Human-Debugger.net - StringTemplate Introduction

Wednesday, July 08, 2009

For more background about when we use this API you can read my last post about Rendering Objects to Html

Simple Rendering of query:

   1: var query = new StringTemplate("SELECT $column$ FROM $table$;");

   2: query.SetAttribute("column", "name");

   3: query.SetAttribute("table", "User");

   4: var data = query.ToString();

We will refactor this sample to handle the queries from an outside source:

   1: var group = new StringTemplateGroup("SimpleTemplates",@"C:\Templates\TemplateEngineTestCase");

   2: var query = group.GetInstanceOf("1_simple");

   3: query.SetAttribute("column", "name");

   4: query.SetAttribute("table", "User");

   5: var data = query.ToString();

Rows 1,2 - loading the template data from a source file.

Here is the Template (1_simple.st):

//1_simple.st
SELECT $column$ FROM $table$;

Template Anonymous Type:

In the last template usage (1_simple.st) We bind the parameters using strings only. but we also have a better options: let's assume we wrote down such template:

//2_simpleObjects.st
Full Name: $Person.FirstName$ - $Person.LastName$

But let's assume that we don't have the Person class\instance, we can simply write it using the anonymous types:

   1: var user = new {FirstName = "Shani", LastName = "Raba"};

   2: var group = new StringTemplateGroup("OOTempaltes", @"C:\Templates\TemplateEngineTestCase");

   3: var query = group.GetInstanceOf("2_simpleObjects");

4:

   5: query.SetAttribute("Person", user);

You can also use this kind of bindings for setting template-attributes from each one of the Person sub-classes.

Template list:

Till now it is all pretty simple to implement by yourself, but the real issue here is the List binding feature.
You can write such template:

//3_simpleLoop.st
$items: {num1|
    <li>$num1$</li>
    }$
$end$

and bind the list using this code:

   1: var templateFolder = new StringTemplateGroup("SimpleLoopTemplates", @"C:\Tempaltes\TemplateEngineTestCase");

   2: var template = templateFolder.GetInstanceOf("3_simpleLoop");

3:

   4: template.SetAttribute("items", new List<string> {"Shani", "Doron", "Nati", "Yossi"});

Conclusion:

The code is pretty simple, the templates engine implements good functionality and is well documented.
The StringTemplate syntax is easy to learn and well documented.
I still don't like it when I need to learn a new language\syntax - it will sharpen the newbie's curve.
StringTemplate is missing good Object2Template Designer.

Wednesday, July 08, 2009 8:13:57 AM (GMT Daylight Time, UTC+01:00)

Comments [1] - Trackback
.Net 3.5 | Scripting Technology

Sunday, July 26, 2009 10:51:33 PM (GMT Daylight Time, UTC+01:00)

c# suck big time in that area.

Ruby (and even Boo) have string interpolation boiled into the default environment, in a far easier syntax.

see ERB (ruby)

and Boo

And javascript has EJS

Ken Egozi

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