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Support parametric types.

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There are two issues to handle: first scanning nested angle bracket pairs
to support types such as std::pair< std::string, std::list<std::string> > >.

Another issue is to address idiosyncracies of C++: do not glue two closing
angle brackets together (otherwise it's operator>>), and avoid sticking
blindly a TYPE to the opening <, as it can result in '<:' which is a
digraph for '['.

	* src/scan-gram.l (brace_level): Rename as...
	(nesting): this.
	(SC_TAG): New.
	Implement support for complex tags.
	(tag): Accept \n, but not <.
	* data/lalr1.cc (b4_symbol_value, b4_symbol_value_template)
	(b4_symbol_variant): Leave space around types as parameters.
	* examples/variant.yy: Use nested template types and leading ::.
	* src/parse-gram.y (TYPE, TYPE_TAG_ANY, TYPE_TAG_NONE, type.opt):
	Rename as...
	(TAG, TAG_ANY, TAG_NONE, tag.opt): these.
	* tests/c++.at: Test parametric types.
This commit is contained in:
Akim Demaille
2008-10-23 20:01:48 -05:00
parent 7b6e67533e
commit cb823b6f0c
6 changed files with 128 additions and 48 deletions
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82
src/scan-gram.l
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@@ -78,6 +78,8 @@ static void unexpected_newline (boundary, char const *);
/* A identifier was just read in directives/rules. Special state
to capture the sequence `identifier :'. */
%x SC_AFTER_IDENTIFIER
/* A complex tag, with nested angles brackets. */
%x SC_TAG
/* Three types of user code:
- prologue (code between `%{' `%}' in the first section, before %%);
@@ -96,8 +98,10 @@ int [0-9]+
/* POSIX says that a tag must be both an id and a C union member, but
historically almost any character is allowed in a tag. We disallow
NUL and newline, as this simplifies our implementation. */
tag [^\0\n>]+
NUL, as this simplifies our implementation. We disallow angle
bracket to match them in nested pairs: several languages use them
for generics/template types. */
tag [^\0<>]+
/* Zero or more instances of backslash-newline. Following GCC, allow
white space between the backslash and the newline. */
@@ -105,8 +109,9 @@ splice (\\[ \f\t\v]*\n)*
%%
%{
/* Nesting level of the current code in braces. */
int braces_level IF_LINT (= 0);
/* Nesting level. Either for nested braces, or nested angle brackets
(but not mixed). */
int nesting IF_LINT (= 0);
/* Parent context state, when applicable. */
int context_state IF_LINT (= 0);
@@ -205,8 +210,6 @@ splice (\\[ \f\t\v]*\n)*
"=" return EQUAL;
"|" return PIPE;
";" return SEMICOLON;
"<*>" return TYPE_TAG_ANY;
"<>" return TYPE_TAG_NONE;
{id} {
val->uniqstr = uniqstr_new (yytext);
@@ -235,18 +238,25 @@ splice (\\[ \f\t\v]*\n)*
/* Code in between braces. */
"{" {
STRING_GROW;
braces_level = 0;
nesting = 0;
code_start = loc->start;
BEGIN SC_BRACED_CODE;
}
/* A type. */
"<*>" return TAG_ANY;
"<>" return TAG_NONE;
"<"{tag}">" {
obstack_grow (&obstack_for_string, yytext + 1, yyleng - 2);
STRING_FINISH;
val->uniqstr = uniqstr_new (last_string);
STRING_FREE;
return TYPE;
return TAG;
}
"<" {
nesting = 0;
token_start = loc->start;
BEGIN SC_TAG;
}
"%%" {
@@ -267,6 +277,17 @@ splice (\\[ \f\t\v]*\n)*
}
/*--------------------------------------------------------------.
| Supporting \0 complexifies our implementation for no expected |
| added value. |
`--------------------------------------------------------------*/
<SC_ESCAPED_CHARACTER,SC_ESCAPED_STRING,SC_TAG>
{
\0 complain_at (*loc, _("invalid null character"));
}
/*-----------------------------------------------------------------.
| Scanning after an identifier, checking whether a colon is next. |
`-----------------------------------------------------------------*/
@@ -386,11 +407,40 @@ splice (\\[ \f\t\v]*\n)*
}
}
<SC_ESCAPED_CHARACTER,SC_ESCAPED_STRING>
{
\0 complain_at (*loc, _("invalid null character"));
}
/*-----------------------------------------------------------.
| Scanning a Bison nested tag. The initial angle bracket is |
| already eaten. |
`-----------------------------------------------------------*/
<SC_TAG>
{
">" {
--nesting;
if (nesting < 0)
{
STRING_FINISH;
loc->start = token_start;
val->uniqstr = uniqstr_new (last_string);
STRING_FREE;
BEGIN INITIAL;
return TAG;
}
STRING_GROW;
}
[^<>]+ STRING_GROW;
"<"+ STRING_GROW; nesting += yyleng;
<<EOF>> {
unexpected_eof (token_start, ">");
STRING_FINISH;
loc->start = token_start;
val->uniqstr = uniqstr_new (last_string);
STRING_FREE;
BEGIN INITIAL;
return TAG;
}
}
/*----------------------------.
| Decode escaped characters. |
@@ -509,13 +559,13 @@ splice (\\[ \f\t\v]*\n)*
<SC_BRACED_CODE>
{
"{"|"<"{splice}"%" STRING_GROW; braces_level++;
"%"{splice}">" STRING_GROW; braces_level--;
"{"|"<"{splice}"%" STRING_GROW; nesting++;
"%"{splice}">" STRING_GROW; nesting--;
"}" {
obstack_1grow (&obstack_for_string, '}');
--braces_level;
if (braces_level < 0)
--nesting;
if (nesting < 0)
{
STRING_FINISH;
loc->start = code_start;