cl-closure-template - Common Lisp implementation of Closure Template from Google

Sample Code

 CL-USER> (asdf:operate 'asdf:load-op '#:closure-template)

 CL-USER> (defparameter *template* "
 /*
  *  Greets a person using 'Hello' by default.
  */
{namespace closureTemplate.Example}
{template helloName}
   {if not $greetingWorld}
      Hello {$name}!
   {else}
      {$greetingWorld} {$name}!
    {/if}
{/template}")
*TEMPLATE*


CL-USER> (closure-template:compile-template :common-lisp-backend *template*)
#<PACKAGE "CLOSURETEMPLATE.EXAMPLE">
CL-USER> (closuretemplate.example:hello-name '(:name "Andrey"))
"Hello Andrey!"
CL-USER> (closure-template.example:hello-name '(:name "Andrey" :greeting-world "Hi"))
"Hi Andrey!"


CL-USER> (closure-template:compile-template :javascript-backend *template*)
"if (typeof closureTemplate === 'undefined') { closureTemplate = {}; }
if (typeof closureTemplate.Example === 'undefined') { closureTemplate.Example = {}; }

closureTemplate.Example.$isEmpty$ = function (obj) {
    for (var prop in obj) if (obj.hasOwnProperty(prop)) return false;
    return true;
};

closureTemplate.Example.$escapeHTML$ = function (obj) {
    if (typeof obj == 'string') return String(obj).split('&').join('&amp;').split( '<').join('&lt;').split('>').join('&gt;').split('\\\"').join('&quot;').split('\\'').join('&#039;');
    else return obj;
};

closureTemplate.Example.$round$ = function (number, ndigits) {
    if (ndigits) {
        var factor = Math.pow(10.0, ndigits);
        return Math.round(number * factor) / factor;
    }
    else return Math.round(number)
};

closureTemplate.Example.$objectFromPrototype$ = function (obj) {
    function C () {}
    C.prototype = obj;
    return new C;
};

closureTemplate.Example.helloName = function($env$, $target$) {
    if (!$env$) { $env$ = {}; }
    var $result$ = $target$ || [];

    if (!$env$.greetingWorld) {
        $result$.push(\"Hello \");
        $result$.push(closureTemplate.Example.$escapeHTML$($env$.name));
        $result$.push(\"!\");
    }
    else {
        $result$.push(closureTemplate.Example.$escapeHTML$($env$.greetingWorld));
        $result$.push(\" \");
        $result$.push(closureTemplate.Example.$escapeHTML$($env$.name));
        $result$.push(\"!\");
    }

    if (!$target$) return $result$.join('');
    else return null;
};
"

CL-USER> (closure-template:compile-template :requirejs-backend *template*)
"define(function () {
var module = { };
module.$isEmpty$ = function (obj) {
    for (var prop in obj) if (obj.hasOwnProperty(prop)) return false;
    return true;
};

module.$escapeHTML$ = function (obj) {
    if (typeof obj == 'string') return String(obj).split('&').join('&amp;').split( '<').join('&lt;').split('>').join('&gt;').split('\\\"').join('&quot;').split('\\'').join('&#039;');
    else return obj;
};

module.$round$ = function (number, ndigits) {
    if (ndigits) {
        var factor = Math.pow(10.0, ndigits);
        return Math.round(number * factor) / factor;
    }
    else return Math.round(number)
};

module.$objectFromPrototype$ = function (obj) {
    function C () {}
    C.prototype = obj;
    return new C;
};

module.helloName = function($env$, $target$) {
    if (!$env$) { $env$ = {}; }
    var $result$ = $target$ || [];

    if (!$env$.greetingWorld) {
        $result$.push(\"Hello \");
        $result$.push(module.$escapeHTML$($env$.name));
        $result$.push(\"!\");
    }
    else {
        $result$.push(module.$escapeHTML$($env$.greetingWorld));
        $result$.push(\" \");
        $result$.push(module.$escapeHTML$($env$.name));
        $result$.push(\"!\");
    }

    if (!$target$) return $result$.join('');
    else return null;
};
return module; });"

Adding Custom Print Directives

You can add custom print directives. For example, printing integers as hexadecimal values:

CL-USER> (closure-template:define-print-syntax printHex "hex" (:constant t)) 
CLOSURE-TEMPLATE.PARSER::PRINT-DIRECTIVE
CL-USER> (closure-template:register-print-handler :common-lisp-backend 'printHex :function #'(lambda (params end value) (format nil "~X" value)))
#<Anonymous Function #x302001B7085F>
CL-USER> (defparameter *template* "
     /*
      *  Greets a person using 'Hello' by default.
      */
    {namespace closureTemplate.Example}
    {template helloName}
    Hello {$name} {$param|hex}!
    {/template}")
*TEMPLATE*
CL-USER> (closure-template:compile-template :common-lisp-backend *template*)
#<Package "CLOSURE-TEMPLATE.EXAMPLE">
CL-USER> (closure-template.example:hello-Name '(:name "Name" :param 128))
"Hello Name 80!"

To use Javascript backend, you need to register a handler for Javascript or RequireJS backends. This is a more complex example which shows how to handle parameters of the directive:

CL-USER> (closure-template:define-print-syntax printHex (and "hex" (esrap:? (and ":" (or "upper" "lower"))))
           (:destructure (tag value)
                         (declare (ignore tag))
                         (list (if (and value (string= (second value) "lower")) 'case-lower 'case-upper))))
PRINT-HEX
CL-USER> (closure-template:register-print-handler :common-lisp-backend 'printHex
                                                  :function #'(lambda (params env value)
                                                                (declare (ignore env))
                                                                (format nil (if (member 'case-lower params) "~(~X~)" "~X") value)))
PRINT-HEX
CL-USER> (closure-template:register-print-handler :javascript-backend 'printHex
                                         :handler "function (params, value) { var result = value.toString(16); if (params.case == \"upper\") { result = result.toUpperCase(); } return result; }"
                                         :parameter-converter #'(lambda (params)
                                                                  (format nil "{ case: \"~A\"; }" (if (member 'case-lower params) "lower" "upper"))))

PRINTHEX
CL-USER> (defparameter *template* "
     /*
      *  Greets a person using 'Hello' by default.
      */
    {namespace closureTemplate.Example}
    {template helloName}
    Hello {$name} {$param|hex:lower}!
    {/template}")
*TEMPLATE*
CL-USER> (closure-template.example:hello-name '(name "Name" :param 143))
"Hello Name 8F!"

You can also use a predefined function by name or RequireJS module. For detals, please see docstrings for REGISTER-PRINT-HANDLER implementations.