diff options
| author | Eelco Dolstra <e.dolstra@tudelft.nl> | 2004-02-04 16:49:51 +0000 |
|---|---|---|
| committer | Eelco Dolstra <e.dolstra@tudelft.nl> | 2004-02-04 16:49:51 +0000 |
| commit | 9d25466b34a5f7c1c8b1c273976cf59c33961a6c (patch) | |
| tree | ee4a5a60ae5de90fb301d75258ea627300065b2a /src/libexpr | |
| parent | 6d46e647ba16e19100dcd0abda9ca5a81ccf764f (diff) | |
* An attribute set update operator (//). E.g.,
{x=1; y=2; z=3;} // {y=4;} => {x=1; y=4; z=3;}
Diffstat (limited to 'src/libexpr')
| -rw-r--r-- | src/libexpr/eval.cc | 16 | ||||
| -rw-r--r-- | src/libexpr/lexer.l | 1 | ||||
| -rw-r--r-- | src/libexpr/parser.y | 2 |
3 files changed, 19 insertions, 0 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 802b83aa1..eaa4b4ea4 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -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) { e = evalExpr(state, e); @@ -264,6 +276,10 @@ Expr evalExpr2(EvalState & state, Expr e) if (atMatch(m, e) >> "OpOr" >> e1 >> 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. */ throw badTerm("invalid expression", e); } diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l index 853362cd0..ce1c4673d 100644 --- a/src/libexpr/lexer.l +++ b/src/libexpr/lexer.l @@ -57,6 +57,7 @@ inherit { return INHERIT; } \&\& { return AND; } \|\| { return OR; } \-\> { return IMPL; } +\/\/ { return UPDATE; } {ID} { yylval->t = ATmake("<str>", yytext); return ID; /* !!! alloc */ } {INT} { int n = atoi(yytext); /* !!! overflow */ diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y index d97106fca..6c0fdbda2 100644 --- a/src/libexpr/parser.y +++ b/src/libexpr/parser.y @@ -42,6 +42,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s) %left OR %left AND %nonassoc EQ NEQ +%right UPDATE %left NEG %% @@ -69,6 +70,7 @@ expr_op | expr_op AND expr_op { $$ = ATmake("OpAnd(<term>, <term>)", $1, $3); } | expr_op OR expr_op { $$ = ATmake("OpOr(<term>, <term>)", $1, $3); } | expr_op IMPL expr_op { $$ = ATmake("OpImpl(<term>, <term>)", $1, $3); } + | expr_op UPDATE expr_op { $$ = ATmake("OpUpdate(<term>, <term>)", $1, $3); } | expr_app ; |