Above code is not working for me,
It should be complaining along the lines of String found where operator expected at - line 1, near "print_argu "Hello function!\n"", and if you add diagnostics

String found where operator expected at - line 1, near "print_argu "He
+llo
    function!\n"" (#1)
    (S syntax) The Perl lexer knows whether to expect a term or an ope
+rator.
    If it sees what it knows to be a term when it was expecting to see
+ an
    operator, it gives you this warning.  Usually it indicates that an
    operator or delimiter was omitted, such as a semicolon.
    
    (Do you need to predeclare print_argu?)
syntax error at - line 1, near "print_argu "Hello function!\n""
Execution of - aborted due to compilation errors (#2)
    (F) Probably means you had a syntax error.  Common reasons include
+:
    
        A keyword is misspelled.
        A semicolon is missing.
        A comma is missing.
        An opening or closing parenthesis is missing.
        An opening or closing brace is missing.
        A closing quote is missing.
    
    Often there will be another error message associated with the synt
+ax
    error giving more information.  (Sometimes it helps to turn on -w.
+)
    The error message itself often tells you where it was in the line 
+when
    it decided to give up.  Sometimes the actual error is several toke
+ns
    before this, because Perl is good at understanding random input.
    Occasionally the line number may be misleading, and once in a blue
+ moon
    the only way to figure out what's triggering the error is to call
    perl -c repeatedly, chopping away half the program each time to se
+e
    if the error went away.  Sort of the cybernetic version of S<20
    questions>.
    
Uncaught exception from user code:
    syntax error at - line 1, near "print_argu "Hello function!\n""
Execution of - aborted due to compilation errors.
 at - line 4
[download]