The regular expression matching __.net of vim custom functions

The original intention is to implement a Vim plug-in, be able to automate the implementation of the method declared in H-header files in C + + into the CPP implementation file (the C.vim I know is not implemented as I meant, implemented well in the source menu in Eclipse), using the line that needs to parse the current cursor, such as:

Need to be

void SayHello (int msg,string buffer);

Converted to

void Hello::sayhello (int msg,string msg2) {

}

Must parse out the return value function name, the parameter and so on, uses the VIM built-in function to be possible to solve, because the regular expression and the general wording is slightly different, has made the memo, for instance

() need to add days add \ \ (\)

[] No

{} needs to be written as \{\}

? need to write \?

Matchlist (' Hello World (int msg,string msg2) ', ' (. *\) \s\+\ (. *\) \s* (\ (. *\))

This function returns a list

[' Hello World (int msg,string msg2); ', ' Hello ', ' world ', ' int msg,string msg2 ', ', ', ', ', ', ', ', ', ', ', ', '

You can resolve the return list to continue.

The complete plugin is as follows (need to install switch header file and implement file plugin A.vim)

if exists("loaded_generate_impl_corey")
        finish  
endif
let loaded_generate_impl_corey=1
 
function <SID>GetClassName(lineNum)
        let tmplinenum=a:lineNum
        while tmplinenum>0
                let tmplinenum-=1
                let tmpline=getline(tmplinenum)
                let clslist=matchlist(tmpline,'\s*class\s*\(\S*\)\s*.*')
                if stridx(tmpline,'class ')>=0
                        return get(clslist,1)
                endif   
        endwhile
        return ""
endfunction


function <SID>ToImpl()
        let s:curline=getline(line("."))
        let s:flist= matchlist(s:curline, '\s*\(.*\)\s\+\(.*\)\s*(\(.*\));')
        if strlen(get(s:flist,0))== 0 || strlen(get(s:flist,2))== 0
                echo "this is not a function"
                return  
        endif   
        let s:rtn=get(s:flist,1)
        if s:rtn=='virtual'
                let s:rtn=""
        endif   
        let s:method=get(s:flist,2)
        let s:args=get(s:flist,3)
        let s:classname=<SID>GetClassName(line("."))
        let s:implclause="\n\t".s:rtn . (strlen(s:rtn)==0?"":" ") .s:classname."::". s:method . "(". s:args . ")" . "{" . "\n" ."\n"."\t"."}"
        call setreg('',s:implclause)
        execute ":A" 
        execute "normal G"
        execute "normal p"
        call cursor(line(".")+2,0)
endfunction     

nnoremap zz :call <SID>ToImpl()<CR>