Twig template engine in c++

Supported tags:

apply, autoescape, block, embed, extends, for, from, if, import, include, macro, set, verbatim, with, filter

Supported functions:

cycle, date, include, max, min, parent, random, range, block, parent

Supported filters:

join, lower, upper, default, e, escape, defined, length, first, last, raw, safe, batch, merge, date, abs, capitalize, filter, trim, keys, format, json_encode, find, map, reduce, round, slice

Supported tests:

defined, divisible by, empty, even, iterable, mapping, null, odd, sequence

All data is represented by the Variant type that is a polymorphic JSON type object that can store primitive types, arrays, dictionaries and functions.

Create a loader:

std::shared_ptr loader(new DictTemplateLoader({ {"base1.html.twig", R"({% block head %}<title>{% block title %}{% endblock %}</title>{% endblock %}{% block content %}{% endblock %}

{% block footer %}footer{% endblock %})"}, })) ;

Create a renderer:

TemplateRenderer rdr(loader) ;

Define the context data:

Variant::Object ctx{ {"users", Variant::Array{ Variant::Object{{"name", "Alice"}}, Variant::Object{{"name", "Bob"}}, Variant::Object{{"name", "Charlie"}} }} } ;

Render a template

string res = rdr.render('base1.html.twig', ctx);

You may declare custom functions, filters, test by means of the global FunctionFactory object.

FunctionFactory::instance().registerFunction("lipsum",
[](const Variant &args) -> Variant {
    Variant::Array vargs ;
    unpack_args(args, {"data"}, vargs) ;

  if ( !vargs.empty() ) {
      auto n = vargs[0].toInteger() ;
       string res ;
       for ( int64_t i = 0 ; i < n ; ++i ) res += "Lorem ipsum dolor sit amet, consectetur > adipiscing elit. " ;
       return res ;
   }
   else return string() ;

});

Function arguments are packed into a Variant::Object. args["args"] holds and array of positional variables, and args["kw"] a dictionary of named arguments. Use unpack_args to convert to an array of posibly undefined values.