Error characters in vimrc function

Question

I'm trying to run a function that is in my vimrc to insert dependencies in a php class.
The script must enter a parameter type hinting in the construct of my class and assign the result of this parameter to an attribute of the local class.
I'm using Linux and I found in some posts that these types of characters that are in the function are not used to Linux. But for Mac.

The function:

function! AddDependency()
    let dependency = input('Var Name: ')
    let namespace = input('Class Path: ')

    let segments = split(namespace, '\')
    let typehint = segments[-1]

    exec 'normal gg/construct^M:H^Mf)i, ' . typehint . ' $' . dependency . '^[/}^>O$this->^[a' . dependency . ' = $' . dependency . ';^[?{^MkOprotected $' . dependency . ';^M^[?{^MOuse ' . namespace . ';^M^['

    " Remove opening comma if there is only one dependency
    exec 'normal :%s/(, /(/g'

endfunction

And when I try to run this function I get:

Error detected while processing function AddDependency:
line   10:
E115: Missing quote: 'normal :%s/(, /(/g
E15: Invalid expression: 'normal :%s/(, /(/g
Press ENTER or type command to continue

What is exactly this special chars?
How can I fixed this and is there some reference to learn about this chars?

Thanks advance..

Answer 1

Instead of

exec 'normal :%s/(, /(/g'

You should just do

:%s/(, /(/g

Along with fixing the ^M and ^[ issues that should solve your problem.