Why doesn't the PUG mixin accept variables?

Question

HTML

Mixin:

mixin img(name, ext, alt)
  img(srcset='img/#{name}.#{ext},img/#{name}@2x.#{ext} 1.5x,img/#{name}@2x.#{ext} 2x', src='img/#{name}.#{ext}', alt='!={alt}')

Insert
+img('sail','jpg', 'alt text')
Outlet

<img srcset="img/#{name}.#{ext},img/#{name}@2x.#{ext} 1.5x,img/#{name}@2x.#{ext} 2x" src="img/#{name}.#{ext}" alt="#{alt}">

That is, the parameters are not filled with values, but remain in their original form. I also tried peeing like !{}, but it didn't help.

Answer 1

mixin img(name, ext, alt)
  img(srcset=`img/${name}.${ext},img/${name}@2x.${ext} 1.5x,img/${name}@2x.${ext} 2x', src='img/${name}.${ext}`, alt=`${alt}`)

+img('sail','jpg', 'alt text')