How to use comments in Handlebar templates?
The newest version of Handlebars has block comments support : {{!– {{commented expressions}} –}} https://github.com/wycats/handlebars.js/commit/a927a9b0adc39660f0794b9b210c9db2f7ddecd9
templates
How to load jinja template directly from filesystem
Here’s how: use a FileSystemLoader instead of a PackageLoader. I found examples on the web here and here. Let’s say you have a python file in the same dir as your template: ./index.py ./template.html This index.py will find the template and render it: #!/usr/bin/python import jinja2 templateLoader = jinja2.FileSystemLoader(searchpath=”./”) templateEnv = jinja2.Environment(loader=templateLoader) TEMPLATE_FILE = “template.html” … Read more
Template function inside template class
Write this: template <class T> template <class U> void MyClass<T>::foo() { /* … */ }
How to access class constants in Twig?
Just to save your time. If you need to access class constants under namespace, use {{ constant(‘Acme\\DemoBundle\\Entity\\Demo::MY_CONSTANT’) }}
Why use “b < a ? a : b” instead of “a < b ? b : a” to implement max template?
std::max(a, b) is indeed specified to return a when the two are equivalent. That’s considered a mistake by Stepanov and others because it breaks the useful property that given a and b, you can always sort them with {min(a, b), max(a, b)}; for that, you’d want max(a, b) to return b when the arguments are … Read more
C++ SFINAE examples?
I like using SFINAE to check boolean conditions. template<int I> void div(char(*)[I % 2 == 0] = 0) { /* this is taken when I is even */ } template<int I> void div(char(*)[I % 2 == 1] = 0) { /* this is taken when I is odd */ } It can be quite useful. … Read more
When to use std::forward to forward arguments?
Use it like your first example: template <typename T> void f(T && x) { g(std::forward<T>(x)); } template <typename …Args> void f(Args && …args) { g(std::forward<Args>(args)…); } That’s because of the reference collapsing rules: If T = U&, then T&& = U&, but if T = U&&, then T&& = U&&, so you always end up … Read more
Check if a class has a member function of a given signature
Here’s a possible implementation relying on C++11 features. It correctly detects the function even if it’s inherited (unlike the solution in the accepted answer, as Mike Kinghan observes in his answer). The function this snippet tests for is called serialize: #include <type_traits> // Primary template with a static assertion // for a meaningful error message … Read more
Officially, what is typename for?
Following is the quote from Josuttis book: The keyword typename was introduced to specify that the identifier that follows is a type. Consider the following example: template <class T> Class MyClass { typename T::SubType * ptr; … }; Here, typename is used to clarify that SubType is a type of class T. Thus, ptr is … Read more
Bash Templating: How to build configuration files from templates with Bash?
Try envsubst $ cat envsubst-template.txt Variable FOO is (${FOO}). Variable BAR is (${BAR}). $ FOO=myfoo $ BAR=mybar $ export FOO BAR $ cat envsubst-template.txt | envsubst Variable FOO is (myfoo). Variable BAR is (mybar).