From d7efd7639420f4c840cbfdfcbbb3c45292f3ac54 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Mon, 16 Oct 2006 15:55:34 +0000 Subject: * Big cleanup of the semantics of paths, strings, contexts, string concatenation and string coercion. This was a big mess (see e.g. NIX-67). Contexts are now folded into strings, so that they don't cause evaluation errors when they're not expected. The semantics of paths has been clarified (see nixexpr-ast.def). toString() and coerceToString() have been merged. Semantic change: paths are now copied to the store when they're in a concatenation (and in most other situations - that's the formalisation of the meaning of a path). So "foo " + ./bla evaluates to "foo /nix/store/hash...-bla", not "foo /path/to/current-dir/bla". This prevents accidental impurities, and is more consistent with the treatment of derivation outputs, e.g., `"foo " + bla' where `bla' is a derivation. (Here `bla' would be replaced by the output path of `bla'.) --- src/libexpr/nixexpr.hh | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'src/libexpr/nixexpr.hh') diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh index 674321f92400..2fdad73b78a3 100644 --- a/src/libexpr/nixexpr.hh +++ b/src/libexpr/nixexpr.hh @@ -71,6 +71,7 @@ struct TermFun }; ATerm bottomupRewrite(TermFun & f, ATerm e); + /* Query all attributes in an attribute set expression. The expression must be in normal form. */ void queryAllAttrs(Expr e, ATermMap & attrs, bool withPos = false); @@ -83,16 +84,28 @@ Expr queryAttr(Expr e, const string & name, ATerm & pos); /* Create an attribute set expression from an Attrs value. */ Expr makeAttrs(const ATermMap & attrs); + /* Perform a set of substitutions on an expression. */ Expr substitute(const Substitution & subs, Expr e); + /* Check whether all variables are defined in the given expression. Throw an exception if this isn't the case. */ void checkVarDefs(const ATermMap & def, Expr e); + /* Create an expression representing a boolean. */ Expr makeBool(bool b); + +/* Manipulation of Str() nodes. Note: matchStr() does not clear + context! */ +bool matchStr(Expr e, string & s, PathSet & context); + +Expr makeStr(const string & s, const PathSet & context = PathSet()); + + +/* Showing types, values. */ string showType(Expr e); string showValue(Expr e); -- cgit 1.4.1