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Commit559a287

Browse files
author
Thomas G. Lockhart
committed
Use exclusive states for parsing quoted strings.
Implement extended comments ("/* ... */") using exclusive states.Modify definitions of operators to remove some restrictions on characters and character order.
1 parent1370a08 commit559a287

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1 file changed

+106
-56
lines changed

1 file changed

+106
-56
lines changed

‎src/backend/parser/scan.l

Lines changed: 106 additions & 56 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/parser/scan.l,v 1.14 1997/08/20 01:50:06 vadim Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/parser/scan.l,v 1.15 1997/09/01 05:51:52 thomas Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -59,7 +59,42 @@ void unput(char);
5959
#endif/* FLEX_SCANNER*/
6060

6161
extern YYSTYPE yylval;
62+
63+
int llen;
64+
char literal[MAX_PARSE_BUFFER];
65+
6266
%}
67+
/* OK, here is a short description of lex/flex rules behavior.
68+
* The longest pattern which matches an input string is always chosen.
69+
* For equal-length patterns, the first occurring in the rules list is chosen.
70+
* INITIAL is the starting condition, to which all non-conditional rules apply.
71+
* <xc> is an exclusive condition to allow embedded C-style comments.
72+
* When in an exclusive condition, only those rules defined for that condition apply.
73+
* So, when in condition <xc>, only strings which would terminate the "extended comment"
74+
* trigger any action other than "ignore".
75+
* The "extended comment" syntax closely resembles allowable operator syntax.
76+
* Therefore, be sure to match _any_ candidate comment, including those with appended
77+
* operator-like symbols. - thomas 1997-07-14
78+
*/
79+
80+
/* define an exclusive condition to allow extended C-style comments - tgl 1997-07-12 */
81+
%xxc
82+
/* define an exclusive condition for quoted strings - tgl 1997-07-30 */
83+
%xxq
84+
85+
/* We used to allow double-quoted strings, but SQL doesn't so we won't either */
86+
quote '
87+
xqstart{quote}
88+
xqstop{quote}
89+
xqdouble{quote}{quote}
90+
xqinside[^\']*
91+
xqliteral[\\].
92+
93+
xcline[\/][\*].*[\*][\/]{space}*\n*
94+
xcstart[\/][\*]{op_and_self}*
95+
xcstop{op_and_self}*[\*][\/]({space}*|\n)
96+
xcinside[^*]*
97+
xcstar[^/]
6398

6499
digit[0-9]
65100
letter[_A-Za-z]
@@ -69,15 +104,15 @@ sysfuncSYS_{letter}{letter_or_digit}*
69104

70105
identifier{letter}{letter_or_digit}*
71106

107+
typecast"::"
108+
72109
self[,()\[\].;$\:\+\-\*\/\<\>\=\|]
110+
selfm{self}[\-][\.0-9]
111+
73112
op_and_self[\~\!\@\#\%\^\&\|\`\?\$\:\+\-\*\/\<\>\=]
74-
op_and_self2[\~\!\@\#\%\^\&\|\`\?\$\:\*\/\<\>\=]
75-
op_only[\~\!\@\#\%\^\&\`\?]
76113

77-
operator({op_and_self}{op_and_self2}+)|{op_only}+
78-
/* we used to allow double-quoted strings, but SQL doesn't */
79-
/* so we won't either*/
80-
quote '
114+
operator{op_and_self}+
115+
operatorm{op_and_self}+[\-][\.0-9]
81116

82117
integer-?{digit}+
83118
real-?{digit}+\.{digit}+([Ee][-+]?{digit}+)?
@@ -97,10 +132,57 @@ other.
97132

98133
{comment}{/* ignore */}
99134

100-
"::"{return TYPECAST;}
135+
/* allow extended comments using C-style delimiters - tgl 1997-07-12 */
136+
{xcline}{/* ignore */ }
137+
138+
<xc>{xcstar}|
139+
{xcstart}{BEGIN(xc); }
101140

102-
{self}{return (yytext[0]);}
141+
<xc>{xcstop}{BEGIN(INITIAL);}
103142

143+
<xc>{xcinside}{/* ignore */ }
144+
145+
{xqstart}{
146+
BEGIN(xq);
147+
llen =0;
148+
*literal ='\0';
149+
}
150+
<xq>{xqstop}{
151+
BEGIN(INITIAL);
152+
yylval.str =pstrdup(scanstr(literal));
153+
return (SCONST);
154+
}
155+
<xq>{xqdouble}|
156+
<xq>{xqinside}{
157+
if ((llen+yyleng) > (MAX_PARSE_BUFFER -1)) {
158+
elog(WARN,"quoted string parse buffer of %d chars exceeded",MAX_PARSE_BUFFER);
159+
/* not reached */
160+
}
161+
memcpy(literal+llen, yytext, yyleng+1);
162+
llen += yyleng;
163+
}
164+
<xq>{xqliteral}{
165+
if ((llen+yyleng-1) > (MAX_PARSE_BUFFER -1)) {
166+
elog(WARN,"quoted string parse buffer of %d chars exceeded",MAX_PARSE_BUFFER);
167+
/* not reached */
168+
}
169+
memcpy(literal+llen, yytext+1, yyleng);
170+
llen += yyleng-1;
171+
}
172+
173+
{typecast}{return TYPECAST; }
174+
175+
{selfm}{
176+
yyless(yyleng-2);
177+
return (yytext[0]);
178+
}
179+
{self}{return (yytext[0]); }
180+
181+
{operatorm}{
182+
yyless(yyleng-2);
183+
yylval.str =pstrdup((char*)yytext);
184+
return (Op);
185+
}
104186
{operator}{
105187
if (strcmp((char*)yytext,"!=") ==0)
106188
yylval.str =pstrdup("<>");/* compatability */
@@ -124,49 +206,6 @@ other.
124206
CheckFloat8Val(yylval.dval);
125207
return (FCONST);
126208
}
127-
{quote} {
128-
char literal[MAX_PARSE_BUFFER];
129-
int i =0;
130-
int c =0;
131-
/* quote_seen can be either \ or ' because
132-
we handle both cases of \' and '' for
133-
quoting quotes*/
134-
int quote_seen =0;
135-
136-
while (i < MAX_PARSE_BUFFER -1) {
137-
c =input();
138-
if (quote_seen !=0) {
139-
if (quote_seen =='\'' &&
140-
c !='\'') {
141-
/* a non-quote follows a single quote */
142-
/* so we've hit the end of the literal */
143-
if (c !='\0' && c != EOF)
144-
unput(c);/* put back the extra char we read*/
145-
i = i -1;
146-
break;/* break out of the while loop */
147-
}
148-
/* if we reach here, we're still in */
149-
/* the string literal */
150-
literal[i++] = c;
151-
quote_seen =0;
152-
continue;
153-
}
154-
if (c =='\0' || c == EOF) {
155-
elog(WARN,"unterminated quoted string literal");
156-
/* not reached */
157-
}
158-
literal[i++] = c;
159-
if (c =='\'' || c =='\\')
160-
quote_seen = c;
161-
}
162-
if ( i == MAX_PARSE_BUFFER -1) {
163-
elog (WARN,"unterminated quote string. parse buffer of %d chars exceeded", MAX_PARSE_BUFFER);
164-
/* not reached */
165-
}
166-
literal[i] ='\0';
167-
yylval.str =pstrdup(scanstr(literal));
168-
return (SCONST);
169-
}
170209
{identifier}{
171210
int i;
172211
ScanKeyword*keyword;
@@ -177,19 +216,25 @@ other.
177216

178217
keyword =ScanKeywordLookup((char*)yytext);
179218
if (keyword !=NULL) {
180-
if ( keyword->value == DEFAULT )
219+
if ( keyword->value == DEFAULT ) {
181220
DefaultStartPosition =CurScanPosition () + yyleng +1;
182-
elseif ( keyword->value == CHECK )
221+
printf("default offset is %d\n", DefaultStartPosition);
222+
223+
}elseif ( keyword->value == CHECK ) {
183224
CheckStartPosition =CurScanPosition () + yyleng +1;
225+
printf("check offset is %d\n", CheckStartPosition);
226+
227+
};
228+
184229
return (keyword->value);
185230
}else {
186231
yylval.str =pstrdup((char*)yytext);
187232
return (IDENT);
188233
}
189234
}
190-
{space}{/* ignore */}
235+
{space}{/* ignore */}
191236

192-
{other}{return (yytext[0]);}
237+
{other}{return (yytext[0]);}
193238

194239
%%
195240

@@ -282,7 +327,12 @@ myinput(char* buf, int max)
282327
int
283328
CurScanPosition(void)
284329
{
330+
printf("current position is %d\n", yy_c_buf_p - yy_current_buffer->yy_ch_buf - yyleng);
331+
332+
return (parseCh - parseString - yyleng -1);
333+
#if FALSE
285334
return (yy_c_buf_p - yy_current_buffer->yy_ch_buf - yyleng);
335+
#endif
286336
}
287337

288338
#endif/* FLEX_SCANNER */

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