From f958bcdf1f9f66759a2512e4b7c0b0ba5647960a Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Sun, 28 Mar 2004 20:58:28 +0000 Subject: [PATCH] * 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'. --- src/libexpr/eval.cc | 1 + src/libexpr/parser.y | 2 ++ src/libexpr/primops.cc | 13 +++++++++++++ 3 files changed, 16 insertions(+) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index b4d76a137..2281ee721 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -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" || diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y index 44d1e06ab..b1fe9e093 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 '~' %% @@ -79,6 +80,7 @@ expr_op | expr_op OR expr_op { $$ = ATmake("OpOr(, )", $1, $3); } | expr_op IMPL expr_op { $$ = ATmake("OpImpl(, )", $1, $3); } | expr_op UPDATE expr_op { $$ = ATmake("OpUpdate(, )", $1, $3); } + | expr_op '~' expr_op { $$ = ATmake("SubPath(, )", $1, $3); } | expr_app ; diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 6c2bb33e4..5aefa5b41 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -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); @@ -128,6 +129,18 @@ 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); }