Re: massive quotes? - Mailing list pgsql-hackers

A quick browse through the current doc set suggests that sections 4.1, 38 to
42, and the page on 'create function' at least will need changes.

I think calling it 'here-document' quoting is possibly unwise - it is
sufficiently different from here documents in shell and perl contexts to
make it confusing. We could call it meta-quoting, or alternative quoting,
maybe.

cheers

andrew


----- Original Message ----- 
From: "Tom Lane" <tgl@sss.pgh.pa.us>
To: "Sean Chittenden" <sean@chittenden.org>
Cc: "Bruce Momjian" <pgman@candle.pha.pa.us>; "Jon Jensen"
<jon@endpoint.com>; <pgsql-hackers@postgresql.org>
Sent: Sunday, September 14, 2003 1:49 AM
Subject: Re: [HACKERS] massive quotes?


> Attached is a proof-of-concept diff that makes the main SQL parser
> accept quoted strings in the style recently discussed ($Q$ ... $Q$).
> To complete the feature, we'd need to make the plpgsql parser do the
> same, update psql to understand this, update pg_dump to use this style
> of quoting for function bodies (and perhaps other things?), and update
> the documentation.  The last is a nontrivial project all by itself.
> Anybody want to run with this football?
>
> regards, tom lane
>
>
> *** src/backend/parser/scan.l.orig Sun Aug  3 23:00:44 2003
> --- src/backend/parser/scan.l Sun Sep 14 01:38:55 2003
> ***************
> *** 39,44 ****
> --- 39,46 ----
>
>   static int xcdepth = 0; /* depth of nesting in slash-star comments */
>
> + static char    *hqstart; /* current here-document start string */
> +
>   /*
>    * literalbuf is used to accumulate literal values when multiple rules
>    * are needed to parse a single literal.  Call startlit to reset buffer
> ***************
> *** 95,100 ****
> --- 97,103 ----
>    *  <xd> delimited identifiers (double-quoted identifiers)
>    *  <xh> hexadecimal numeric string
>    *  <xq> quoted strings
> +  *  <hq> here-document-style quoted strings
>    */
>
>   %x xb
> ***************
> *** 102,107 ****
> --- 105,111 ----
>   %x xd
>   %x xh
>   %x xq
> + %x hq
>
>   /* Bit string
>    * It is tempting to scan the string for only those characters
> ***************
> *** 141,146 ****
> --- 145,157 ----
>   xqoctesc [\\][0-7]{1,3}
>   xqcat {quote}{whitespace_with_newline}{quote}
>
> + /* Here-document-style quotes
> +  * The quoted string starts with $letters$ and extends to the first
occurrence
> +  * of an identical string.  There is *no* processing of the quoted text.
> +  */
> + hqdelim \$[A-Za-z]*\$
> + hqinside [^$]+
> +
>   /* Double quote
>    * Allows embedded spaces and other special characters into identifiers.
>    */
> ***************
> *** 387,392 ****
> --- 398,432 ----
>   }
>   <xq><<EOF>> { yyerror("unterminated quoted string"); }
>
> + {hqdelim} {
> + token_start = yytext;
> + hqstart = pstrdup(yytext);
> + BEGIN(hq);
> + startlit();
> + }
> + <hq>{hqdelim} {
> + if (strcmp(yytext, hqstart) == 0)
> + {
> + pfree(hqstart);
> + BEGIN(INITIAL);
> + yylval.str = litbufdup();
> + return SCONST;
> + }
> + /*
> + * When we fail to match $...$ to hqstart, transfer
> + * the $... part to the output, but put back the final
> + * $ for rescanning.  Consider $delim$...$junk$delim$
> + */
> + addlit(yytext, yyleng-1);
> + yyless(yyleng-1);
> + }
> + <hq>{hqinside}  {
> + addlit(yytext, yyleng);
> + }
> + <hq>.           {
> + addlitchar(yytext[0]);
> + }
> + <hq><<EOF>> { yyerror("unterminated special-quoted string"); }
>
>   {xdstart} {
>   token_start = yytext;
>
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