15. Golo template engine

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Golo comes with a built-in template engine that is reminiscent of Java Server Pages or Ruby ERB. It compiles template text into Golo functions.

15.1. Example

Consider the following example.

let template = """
<%@params posts %>
<!DOCTYPE html>
<html>
  <head>
    <title>Golo Chat</title>
  </head>
  <body>
  <form action="/" method="post">
    <input type="text" name="msg">
    <input type="submit" value="Send">
  </form>
  <div>
    <h3>Last posts</h3>
    <% foreach post in posts { %>
      <div>
        <%= post %>
      </div>
    <% } %>
  </div>
  </body>
</html>
"""

This multi-line string has a Golo template. It can be compiled into a function as follows:

let tpl = gololang.TemplateEngine(): compile(template)
println(tpl(someDataModel: posts()))

15.2. Directives

As you may have guess from the previous example:

Golo code snippets are placed in <% %> blocks, and
expressions can output values using <%= %>, and
<%@import foo.bar.Baz %> causes foo.bar.Baz to be imported, and
<%@params foo, bar, baz %> causes the template function to have 3 parameters, i.e., it is a |foo, bar, baz| { ... } function.

When no <%@params ... %> exists, the function is assumed to have a single params parameter.

Warning

The template engine is a simple one and makes no verification either on the templates or the resulting Golo source code. The compile method may throw a GoloCompilation exception though, and you can query the exception getSourceCode() and getProblems() methods to obtain more details.