* Added an operator `~' to select paths within a derivation. E.g.,

{stdenv, bash}: derivation {
      builder = bash ~ /bin/sh;
      args = ["-e" "-x" ./builder.sh];
      ...
    }

  Here the attribute `builder' will evaluate to, e.g.,
  `/nix/store/1234abcd...-bash-2.0.1/bin/sh'.
This commit is contained in:
Eelco Dolstra 2004-03-28 20:58:28 +00:00
parent db3e644c1c
commit f958bcdf1f
3 changed files with 16 additions and 0 deletions

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@ -190,6 +190,7 @@ Expr evalExpr2(EvalState & state, Expr e)
if (atMatch(m, e) >> cons &&
(cons == "Str" ||
cons == "Path" ||
cons == "SubPath" ||
cons == "Uri" ||
cons == "Null" ||
cons == "Int" ||

View File

@ -44,6 +44,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s)
%nonassoc EQ NEQ
%right UPDATE
%left NEG
%nonassoc '~'
%%
@ -79,6 +80,7 @@ expr_op
| 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 { $$ = ATmake("OpUpdate(<term>, <term>)", $1, $3); }
| expr_op '~' expr_op { $$ = ATmake("SubPath(<term>, <term>)", $1, $3); }
| expr_app
;

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@ -85,6 +85,7 @@ static void processBinding(EvalState & state, Expr e, StoreExpr & ne,
string s;
ATermList es;
int n;
Expr e1, e2;
if (atMatch(m, e) >> "Str" >> s) ss.push_back(s);
else if (atMatch(m, e) >> "Uri" >> s) ss.push_back(s);
@ -129,6 +130,18 @@ static void processBinding(EvalState & state, Expr e, StoreExpr & ne,
else if (atMatch(m, e) >> "Null") ss.push_back("");
else if (atMatch(m, e) >> "SubPath" >> e1 >> e2) {
Strings ss2;
processBinding(state, evalExpr(state, e1), ne, ss2);
if (ss2.size() != 1)
throw Error("left-hand side of `~' operator cannot be a list");
e2 = evalExpr(state, e2);
if (!(atMatch(m, e2) >> "Str" >> s ||
(atMatch(m, e2) >> "Path" >> s)))
throw Error("right-hand side of `~' operator must be a path or string");
ss.push_back(canonPath(ss2.front() + "/" + s));
}
else throw badTerm("invalid derivation binding", e);
}