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Documentation
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Expression Functions
Clearsilver has some built-in functions for expressions. These
functions allow access and manipulation of expression arguments.
Currently, all functions return string or numeric values. Functions
can be used in expressions anywhere a variable could be used.
| Function | Arguments | Description |
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| subcount(var) | An HDF variable |
Returns the number of child nodes for the HDF variable |
| name(local) | A local variable |
Returns the HDF variable name for a local variable alias |
| first(local) | A local variable |
Returns true iff the local variable is the first in a loop or
each |
| last(local) | A local variable |
Returns true iff the local variable is the last in a loop or
each |
| abs(expr) | A numeric expression |
Returns the absolute value of the numeric expressions |
| max(expr, expr) | Two numeric expressions |
Returns the larger of two numeric expressions |
| min(expr, expr) | Two numeric expressions |
Returns the smaller of two numeric expressions |
| string.slice(expr, start, end) | A string expression, and two numeric expressions |
Returns the string slice starting at start and ending at end,
similar to the Python slice operator |
| string.find(string, substr) | Two string expressions |
Returns the numeric position of the substring in the string (if
found), otherwise returns -1
similar to the Python string.find method |
| string.length(expr) | A string expression |
Returns the length of the string expression |
| _(expr) | A string expression |
Only available if compiled with gettext support, returns the translated
version of the string expression as returned by gettext() |
Template Filters
The Clearsilver API allows the user to add string manipulation functions
to the built-in functions. These functions can take just one string
argument and return a string. The Clearsilver CGI Kit has several Web
specific filters that are added to Clearsilver. These filters are added
by default to the CS layer of most of the language wrappers. They
are a powerful mechanism when composing URLs, providing data to
Javascript, or simply ensuring that data is HTML safe.
| url_escape |
This URL encodes the string. This converts characters such as
?, &, and = into their URL safe
equivilants using the %hh syntax. |
| html_escape |
This HTML escapes the string. This converts characters such
as >, <, and & into their
HTML safe equivilants such as >, <,
and &.
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| js_escape |
This Javascript escapes the string so it will be valid data for
placement into a Javascript string. This converts characters
such as ", ', and \ into their Javascript
string safe equivilants \", \', and \\. |
| text_html |
This pretty-formats normal text into an HTML fragment, attempting
to detect paragraph boundaries and allowing it to wrap reasonably.
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| html_strip |
This removes all HTML tags and then converts any & based HTML
escaped data into normal text. Combine this with html_escape() if you
would like to strip the HTML tags from text and display the result
in an HTML safe way. |
These filters can be used anywhere in an expression. This makes them
extremely useful for composing URLs or forcing data to be HTML
safe. Here are some examples:
<?cs var:html_escape(Page.Title) ?>
<?cs set:url = "http://www.google.com/q=" + url_escape(Query.q) ?>
<IMG onclick="handleClick('<?cs var:js_escape(url)')" SRC="foo.gif">
<A HREF="/newurl?_done=<?cs var:url_escape(url) ?>">click here</A>
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