You can also use diagnostics; to help debug errors (emphasis is mine). 
    (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.

[download]
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>.

[download]

In reply to Re: factorial through recursion (diagnostics) by toolic
in thread factorial through recursion by hnd

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