nix-super/src/libutil/aterm.hh
2003-11-25 12:05:48 +00:00

86 lines
1.7 KiB
C++

#ifndef __ATERM_H
#define __ATERM_H
extern "C" {
#include <aterm2.h>
}
#include "util.hh"
/* Print an ATerm. */
string atPrint(ATerm t);
/* Write an ATerm to an output stream. */
ostream & operator << (ostream & stream, ATerm e);
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;
}
};
/* Type-safe matching. */
struct ATMatcher
{
ATerm t;
int pos;
const static int failPos = -2;
const static int funPos = -1;
ATMatcher() : t(0), pos(failPos)
{
}
operator bool() const
{
return pos != failPos;
}
};
/* Initiate matching of a term. */
ATMatcher & atMatch(ATMatcher & pos, ATerm t);
/* Get the next argument of an application. */
ATMatcher & operator >> (ATMatcher & pos, ATerm & out);
/* Get the name of the function symbol of an application, or the next
argument of an application as a string. */
ATMatcher & operator >> (ATMatcher & pos, string & out);
/* Like the previous, but check that the string is equal to the given
string. */
ATMatcher & operator >> (ATMatcher & pos, const string & s);
/* Get the next argument of an application, and verify that it is a
integer. */
ATMatcher & operator >> (ATMatcher & pos, int & n);
/* Get the next argument of an application, and verify that it is a
list. */
ATMatcher & operator >> (ATMatcher & pos, ATermList & out);
/* Throw an exception with an error message containing the given
aterm. */
Error badTerm(const format & f, ATerm t);
#endif /* !__ATERM_H */