From ac4d39f9db28743b6c1e9def7a61241a50b02335 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Sun, 28 Mar 2004 21:15:01 +0000 Subject: [PATCH] * Added an operator `?' to test for attribute existence, e.g., `attrs ? x' yields true iff `attrs' has an attribute named `x'. --- src/libexpr/eval.cc | 9 ++++++++- src/libexpr/parser.y | 2 ++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 2281ee721..0623e4953 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -288,10 +288,17 @@ Expr evalExpr2(EvalState & state, Expr e) if (atMatch(m, e) >> "OpOr" >> e1 >> e2) return makeBool(evalBool(state, e1) || evalBool(state, e2)); - /* Attribut set update (//). */ + /* Attribute set update (//). */ if (atMatch(m, e) >> "OpUpdate" >> e1 >> e2) return updateAttrs(evalExpr(state, e1), evalExpr(state, e2)); + /* Attribute existence test (?). */ + if (atMatch(m, e) >> "OpHasAttr" >> e1 >> name) { + ATermMap attrs; + queryAllAttrs(evalExpr(state, e1), attrs); + return makeBool(attrs.get(name) != 0); + } + /* Barf. */ throw badTerm("invalid expression", e); } diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y index b1fe9e093..cfcbc589f 100644 --- a/src/libexpr/parser.y +++ b/src/libexpr/parser.y @@ -44,6 +44,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s) %nonassoc EQ NEQ %right UPDATE %left NEG +%nonassoc '?' %nonassoc '~' %% @@ -81,6 +82,7 @@ expr_op | expr_op IMPL expr_op { $$ = ATmake("OpImpl(, )", $1, $3); } | expr_op UPDATE expr_op { $$ = ATmake("OpUpdate(, )", $1, $3); } | expr_op '~' expr_op { $$ = ATmake("SubPath(, )", $1, $3); } + | expr_op '?' ID { $$ = ATmake("OpHasAttr(, )", $1, $3); } | expr_app ;