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## Variable |
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The simplest templates command is showing variable. The syntax is trivial: |
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VARIABLE |
'=' VARIABLE |
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For example, if you want to show a content value `message` just write: |
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<% message %> |
<%= message %> |
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It is actually translated to C++ code: |
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out()<<cppcms::filters::escape(content.message); |
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Where `escape` function writes the `message` member variable |
of the content to the stream and escapes special HTML |
characters `<`, `>`, `&`, `"` with their HTML representations like `<` |
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If you want to get a value of some property, you just write. |
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<% some_property() %> |
<%= some_property() %> |
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Which is translated to: |
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out()<<cppcms::filters::escape(content.some_property()); |
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## Variable with filters |
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You can add arbitrary filters to the variable you show. The syntax is following: |
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VARIABLE [ '|' filter [ '|' filter ] ... ] |
'=' VARIABLE [ '|' filter [ '|' filter ] ... ] |
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Where `filter` is |
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[ 'ext' ] NAME [ '(' ( VARIABLE | STRING | NUMBER ) [ ',' ( VARIABLE | STRING | NUMBER ) ] ... ] |
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### Description |
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If no filters, are given the variable is automatically escaped, but if you provide any filter they are used instead |
of escaping. |
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Each variable is actually a creation or call |
of special filter object with given parameters, |
where first parameter is the "filtered" variable and |
others are filter parameters. For example: |
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<% birthday | strftime("%d/%m/%Y") %> |
<%= birthday | strftime("%d/%m/%Y") %> |
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Is translated into: |
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out()<<cppcms::filters::strftime(content.birthday,"%d/%m/%Y"); |
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You can also concatenate filters using pipe symbol: |
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<% birthday | strftime("%d %m %Y") | urlencode %> |
<%= birthday | strftime("%d %m %Y") | urlencode %> |
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Would be rendered as: |
out()<<cppcms::filters::urlencode(cppcms::filters::strftime(content.birthday,"%d/%m/%Y")); |
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There is a set of filters predefined available for you, see [cppcms::filters](/cppcms_ref_v0_99_1/namespacecppcms_1_1filters.html) namespace reference. |
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One of the filters that are worth to notice is `raw` filter |
that allows write an output variable as-is without |
HTML escaping. |
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<% ready_html | raw %> |
<%= ready_html | raw %> |
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The `ready_html` variable would be written as-is to output |
stream without escaping HTML symbols like `<`. |
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You can specify arbitrary external filters that are defined in `content` class. For example: |
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namespace data { |
struct page { |
... |
virtual string bbcode(string const &); |
... |
}; |
} |
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Then in template we can specify: |
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<% class page uses data::page %> |
<% template render() %> |
<% message | ext bbcode %> |
<%= message | ext bbcode %> |
<% end %> |
<% end %> |
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__Note:__ Under Windows platform, dynamically loaded libraries (dll) do not allow undefined symbols. |
Thus, if you want to support Windows, you should create your filters as virtual functions or |
callbacks like `booster::function<>` in order to prevent referring to external symbol. |
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## Variable - Deprecated Syntax |
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CppCMS supports older deprecated syntax (without "="): |
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VARIABLE [ '|' filter [ '|' filter ] ... ] |
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However it is not recommended due to fact that new |
template keywords may be introduced that would hide the existing variable and cause syntax error. |
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## Internationalization |
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### Syntax |
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'gt' STRING [ 'using' using-options ] |
'ngt' STRING ',' STRING ',' VARIABLE [ 'using' using-options |
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Where `using-options` is: |
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display-variable-block [ ',' display-variable-block [ ',' ... ] ] |
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Where `display-variable-block` is any variable of optional filters as described above. For example: |
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<% gt "Press the button" %> |
<% gt "Hello Dear {1}, we are glad to see you!" using name %> |
<% gt "Hello <a href=\"{1}\">{2}</a> you have {3}" using link | urlencode , name , something %> |
<% ngt "You have one apple","You have {2} apples",n using n %> |
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### Description |
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`gt` -- `gettext` translates given string according to locale defined in the output stream. For example: |
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<% gt "Press the button" %> |
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Would be translated as "Press the button" in English locale and "Нажмите кнопку" under Russian locale. |
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You can specify additional parameters using `using` option. You provide a list of comma separated values |
as you would display a variable. You can use any other filters as usual. "{1}", "{2}" etc, specify the order of |
input variables. It uses [`booster::locale::format`](/cppcms_ref_v0_99_1/classbooster_1_1locale_1_1basic__format.html) or [`cppcms::locale::format`](/cppcms_ref_v0_99_1/classcppcms_1_1locale_1_1basic__format.html) for such substitutions (according to localization backend |
CppCMS compiled with.) |
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`ngt` -- `ngettext` translate plural form for given integer. Where first parameter is single form, second plural and the |
third should be the variable is used. |
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_Notes:_ |
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1. When you use `ngt` you encouraged to use `using` syntax, because you should provide an actual number to display. |
3. You may use `<% if rtl %>` or `<% if not rtl %>` in order to test direction of text. This is actually equivalent to: |
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<% if (cppcms::locale::gettext("LTR",out().getloc())=="RTL") %> |
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See `if` statement for further description. |
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## Including other templates |
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### Syntax |
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'include' IDENTIFIER '(' [ parameter [ ',' parameter ...] ] ')' |
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Where `parameter` is one of VARIABLE, STRING or NUMBER. For example: |
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<% include title() %> |
<% include parent::foo() %> |
<% include bar(x,"test",-1.0) %> |
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### Description |
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This command allows inclusion of other templates in place (actually calling other member functions.) You can include existing implementation in parent views |
in order to extend them. For example: |
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<% view master uses data::master %> |
<% template menu() %> |
<li><a href="#1">Main</a></li> |
<li><a href="#2">Products</a></li> |
<% end template %> |
<% template render() %> |
<ul><% include menu() %></ul> |
<% end template %> |
<% end view %> |
<% view sales uses data::sales extends master %> |
<% template menu() %> |
<% include master::menu() %> |
<li><a href="#3">Orders</a></li> |
<% end %> |
<% end %> |
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The above code extends menu for view `sales` with an additional option. |
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## Rendering Forms |
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### Syntax |
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'form' ('as_p' | 'as_table' | 'as_ul' | 'as_dl' | 'as_space' | 'input' | 'begin' | 'end' ) VARIABLE |
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`as_*` flags allow you to render `cppcms::form`, with |
specific delimiters, when `input`, `begin` and `end` flags |
allow you to render single part of the widget. |
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### Description |
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Forms are organized as form object or sets of widgets. Each set can be rendered using different delimiters: |
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- `as_p` -- use HTML paragraphs. |
- `as_table` -- use table. _Note_: `<table>...</table>` tags are not added user should specify them. |
- `as_ul` -- as list (using `<li>..</li>`). `<ul>..</ul>` are not specified. |
- `as_dl` -- as definition list. `<dl>` tags are not specified, `<dt>..</dt>` and `<dd>..</dd>` are used. |
- `as_space` -- put blanks between elements. |
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For example: |
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<table> |
<% form as_table form.fields %> |
</table> |
<p><% form as_space form.submit_buttons %></p> |
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May be rendered as: |
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<table> |
<tr><th>User Name:</th><td><input ... /></td></tr> |
<tr><th>Password: </th><td><input ... /></td></tr> |
</table> |
<p><input ... value="Login" /> <input ... value="Forgot Password" /></p> |
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Sometimes you want to perform custom rendering |
of widgets that is not predefined by this list. |
In such case you may render only `<input ...>` field |
of the widget by calling |
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<% form input some_button %> |
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Which would be rendered like this: |
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<input type="submit" name="_3" value="Press" /> |
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Note, `input` does not strictly means that it is limited |
for widgets using HTML `input` tag, it works for |
any other widget just limited to actual content rendering |
without "help" messages, for example, for widget |
`cppcms::widgets::textarea` it would be `<textarea ...>some text</textarea>` |
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Sometimes you need even more fine grained access |
to widget rendering parts, for example you may |
want to add some attributes to the widget in the view. |
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You may render `begin` or `end` part of the widget, such that you can insert HTML attributes between them or even JavaScript. |
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<% form begin some_button %> onclick="return foo()" <% form end some_button %> |
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Which would be rendered as |
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<input type="submit" name="_3" onclick="return foo()" value="Press" /> |
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For generation of custom HTML for widgets you can |
always use widget properties directly: |
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<input type="submit" name="<% button.name() %>" value="Press" /> ( <% button.help() %> ) |
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See: [`cppcms::widgets` namespace](/cppcms_ref_v0_99_1/namespacecppcms_1_1widgets.html) for documentation of |
each specific widget properties. |
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## Selecting HTML/XHTML |
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You may request generation HTML or XHTML code in forms using following command: |
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( 'xhtml' | 'html' ) |
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Note, this command has global effect on all template without connection to specific class. You should include it |
in the topmost class of your view. |
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<% c++ #include "all_data.h" %> |
<% xhtml %> |
<% skin %> |
<% view master uses data::master %> |
<% template render() %> |
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" |
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> |
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Currently, this option affects only forms code generation. |
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## Injecting C++ Code |
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You can always inject any kind of C++ code using: |
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"c++" any-c++-statement |
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For example: |
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<% c++ #include "all_content.h" %> |
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__Notes:__ |
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1. If you want to refer to content variables in your code, do not forget to use `content` member of your class. For example: |
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<% a %> + <% b %> = <% c++ out()<<content.a+content.b; %> |
2. Generally you should not use C++ code in template, use it if it is absolutely necessary. |
3. If you want use special conditions prefer specialized if statement over `<% c++ if() { %>...<% c++ } %>` |
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