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comparison src/lex.l @ 3096:ff8b4d6371b3

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[project @ 1997-11-14 07:59:14 by jwe]
author jwe
date Fri, 14 Nov 1997 07:59:15 +0000
parents eb827eb9b8ff
children 98d862e12945
comparison
equal deleted inserted replaced
3095:528f4270e904 3096:ff8b4d6371b3
157 // 157 //
158 // will result in a call to `eye' with the argument `2'. 158 // will result in a call to `eye' with the argument `2'.
159 159
160 static int Vwhitespace_in_literal_matrix; 160 static int Vwhitespace_in_literal_matrix;
161 161
162 // Should Octave treat backslashes in strings as escapes that
163 // introduce special characters like newline (\n), tab (\t), etc.?
164 static bool Vbackslash_escapes;
162 165
163 // Forward declarations for functions defined at the bottom of this 166 // Forward declarations for functions defined at the bottom of this
164 // file. 167 // file.
165 168
166 static void do_string_escapes (char *s); 169 static void do_string_escapes (char *s);
177 static string strip_trailing_whitespace (char *s); 180 static string strip_trailing_whitespace (char *s);
178 static void handle_number (char *yytext); 181 static void handle_number (char *yytext);
179 static int handle_string (char delim, int text_style = 0); 182 static int handle_string (char delim, int text_style = 0);
180 static int handle_close_brace (int spc_gobbled); 183 static int handle_close_brace (int spc_gobbled);
181 static int handle_identifier (const string& tok, int spc_gobbled); 184 static int handle_identifier (const string& tok, int spc_gobbled);
182 static bool have_continuation (int trailing_comments_ok = 1); 185 static bool have_continuation (bool trailing_comments_ok = true);
183 static bool have_ellipsis_continuation (int trailing_comments_ok = 1); 186 static bool have_ellipsis_continuation (bool trailing_comments_ok = true);
184 static yum_yum eat_whitespace (void); 187 static yum_yum eat_whitespace (void);
185 static yum_yum eat_continuation (void); 188 static yum_yum eat_continuation (void);
186 189
187 %} 190 %}
188 191
719 // Replace backslash escapes in a string with the real values. 722 // Replace backslash escapes in a string with the real values.
720 723
721 static void 724 static void
722 do_string_escapes (char *s) 725 do_string_escapes (char *s)
723 { 726 {
727 if (! Vbackslash_escapes)
728 return;
729
724 char *p1 = s; 730 char *p1 = s;
725 char *p2 = s; 731 char *p2 = s;
726 732
727 while (*p2 != '\0') 733 while (*p2 != '\0')
728 { 734 {
1365 case '\\': 1371 case '\\':
1366 if (in_comment) 1372 if (in_comment)
1367 break; 1373 break;
1368 else 1374 else
1369 { 1375 {
1370 if (have_continuation ()) 1376 if (Vbackslash_escapes && have_continuation ())
1371 break; 1377 break;
1372 else 1378 else
1373 goto done; 1379 goto done;
1374 } 1380 }
1375 1381
1431 // Once a comment character is found, discard all input until newline. 1437 // Once a comment character is found, discard all input until newline.
1432 // If non-whitespace characters are found before comment 1438 // If non-whitespace characters are found before comment
1433 // characters, return 0. Otherwise, return 1. 1439 // characters, return 0. Otherwise, return 1.
1434 1440
1435 static bool 1441 static bool
1436 have_continuation (int trailing_comments_ok) 1442 have_continuation (bool trailing_comments_ok)
1437 { 1443 {
1438 ostrstream buf; 1444 ostrstream buf;
1439 1445
1440 bool in_comment = false; 1446 bool in_comment = false;
1441 char c; 1447 char c;
1470 } 1476 }
1471 1477
1472 yyunput (c, yytext); 1478 yyunput (c, yytext);
1473 return false; 1479 return false;
1474 1480
1475 cleanup: 1481 cleanup:
1476 buf << ends; 1482 buf << ends;
1477 char *s = buf.str (); 1483 char *s = buf.str ();
1478 if (s) 1484 if (s)
1479 { 1485 {
1480 int len = strlen (s); 1486 int len = strlen (s);
1481 while (len--) 1487 while (len--)
1482 yyunput (s[len], yytext); 1488 yyunput (s[len], yytext);
1483 } 1489 }
1484 delete [] s; 1490 delete [] s;
1491
1485 return false; 1492 return false;
1486 } 1493 }
1487 1494
1488 // We have seen a `.' and need to see if it is the start of a 1495 // We have seen a `.' and need to see if it is the start of a
1489 // continuation. If so, this eats it, up to and including the new 1496 // continuation. If so, this eats it, up to and including the new
1490 // line character. 1497 // line character.
1491 1498
1492 static bool 1499 static bool
1493 have_ellipsis_continuation (int trailing_comments_ok) 1500 have_ellipsis_continuation (bool trailing_comments_ok)
1494 { 1501 {
1495 char c1 = yyinput (); 1502 char c1 = yyinput ();
1496 if (c1 == '.') 1503 if (c1 == '.')
1497 { 1504 {
1498 char c2 = yyinput (); 1505 char c2 = yyinput ();
1519 eat_continuation (void) 1526 eat_continuation (void)
1520 { 1527 {
1521 int retval = ATE_NOTHING; 1528 int retval = ATE_NOTHING;
1522 int c = yyinput (); 1529 int c = yyinput ();
1523 if ((c == '.' && have_ellipsis_continuation ()) 1530 if ((c == '.' && have_ellipsis_continuation ())
1524 || (c == '\\' && have_continuation ())) 1531 || (c == '\\' && Vbackslash_escapes && have_continuation ()))
1525 retval = eat_whitespace (); 1532 retval = eat_whitespace ();
1526 else 1533 else
1527 yyunput (c, yytext); 1534 yyunput (c, yytext);
1528 1535
1529 return retval; 1536 return retval;
1539 1546
1540 while ((c = yyinput ()) != EOF) 1547 while ((c = yyinput ()) != EOF)
1541 { 1548 {
1542 current_input_column++; 1549 current_input_column++;
1543 1550
1544 if (c == '\\') 1551 if (c == '\\' && Vbackslash_escapes)
1545 { 1552 {
1546 if (escape_pending) 1553 if (escape_pending)
1547 { 1554 {
1548 buf << (char) c; 1555 buf << (char) c;
1549 escape_pending = 0; 1556 escape_pending = 0;
1550 } 1557 }
1551 else 1558 else
1552 { 1559 {
1553 if (have_continuation (0)) 1560 if (have_continuation (false))
1554 escape_pending = 0; 1561 escape_pending = 0;
1555 else 1562 else
1556 { 1563 {
1557 buf << (char) c; 1564 buf << (char) c;
1558 escape_pending = 1; 1565 escape_pending = 1;
1560 } 1567 }
1561 continue; 1568 continue;
1562 } 1569 }
1563 else if (c == '.') 1570 else if (c == '.')
1564 { 1571 {
1565 if (! have_ellipsis_continuation (0)) 1572 if (! have_ellipsis_continuation (false))
1566 buf << (char) c; 1573 buf << (char) c;
1567 } 1574 }
1568 else if (c == '\n') 1575 else if (c == '\n')
1569 { 1576 {
1570 error ("unterminated string constant"); 1577 error ("unterminated string constant");
1953 // Quote marks strings intially. 1960 // Quote marks strings intially.
1954 quote_is_transpose = false; 1961 quote_is_transpose = false;
1955 } 1962 }
1956 1963
1957 int 1964 int
1965 backslash_escapes (void)
1966 {
1967 Vbackslash_escapes = check_preference ("backslash_escapes");
1968
1969 return 0;
1970 }
1971
1972 int
1958 whitespace_in_literal_matrix (void) 1973 whitespace_in_literal_matrix (void)
1959 { 1974 {
1960 int pref = 0; 1975 int pref = 0;
1961 1976
1962 string val = builtin_string_variable ("whitespace_in_literal_matrix"); 1977 string val = builtin_string_variable ("whitespace_in_literal_matrix");
1975 } 1990 }
1976 1991
1977 void 1992 void
1978 symbols_of_lex (void) 1993 symbols_of_lex (void)
1979 { 1994 {
1995 DEFVAR (backslash_escapes, 1.0, 0, backslash_escapes,
1996 "if nonzero, Octave recognizes backslashes in strings as escapes that\n\
1997 introduce special characters like newline (\\n), tab (\\t), etc.");
1998
1980 DEFVAR (whitespace_in_literal_matrix, "", 0, whitespace_in_literal_matrix, 1999 DEFVAR (whitespace_in_literal_matrix, "", 0, whitespace_in_literal_matrix,
1981 "control auto-insertion of commas and semicolons in literal matrices"); 2000 "control auto-insertion of commas and semicolons in literal matrices");
1982 } 2001 }
1983 2002
1984 /* 2003 /*