* An attribute set update operator (//). E.g.,

{x=1; y=2; z=3;} // {y=4;}  =>  {x=1; y=4; z=3;}
This commit is contained in:
Eelco Dolstra 2004-02-04 16:49:51 +00:00
parent 6d46e647ba
commit 9d25466b34
3 changed files with 19 additions and 0 deletions

View file

@ -134,6 +134,18 @@ ATerm expandRec(ATerm e, ATermList rbnds, ATermList nrbnds)
} }
static Expr updateAttrs(Expr e1, Expr e2)
{
/* Note: e1 and e2 should be in normal form. */
ATermMap attrs;
queryAllAttrs(e1, attrs);
queryAllAttrs(e2, attrs);
return makeAttrs(attrs);
}
string evalString(EvalState & state, Expr e) string evalString(EvalState & state, Expr e)
{ {
e = evalExpr(state, e); e = evalExpr(state, e);
@ -264,6 +276,10 @@ Expr evalExpr2(EvalState & state, Expr e)
if (atMatch(m, e) >> "OpOr" >> e1 >> e2) if (atMatch(m, e) >> "OpOr" >> e1 >> e2)
return makeBool(evalBool(state, e1) || evalBool(state, e2)); return makeBool(evalBool(state, e1) || evalBool(state, e2));
/* Attribut set update (//). */
if (atMatch(m, e) >> "OpUpdate" >> e1 >> e2)
return updateAttrs(evalExpr(state, e1), evalExpr(state, e2));
/* Barf. */ /* Barf. */
throw badTerm("invalid expression", e); throw badTerm("invalid expression", e);
} }

View file

@ -57,6 +57,7 @@ inherit { return INHERIT; }
\&\& { return AND; } \&\& { return AND; }
\|\| { return OR; } \|\| { return OR; }
\-\> { return IMPL; } \-\> { return IMPL; }
\/\/ { return UPDATE; }
{ID} { yylval->t = ATmake("<str>", yytext); return ID; /* !!! alloc */ } {ID} { yylval->t = ATmake("<str>", yytext); return ID; /* !!! alloc */ }
{INT} { int n = atoi(yytext); /* !!! overflow */ {INT} { int n = atoi(yytext); /* !!! overflow */

View file

@ -42,6 +42,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s)
%left OR %left OR
%left AND %left AND
%nonassoc EQ NEQ %nonassoc EQ NEQ
%right UPDATE
%left NEG %left NEG
%% %%
@ -69,6 +70,7 @@ expr_op
| expr_op AND expr_op { $$ = ATmake("OpAnd(<term>, <term>)", $1, $3); } | expr_op AND expr_op { $$ = ATmake("OpAnd(<term>, <term>)", $1, $3); }
| expr_op OR expr_op { $$ = ATmake("OpOr(<term>, <term>)", $1, $3); } | expr_op OR expr_op { $$ = ATmake("OpOr(<term>, <term>)", $1, $3); }
| expr_op IMPL expr_op { $$ = ATmake("OpImpl(<term>, <term>)", $1, $3); } | expr_op IMPL expr_op { $$ = ATmake("OpImpl(<term>, <term>)", $1, $3); }
| expr_op UPDATE expr_op { $$ = ATmake("OpUpdate(<term>, <term>)", $1, $3); }
| expr_app | expr_app
; ;