tvl-depot/src/libutil/aterm.hh
Eelco Dolstra d7efd76394 * 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'.)
2006-10-16 15:55:34 +00:00

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C++

#ifndef __ATERM_H
#define __ATERM_H
#include <aterm2.h>
#include "types.hh"
namespace nix {
/* Print an ATerm. */
string atPrint(ATerm t);
class ATermIterator
{
ATermList t;
public:
ATermIterator(ATermList _t) : t(_t) { }
ATermIterator & operator ++ ()
{
t = ATgetNext(t);
return *this;
}
ATerm operator * ()
{
return ATgetFirst(t);
}
operator bool ()
{
return t != ATempty;
}
};
/* Throw an exception with an error message containing the given
aterm. */
Error badTerm(const format & f, ATerm t);
/* Convert strings to ATerms. */
ATerm toATerm(const char * s);
ATerm toATerm(const string & s);
ATermList toATermList(const StringSet & ss);
}
/* Write an ATerm to an output stream. */
std::ostream & operator << (std::ostream & stream, ATerm e);
#endif /* !__ATERM_H */