Re: Improving 'syntax error, unexpected $end, expecting kEND'?

Thanks for filling these in Martin.  I worry that this is such a simple 
thing that there must be some reason it wasn't done before....  Impact 
on performance?  Breaking the Ripper code?

It occurs to me that maybe the end-of-file line should just be

   end_of_file 0

instead of

   end_of_file 0 "end-of-file"

that ought to get rid of the misleading quotes that make "end-of-file" 
appear like a keyword.  I tried using "EOF" as the token name, but there 
was already a macro with that name and that messed everything up.

	David

Martin Duerst wrote:
> At 04:15 07/10/24, David Flanagan wrote:
>> The patch below changes this message to:
>>
>> syntax error, unexpected "end-of-file", expecting "end"
>>
>> It doesn't tell you where the outermost open block begins, but at least the message isn't so cryptic.  I don't know any way to get rid of the quotes around "end-of-file".
> 
> This looks extremely helpful, in particular for (relative) beginners.
> Looking at the patch below, it seems to be easy to improve things for
> a few other cases, too. I just tried to fill in the blanks; maybe
> some of this stuff doesn't make sense, but I have included a patch
> below.
> 
> As for personal experiences, when I get an error of this kind,
> I often add an "end" at some arbitrary place and see what happens.
> Then I move that "end" around a bit and see again what happens.
> That usually leads to a solution pretty quickly. Seems that sometimes
> randomized algorithms are useful even for programming :-).
> 
> Regards,    Martin.
> 
> 
> Index: parse.y
> ===================================================================
> --- parse.y     (revision 13764)
> +++ parse.y     (working copy)
> @@ -596,54 +596,55 @@
>  /*%
>  %token <val>
>  %*/
> -       keyword_class
> -       keyword_module
> -       keyword_def
> -       keyword_undef
> -       keyword_begin
> -       keyword_rescue
> -       keyword_ensure
> -       keyword_end
> -       keyword_if
> -       keyword_unless
> -       keyword_then
> -       keyword_elsif
> -       keyword_else
> -       keyword_case
> -       keyword_when
> -       keyword_while
> -       keyword_until
> -       keyword_for
> -       keyword_break
> -       keyword_next
> -       keyword_redo
> -       keyword_retry
> -       keyword_in
> -       keyword_do
> -       keyword_do_cond
> -       keyword_do_block
> +       end_of_file 0   "end-of-file"
> +       keyword_class   "class"
> +       keyword_module  "module"
> +       keyword_def     "def"
> +       keyword_undef   "undef"
> +       keyword_begin   "begin"
> +       keyword_rescue  "rescue"
> +       keyword_ensure  "ensure"
> +       keyword_end     "end"
> +       keyword_if      "if"
> +       keyword_unless  "unless"
> +       keyword_then    "then"
> +       keyword_elsif   "elsif"
> +       keyword_else    "else"
> +       keyword_case    "case"
> +       keyword_when    "when"
> +       keyword_while   "while"
> +       keyword_until   "until"
> +       keyword_for     "for"
> +       keyword_break   "break"
> +       keyword_next    "next"
> +       keyword_redo    "redo"
> +       keyword_retry   "retry"
> +       keyword_in      "in"
> +       keyword_do      "do"
> +       keyword_do_cond "do"
> +       keyword_do_block        "do"
>         keyword_do_LAMBDA
> -       keyword_return
> -       keyword_yield
> -       keyword_super
> -       keyword_self
> -       keyword_nil
> -       keyword_true
> -       keyword_false
> -       keyword_and
> -       keyword_or
> -       keyword_not
> -       modifier_if
> -       modifier_unless
> -       modifier_while
> -       modifier_until
> -       modifier_rescue
> -       keyword_alias
> -       keyword_defined
> -       keyword_BEGIN
> -       keyword_END
> -       keyword__LINE__
> -       keyword__FILE__
> +       keyword_return  "return"
> +       keyword_yield   "yield"
> +       keyword_super   "super"
> +       keyword_self    "self"
> +       keyword_nil     "nil"
> +       keyword_true    "true"
> +       keyword_false   "false"
> +       keyword_and     "and"
> +       keyword_or      "or"
> +       keyword_not     "not"
> +       modifier_if     "if"
> +       modifier_unless "unless"
> +       modifier_while  "while"
> +       modifier_until  "until"
> +       modifier_rescue "rescue"
> +       keyword_alias   "alias"
> +       keyword_defined "defined"
> +       keyword_BEGIN   "BEGIN"
> +       keyword_END     "END"
> +       keyword__LINE__ "__LINE__"
> +       keyword__FILE__ "__FILE__"
>  
>  %token <id>   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR tLABEL
>  %token <node> tINTEGER tFLOAT tSTRING_CONTENT tCHAR
> 
> 
> 
> #-#-#  Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University
> #-#-#  http://www.sw.it.aoyama.ac.jp       mailto:[e-mail]     
> 
>