bert 1.1.1

bert - better engine for runtime templates

bert is an HTML-oriented run-time (instead of compile-time) templating engine implemented in D. Templates contain next to no logic (with surprisingly adept capabilities for checking existing variables).

Why run-time?

bert was built to support applications that require customizable templates, without recompiling the entire application. bert templates still parse and render very quickly and can be cached very easily.

Features

• (( $variable )) -- variables are always prefixed with $, like in shell script or perl
• (? condition ?), (% else %) and (% end %) for conditional blocks, for example, to check if variable "v" is set:

  (? $v ?)
     v is set
  (% else %)
     v is not set
  (% end %)

• the else clause on conditionals can obviously be omitted
• (@ $needle; $haystack @) to iterate over an array, for example, to iterate over the 'users' array:

  (@ $user; $users @)
     (( $user.name ))
  (% end %)

• Iterator blocks will set $FIRST or $LAST on the first and last items respectively, but won't anywhere else (useful for comma-separating a list)
• ! before variable/expression to invert the truthiness of a value, !! just to convert it to a boolean
• (= $variable =) for a raw variable that doesn't escape (X|HT)ML characters
• (^ $variable (or "string") ^) to include a template initialized by a loader
• you can index into an array by accessing it like a member (as a workaround for not being able to access members.) for example, (( $array.0 )) functions as array[0] would in D. this also works for associative arrays (e.g. (( $array.key )) evaluating to array["key"])
• anything outside double-parenthesis will be ignored and included as raw text in the template's output

Usage

Example

source/app.d:

module app;

import std.stdio : writefln;
import std.file : readText;

import bert.context;
import bert.structure;
import bert.loader;

void main() {
    // The Context holds variables for the template to reference.
    Context ctx = Context();
    ctx.set("sixty", "ten");
    ctx.set("user", [
        "name": "midna",
        "email": "[email protected]"
    ]);
    ctx.set("fruits", ["grape","orange","apple"]);

    // Loaders load templates in a fashion that allows them to include others. It also provides
    // a prettier API :)
    Loader loader = new Loader("./templates");
    writefln("%s", loader.render("test", ctx));
}

templates/test.bert:

(( $sixty ))     (# => "ten" #)
(( $fruits.1 ))  (# => "orange" #)
(( $user.name )) (# => "midna" #)

(# a comma-separated, weirdly-spaced list of all elements in 'fruits' #)
(@ $fruit; $fruits @)(( $fruit ))(? !$LAST ?), (% end %)(% end %)

Reuse

bert is made available under the terms of the Lesser GNU General Public License, version 2.0