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* src/ltlparse/ltlparse.yy (OP_POST_NEG, OP_POST_POS): New tokens.

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(subformula): Recognize `ATOMIC_PROP OP_POST_POS' and
`ATOMIC_PROP OP_POST_NEG'.
* src/ltlparse/ltlscan.ll: Introduce the not_prop start condition,
to restrict the set of atomic propositions allowed in places
where they are not expected.  Make `true' and `false' case insensitive.
* src/ltltest/parse.test, src/ltltest/tostring.test: More cases.
* src/ltlvisit/tostring.cc (to_string_visitor): Quote atomic
propositions equal to "true" or "false".
This commit is contained in:
Alexandre Duret-Lutz 2004-05-13 09:49:06 +00:00
parent 4f96a9fc14
commit 60a3b4ed72
6 changed files with 125 additions and 34 deletions
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88
src/ltlparse/ltlscan.ll
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@ -1,4 +1,4 @@
/* Copyright (C) 2003 Laboratoire d'Informatique de Paris 6 (LIP6),
/* Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
** département Systèmes Répartis Coopératifs (SRC), Université Pierre
** et Marie Curie.
**
@ -51,57 +51,87 @@ flex_set_buffer(const char* buf)
%}
%s not_prop
%%
%{
yylloc->step();
%}
"(" return PAR_OPEN;
")" return PAR_CLOSE;
"(" BEGIN(0); return PAR_OPEN;
")" BEGIN(not_prop); return PAR_CLOSE;
/* Must go before the other operators, because the F of FALSE
should not be mistaken with a unary F. */
"1"|[tT][rR][uU][eE] BEGIN(0); return CONST_TRUE;
"0"|[fF][aA][lL][sS][eE] BEGIN(0); return CONST_FALSE;
"!" BEGIN(0); return OP_NOT;
"!" return OP_NOT;
/* & and | come from Spin. && and || from LTL2BA.
/\, \/, and xor are from LBTT.
*/
"||"|"|"|"+"|"\\/" return OP_OR;
"&&"|"&"|"."|"*"|"/\\" return OP_AND;
"^"|"xor" return OP_XOR;
"=>"|"->" return OP_IMPLIES;
"<=>"|"<->" return OP_EQUIV;
"||"|"|"|"+"|"\\/" BEGIN(0); return OP_OR;
"&&"|"&"|"."|"*"|"/\\" BEGIN(0); return OP_AND;
"^"|"xor" BEGIN(0); return OP_XOR;
"=>"|"->" BEGIN(0); return OP_IMPLIES;
"<=>"|"<->" BEGIN(0); return OP_EQUIV;
/* <>, [], and () are used in Spin. */
"F"|"<>" return OP_F;
"G"|"[]" return OP_G;
"U" return OP_U;
"R"|"V" return OP_R;
"X"|"()" return OP_X;
"F"|"<>" BEGIN(0); return OP_F;
"G"|"[]" BEGIN(0); return OP_G;
"U" BEGIN(0); return OP_U;
"R"|"V" BEGIN(0); return OP_R;
"X"|"()" BEGIN(0); return OP_X;
"1"|"true" return CONST_TRUE;
"0"|"false" return CONST_FALSE;
"=0" return OP_POST_NEG;
"=1" return OP_POST_POS;
[ \t\n]+ /* discard whitespace */ yylloc->step ();
[ \t\n]+ /* discard whitespace */ yylloc->step ();
/* An Atomic proposition cannot start with the letter
used by a unary operator (F,G,X), unless this
letter is followed by a digit in which case we assume
it's an ATOMIC_PROP (even though F0 could be seen as Ffalse, we
don't). */
[a-zA-EH-WYZ_][a-zA-Z0-9_]* |
[FGX][0-9_][a-zA-Z0-9_]* {
yylval->str = new std::string(yytext);
return ATOMIC_PROP;
}
don't).
*/
<INITIAL>[a-zA-EH-WYZ_][a-zA-Z0-9_]* |
<INITIAL>[FGX][0-9_][a-zA-Z0-9_]* |
/*
However if we have just parsed an atomic proposition, then we
are not expecting another atomic proposition, so we can be stricter
and disallow propositions that start with U, R and V. If you wonder
why we do this, consider the Wring formula `p=0Uq=1'. When p is
parsed, we enter the not_prop start condition, we remain into this
condition when `=0' is processed, and then because we are in this
condition we will not consider `Uq' as an atomic proposition but as
a `U' operator followed by a `q' atomic proposition.
We also disable atomic proposition that may look a combination
of a binary operator followed by several unary operators.
E.g. UFXp. This way, `p=0UFXp=1' will be parsed as `(p=0)U(F(X(p=1)))'.
*/
<not_prop>[a-zA-EH-QSTWYZ_][a-zA-EH-WYZ0-9_]* |
<not_prop>[a-zA-EH-QSTWYZ_][a-zA-EH-WYZ0-9_][a-zA-Z0-9_]* {
yylval->str = new std::string(yytext);
BEGIN(not_prop);
return ATOMIC_PROP;
}
/* Atomic propositions can also be enclosed in double quotes. */
\"[^\"]*\" {
yylval->str = new std::string(yytext + 1, yyleng - 2);
return ATOMIC_PROP;
}
\"[^\"]*\" {
yylval->str = new std::string(yytext + 1,
yyleng - 2);
BEGIN(not_prop);
return ATOMIC_PROP;
}
. return *yytext;
. return *yytext;
<<EOF>> return END_OF_INPUT;
<<EOF>> return END_OF_INPUT;
%{
/* Dummy use of yyunput to shut up a gcc warning. */