@let foo = bar+baz;
_let foo = bar+baz;
@let foo = bar+baz; _let foo = bar+baz;
   @let   foo   =    bar+baz;   
   _let   foo   =    bar+baz;   
text @let foo = bar+baz; text
text @let foo = bar+baz; text
   text  @let   foo   =    bar+baz;  text 
@if(foo){bar}
@let foo = bar+baz;