I'm trying to insert a filename into text as below::put=expand(%)but I've the following errors:E116: Invalid arguments for function expand(  E15: Invalid expression: expand(Why this doesn't work?What's most surprising thing is that it works when using single-quote instead, e.g.::put=expand('%')So I'm trying to understand:Is there any differences between using double-quotes or single-quotes? If so, what kind?I'm using Vim v7.4.
Why I'm getting Invalid arguments for the function when using double-quotes?
command line;error
From :help :put:The register can also be = followed by an optional expression. The expression continues until the end of the command. You need to escape the | and  characters to prevent them from terminating the command.For the difference between  and ' in the context of an expression, see :help expr-quote and :help expr-'.