source mode strings are lowercase.