How to get StringTemplate V4 to ignore < as delimiter?

Question

I'm using StringTemplate V4 to generate some HTML code in my project. I need to have HTML formatting in my templates, so using the default delimiters < and > would be very awkward.

So, I'm creating a group passing the delimiter as argument (as recommended by this question), but it simply doesn't work.

Here is my test code:

public void testTemplate() {
    char sep = '$';
    STGroup stGroup = new STGroupString("temp",
            "<html>hello, $name$!</html>", sep, sep);
    System.out.println("Group created");
    ST st = stGroup.getInstanceOf("temp");
    if (st == null) {
        System.out.println("Failed to get template!");
    } else {
        st.add("name", "Guest");
        System.out.println("Template initialized correctly");
    }
}

And this is the output that I get:

temp 1:1: invalid character '<'
temp 1:5: invalid character '>'
temp 1:1: garbled template definition starting at 'html'
temp 1:6: garbled template definition starting at 'hello'
temp 1:13: invalid character '$'
temp 1:18: invalid character '$'
temp 1:19: invalid character '!'
temp 1:21: invalid character '<'
temp 1:22: invalid character '/'
temp 1:14: garbled template definition starting at 'name'
temp 1:26: invalid character '>'
temp 1:22: garbled template definition starting at 'html'
Failed to get template!

What am I missing here?

It works with just the template, but I really need to use the group because in the real code I need to register renderers. — Elias Dorneles, Jun 21 '12 at 20:30

score 5 · Accepted Answer · 2016-01-26T20:44:33.590

The issue is the the template supplied to the STGroupString constructor is not valid "group template" syntax.

To get a Group Template that doesn't require the special syntax try:

STGroup group = new STGroup('$', '$');
group.registerRenderer(...);
CompiledST compiledTemplate = group.defineTemplate("name", ...);
compiledTemplate.hasFormalArgs = false; // very important!

// later on...
ST template = group.getInstanceOf("name");

(This above is an adaptation of my C# code so YMMV. I have tried to ensure the types/names are valid and the syntax is correct, but have not verified it. Feel free to update/correct as required.)

Happy coding.

This works, it's just a bit odd that the method ` defineTemplate(String, String)` has the Javadoc comment `for testing`. So this is probably not how it was intented. — wvdz, May 27 '14 at 13:47

score 1 · Answer 2 · answered Sep 04 '12 at 12:53

Very interesting trick above (by pst), which also gives a hint: "not valid group template syntax".

So, for reference, here is an alternative to his code, using a valid syntax for such group:

 STGroup groupS = new STGroupString("some group", "val(value) ::= \"<span>Value is {value; format=\\\"%1.5f\\\"}</span>\"", '{', '}');
 groupS.registerRenderer(Number.class, new NumberRenderer());
 ST valTpl = groupS.getInstanceOf("val");
 valTpl.add("value", 3.14159265358979353);
 System.out.println(valTpl.render());

The syntax becomes unwieldy within Java strings, with the many escapes...

How to get StringTemplate V4 to ignore < as delimiter?

2 Answers2

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