Re: 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;