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Remove stack option. We no longer use the stack, since the stack was

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never deeper than 1; instead, use the new auto var c_context to record
the stacked value.

Remove nounput option.  At an unexpected end of file, we now unput
the minimal input necessary to end cleanly; this simplifies the
code.

Avoid unbounded token sizes where this is easy.

(unexpected_end_of_file): New function.
Use it to systematize the error message on unexpected EOF.
(last-string): Now auto, not static.
(YY_OBS_FREE): Remove unnecessary do while (0) wrapper.
(scanner_last_string_free): Remove; not used.
(percent_percent_count): Move decl to just before use.
(SC_ESCAPED_CHARACTER): Return ID at unexpected end of file,
not the (never otherwised-used) CHARACTER.
This commit is contained in:
Paul Eggert
2002-11-08 05:20:20 +00:00
parent 87fbb0bffc
commit a706a1cc03
1 changed files with 89 additions and 170 deletions
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259
src/scan-gram.l
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@@ -19,7 +19,7 @@
02111-1307 USA 02111-1307 USA
*/ */
%option debug nodefault noyywrap nounput never-interactive stack %option debug nodefault noyywrap never-interactive
%option prefix="gram_" outfile="lex.yy.c" %option prefix="gram_" outfile="lex.yy.c"
%{ %{
@@ -129,19 +129,6 @@ extend_location (location_t *loc, char const *token, int size)
} }
/* Report an unexpected end of file at LOC. A token or comment began
with TOKEN_START, but an end of file was encountered and the
expected TOKEN_END was missing. */
static void
unexpected_end_of_file (location_t loc,
char const *token_start, char const *token_end)
{
complain_at (loc, _("unexpected end of file in `%s ... %s'"),
token_start, token_end);
}
/* STRING_OBSTACK -- Used to store all the characters that we need to /* STRING_OBSTACK -- Used to store all the characters that we need to
keep (to construct ID, STRINGS etc.). Use the following macros to keep (to construct ID, STRINGS etc.). Use the following macros to
@@ -153,7 +140,6 @@ unexpected_end_of_file (location_t loc,
used, and which is used by YY_OBS_FREE to free the last string. */ used, and which is used by YY_OBS_FREE to free the last string. */
static struct obstack string_obstack; static struct obstack string_obstack;
char *last_string;
#define YY_OBS_GROW \ #define YY_OBS_GROW \
obstack_grow (&string_obstack, yytext, yyleng) obstack_grow (&string_obstack, yytext, yyleng)
@@ -164,19 +150,9 @@ char *last_string;
last_string = obstack_finish (&string_obstack); \ last_string = obstack_finish (&string_obstack); \
} while (0) } while (0)
#define YY_OBS_FREE \ #define YY_OBS_FREE \
do { \ obstack_free (&string_obstack, last_string)
obstack_free (&string_obstack, last_string); \
} while (0)
void
scanner_last_string_free (void)
{
YY_OBS_FREE;
}
static int percent_percent_count = 0;
/* Within well-formed rules, RULE_LENGTH is the number of values in /* Within well-formed rules, RULE_LENGTH is the number of values in
the current rule so far, which says where to find `$0' with respect the current rule so far, which says where to find `$0' with respect
@@ -192,6 +168,7 @@ static void handle_at (braced_code_t code_kind,
char *cp, location_t location); char *cp, location_t location);
static void handle_syncline (char *args, location_t *location); static void handle_syncline (char *args, location_t *location);
static int convert_ucn_to_byte (char const *hex_text); static int convert_ucn_to_byte (char const *hex_text);
static void unexpected_end_of_file (location_t, char const *);
%} %}
%x SC_COMMENT SC_LINE_COMMENT SC_YACC_COMMENT %x SC_COMMENT SC_LINE_COMMENT SC_YACC_COMMENT
@@ -215,8 +192,15 @@ splice (\\[ \f\t\v]*\n)*
%% %%
%{ %{
/* Nesting level of the current code in braces. */
int braces_level IF_LINT (= 0); int braces_level IF_LINT (= 0);
/* Scanner context when scanning C code. */
int c_context IF_LINT (= 0);
/* A string representing the most recently saved token. */
char *last_string;
/* At each yylex invocation, mark the current position as the /* At each yylex invocation, mark the current position as the
start of the next token. */ start of the next token. */
YY_STEP; YY_STEP;
@@ -276,7 +260,7 @@ splice (\\[ \f\t\v]*\n)*
"," return COMMA; "," return COMMA;
";" return SEMICOLON; ";" return SEMICOLON;
[ \f\n\t\v]+ YY_STEP; [ \f\n\t\v] YY_STEP;
{id} { {id} {
yylval->symbol = symbol_get (yytext, *yylloc); yylval->symbol = symbol_get (yytext, *yylloc);
@@ -298,20 +282,20 @@ splice (\\[ \f\t\v]*\n)*
} }
/* Characters. We don't check there is only one. */ /* Characters. We don't check there is only one. */
"'" YY_OBS_GROW; yy_push_state (SC_ESCAPED_CHARACTER); "'" YY_OBS_GROW; BEGIN SC_ESCAPED_CHARACTER;
/* Strings. */ /* Strings. */
"\"" YY_OBS_GROW; yy_push_state (SC_ESCAPED_STRING); "\"" YY_OBS_GROW; BEGIN SC_ESCAPED_STRING;
/* Comments. */ /* Comments. */
"/*" BEGIN SC_YACC_COMMENT; "/*" BEGIN SC_YACC_COMMENT;
"//".* YY_STEP; "//".* YY_STEP;
/* Prologue. */ /* Prologue. */
"%{" yy_push_state (SC_PROLOGUE); "%{" BEGIN SC_PROLOGUE;
/* Code in between braces. */ /* Code in between braces. */
"{" YY_OBS_GROW; braces_level = 0; yy_push_state (SC_BRACED_CODE); "{" YY_OBS_GROW; braces_level = 0; BEGIN SC_BRACED_CODE;
/* A type. */ /* A type. */
"<"{tag}">" { "<"{tag}">" {
@@ -321,33 +305,20 @@ splice (\\[ \f\t\v]*\n)*
return TYPE; return TYPE;
} }
"%%" {
"%%" { static int percent_percent_count;
if (++percent_percent_count == 2) if (++percent_percent_count == 2)
yy_push_state (SC_EPILOGUE); BEGIN SC_EPILOGUE;
return PERCENT_PERCENT; return PERCENT_PERCENT;
} }
. { . {
complain_at (*yylloc, _("invalid character: %s"), quote (yytext)); complain_at (*yylloc, _("invalid character: %s"), quote (yytext));
YY_STEP; YY_STEP;
} }
} }
/*-------------------------------------------------------------------.
| Whatever the start condition (but those which correspond to |
| entities `swallowed' by Bison: SC_YACC_COMMENT, SC_ESCAPED_STRING, |
| and SC_ESCAPED_CHARACTER), no M4 character must escape as is. |
`-------------------------------------------------------------------*/
<SC_COMMENT,SC_LINE_COMMENT,SC_STRING,SC_CHARACTER,SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>
{
\[ obstack_sgrow (&string_obstack, "@<:@");
\] obstack_sgrow (&string_obstack, "@:>@");
}
/*---------------------------------------------------------------. /*---------------------------------------------------------------.
| Scanning a Yacc comment. The initial `/ *' is already eaten. | | Scanning a Yacc comment. The initial `/ *' is already eaten. |
`---------------------------------------------------------------*/ `---------------------------------------------------------------*/
@@ -359,12 +330,8 @@ splice (\\[ \f\t\v]*\n)*
BEGIN INITIAL; BEGIN INITIAL;
} }
[^*]+|"*" ; .|\n ;
<<EOF>> unexpected_end_of_file (*yylloc, "*/");
<<EOF>> {
unexpected_end_of_file (*yylloc, "/*", "*/");
BEGIN INITIAL;
}
} }
@@ -374,13 +341,8 @@ splice (\\[ \f\t\v]*\n)*
<SC_COMMENT> <SC_COMMENT>
{ {
"*"{splice}"/" YY_OBS_GROW; yy_pop_state (); "*"{splice}"/" YY_OBS_GROW; BEGIN c_context;
[^*\[\]]+|"*" YY_OBS_GROW; <<EOF>> unexpected_end_of_file (*yylloc, "*/");
<<EOF>> {
unexpected_end_of_file (*yylloc, "/*", "*/");
yy_pop_state ();
}
} }
@@ -390,9 +352,9 @@ splice (\\[ \f\t\v]*\n)*
<SC_LINE_COMMENT> <SC_LINE_COMMENT>
{ {
"\n" YY_OBS_GROW; yy_pop_state (); "\n" YY_OBS_GROW; BEGIN c_context;
([^\n\[\]]|{splice})+ YY_OBS_GROW; {splice} YY_OBS_GROW;
<<EOF>> yy_pop_state (); <<EOF>> BEGIN c_context;
} }
@@ -404,25 +366,16 @@ splice (\\[ \f\t\v]*\n)*
<SC_ESCAPED_STRING> <SC_ESCAPED_STRING>
{ {
"\"" { "\"" {
assert (yy_top_state () == INITIAL);
YY_OBS_GROW; YY_OBS_GROW;
YY_OBS_FINISH; YY_OBS_FINISH;
yylval->string = last_string; yylval->string = last_string;
yy_pop_state ();
rule_length++; rule_length++;
BEGIN INITIAL;
return STRING; return STRING;
} }
[^\"\\]+ YY_OBS_GROW; .|\n YY_OBS_GROW;
<<EOF>> unexpected_end_of_file (*yylloc, "\"");
<<EOF>> {
unexpected_end_of_file (*yylloc, "\"", "\"");
assert (yy_top_state () == INITIAL);
YY_OBS_FINISH;
yylval->string = last_string;
yy_pop_state ();
return STRING;
}
} }
/*---------------------------------------------------------------. /*---------------------------------------------------------------.
@@ -434,30 +387,19 @@ splice (\\[ \f\t\v]*\n)*
{ {
"'" { "'" {
YY_OBS_GROW; YY_OBS_GROW;
assert (yy_top_state () == INITIAL);
{
YY_OBS_FINISH;
yylval->symbol = symbol_get (last_string, *yylloc);
symbol_class_set (yylval->symbol, token_sym, *yylloc);
symbol_user_token_number_set (yylval->symbol,
(unsigned char) last_string[1], *yylloc);
YY_OBS_FREE;
yy_pop_state ();
rule_length++;
return ID;
}
}
[^\'\\]+ YY_OBS_GROW;
<<EOF>> {
unexpected_end_of_file (*yylloc, "'", "'");
assert (yy_top_state () == INITIAL);
YY_OBS_FINISH; YY_OBS_FINISH;
yylval->string = last_string; yylval->symbol = symbol_get (last_string, *yylloc);
yy_pop_state (); symbol_class_set (yylval->symbol, token_sym, *yylloc);
return CHARACTER; symbol_user_token_number_set (yylval->symbol,
(unsigned char) last_string[1], *yylloc);
YY_OBS_FREE;
rule_length++;
BEGIN INITIAL;
return ID;
} }
.|\n YY_OBS_GROW;
<<EOF>> unexpected_end_of_file (*yylloc, "'");
} }
@@ -517,8 +459,6 @@ splice (\\[ \f\t\v]*\n)*
quote (yytext)); quote (yytext));
YY_OBS_GROW; YY_OBS_GROW;
} }
/* FLex wants this rule, in case of a `\<<EOF>>'. */
\\ YY_OBS_GROW;
} }
@@ -529,23 +469,10 @@ splice (\\[ \f\t\v]*\n)*
<SC_CHARACTER> <SC_CHARACTER>
{ {
"'" { "'" YY_OBS_GROW; BEGIN c_context;
YY_OBS_GROW;
assert (yy_top_state () != INITIAL);
yy_pop_state ();
}
[^'\[\]\\]+ YY_OBS_GROW;
\\{splice}[^\[\]] YY_OBS_GROW; \\{splice}[^\[\]] YY_OBS_GROW;
{splice} YY_OBS_GROW; {splice} YY_OBS_GROW;
/* Needed for `\<<EOF>>', `\\<<newline>>[', and `\\<<newline>>]'. */ <<EOF>> unexpected_end_of_file (*yylloc, "'");
\\ YY_OBS_GROW;
<<EOF>> {
unexpected_end_of_file (*yylloc, "'", "'");
assert (yy_top_state () != INITIAL);
yy_pop_state ();
}
} }
@@ -556,23 +483,10 @@ splice (\\[ \f\t\v]*\n)*
<SC_STRING> <SC_STRING>
{ {
"\"" { "\"" YY_OBS_GROW; BEGIN c_context;
assert (yy_top_state () != INITIAL);
YY_OBS_GROW;
yy_pop_state ();
}
[^\"\[\]\\]+ YY_OBS_GROW;
\\{splice}[^\[\]] YY_OBS_GROW; \\{splice}[^\[\]] YY_OBS_GROW;
{splice} YY_OBS_GROW; {splice} YY_OBS_GROW;
/* Needed for `\<<EOF>>', `\\<<newline>>[', and `\\<<newline>>]'. */ <<EOF>> unexpected_end_of_file (*yylloc, "\"");
\\ YY_OBS_GROW;
<<EOF>> {
unexpected_end_of_file (*yylloc, "\"", "\"");
assert (yy_top_state () != INITIAL);
yy_pop_state ();
}
} }
@@ -582,18 +496,10 @@ splice (\\[ \f\t\v]*\n)*
<SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE> <SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>
{ {
/* Characters. We don't check there is only one. */ "'" YY_OBS_GROW; c_context = YY_START; BEGIN SC_CHARACTER;
"'" YY_OBS_GROW; yy_push_state (SC_CHARACTER); "\"" YY_OBS_GROW; c_context = YY_START; BEGIN SC_STRING;
"/"{splice}"*" YY_OBS_GROW; c_context = YY_START; BEGIN SC_COMMENT;
/* Strings. */ "/"{splice}"/" YY_OBS_GROW; c_context = YY_START; BEGIN SC_LINE_COMMENT;
"\"" YY_OBS_GROW; yy_push_state (SC_STRING);
/* Comments. */
"/"{splice}"*" YY_OBS_GROW; yy_push_state (SC_COMMENT);
"/"{splice}"/" YY_OBS_GROW; yy_push_state (SC_LINE_COMMENT);
/* Not comments. */
"/" YY_OBS_GROW;
} }
@@ -611,31 +517,24 @@ splice (\\[ \f\t\v]*\n)*
braces_level--; braces_level--;
if (braces_level < 0) if (braces_level < 0)
{ {
yy_pop_state ();
YY_OBS_FINISH; YY_OBS_FINISH;
yylval->string = last_string; yylval->string = last_string;
rule_length++; rule_length++;
BEGIN INITIAL;
return BRACED_CODE; return BRACED_CODE;
} }
} }
/* Tokenize `<<%' correctly (as `<<' `%') rather than incorrrectly
(as `<' `<%'). */
"<"{splice}"<" YY_OBS_GROW;
"$"("<"{tag}">")?(-?[0-9]+|"$") { handle_dollar (current_braced_code, "$"("<"{tag}">")?(-?[0-9]+|"$") { handle_dollar (current_braced_code,
yytext, *yylloc); } yytext, *yylloc); }
"@"(-?[0-9]+|"$") { handle_at (current_braced_code, "@"(-?[0-9]+|"$") { handle_at (current_braced_code,
yytext, *yylloc); } yytext, *yylloc); }
/* `"<"{splice}"<"' tokenizes `<<%' correctly (as `<<' `%') rather <<EOF>> unexpected_end_of_file (*yylloc, "}");
than incorrrectly (as `<' `<%'). */
[^\"$%\'/<@\[\]\{\}]+|[$%/<@]|"<"{splice}"<" YY_OBS_GROW;
<<EOF>> {
unexpected_end_of_file (*yylloc, "{", "}");
yy_pop_state ();
YY_OBS_FINISH;
yylval->string = last_string;
return BRACED_CODE;
}
} }
@@ -646,22 +545,13 @@ splice (\\[ \f\t\v]*\n)*
<SC_PROLOGUE> <SC_PROLOGUE>
{ {
"%}" { "%}" {
yy_pop_state ();
YY_OBS_FINISH; YY_OBS_FINISH;
yylval->string = last_string; yylval->string = last_string;
BEGIN INITIAL;
return PROLOGUE; return PROLOGUE;
} }
[^%\[\]/\'\"]+ YY_OBS_GROW; <<EOF>> unexpected_end_of_file (*yylloc, "%}");
"%" YY_OBS_GROW;
<<EOF>> {
unexpected_end_of_file (*yylloc, "%{", "%}");
yy_pop_state ();
YY_OBS_FINISH;
yylval->string = last_string;
return PROLOGUE;
}
} }
@@ -672,17 +562,28 @@ splice (\\[ \f\t\v]*\n)*
<SC_EPILOGUE> <SC_EPILOGUE>
{ {
[^\[\]]+ YY_OBS_GROW;
<<EOF>> { <<EOF>> {
yy_pop_state ();
YY_OBS_FINISH; YY_OBS_FINISH;
yylval->string = last_string; yylval->string = last_string;
BEGIN INITIAL;
return EPILOGUE; return EPILOGUE;
} }
} }
/*----------------------------------------------------------------.
| By default, grow the string obstack with the input, escaping M4 |
| quoting characters. |
`----------------------------------------------------------------*/
<SC_COMMENT,SC_LINE_COMMENT,SC_STRING,SC_CHARACTER,SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>
{
\[ obstack_sgrow (&string_obstack, "@<:@");
\] obstack_sgrow (&string_obstack, "@:>@");
.|\n YY_OBS_GROW;
}
%% %%
/*------------------------------------------------------------------. /*------------------------------------------------------------------.
@@ -933,6 +834,24 @@ handle_syncline (char *args, location_t *location)
location->last_line = lineno; location->last_line = lineno;
} }
/*-------------------------------------------------------------.
| Report an unexpected end of file at LOC. An end of file was |
| encountered and the expected TOKEN_END was missing. After |
| reporting the problem, pretend that TOKEN_END was found. |
`-------------------------------------------------------------*/
static void
unexpected_end_of_file (location_t loc, char const *token_end)
{
size_t i;
complain_at (loc, _("missing `%s' at end of file"), token_end);
for (i = strlen (token_end); i != 0; i--)
unput (token_end[i - 1]);
}
/*-------------------------. /*-------------------------.
| Initialize the scanner. | | Initialize the scanner. |
`-------------------------*/ `-------------------------*/