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

118 lines
2.4 KiB
C++

#include "aterm.hh"
string atPrint(ATerm t)
{
if (!t) throw Error("attempt to print null aterm");
char * s = ATwriteToString(t);
if (!s) throw Error("cannot print term");
return s;
}
ostream & operator << (ostream & stream, ATerm e)
{
return stream << atPrint(e);
}
ATMatcher & atMatch(ATMatcher & pos, ATerm t)
{
pos.t = t;
pos.pos = ATMatcher::funPos;
return pos;
}
static inline bool failed(const ATMatcher & pos)
{
return pos.pos == ATMatcher::failPos;
}
static inline ATMatcher & fail(ATMatcher & pos)
{
pos.pos = ATMatcher::failPos;
return pos;
}
ATMatcher & operator >> (ATMatcher & pos, ATerm & out)
{
out = 0;
if (failed(pos)) return pos;
if (pos.pos == ATMatcher::funPos ||
ATgetType(pos.t) != AT_APPL ||
pos.pos >= (int) ATgetArity(ATgetAFun(pos.t)))
return fail(pos);
out = ATgetArgument(pos.t, pos.pos);
pos.pos++;
return pos;
}
ATMatcher & operator >> (ATMatcher & pos, string & out)
{
out = "";
if (pos.pos == ATMatcher::funPos) {
if (ATgetType(pos.t) != AT_APPL) return fail(pos);
out = ATgetName(ATgetAFun(pos.t));
pos.pos = 0;
} else {
ATerm t;
pos = pos >> t;
if (failed(pos)) return pos;
if (ATgetType(t) != AT_APPL ||
ATgetArity(ATgetAFun(t)) != 0)
return fail(pos);
out = ATgetName(ATgetAFun(t));
}
return pos;
}
ATMatcher & operator >> (ATMatcher & pos, const string & s)
{
string s2;
pos = pos >> s2;
if (failed(pos)) return pos;
if (s != s2) return fail(pos);
return pos;
}
ATMatcher & operator >> (ATMatcher & pos, int & n)
{
n = 0;
ATerm t;
pos = pos >> t;
if (failed(pos)) return pos;
if (ATgetType(t) != AT_INT) return fail(pos);
n = ATgetInt((ATermInt) t);
return pos;
}
ATMatcher & operator >> (ATMatcher & pos, ATermList & out)
{
out = 0;
ATerm t;
pos = pos >> t;
if (failed(pos)) return pos;
if (ATgetType(t) != AT_LIST) return fail(pos);
out = (ATermList) t;
return pos;
}
Error badTerm(const format & f, ATerm t)
{
char * s = ATwriteToString(t);
if (!s) throw Error("cannot print term");
if (strlen(s) > 1000) {
int len;
s = ATwriteToSharedString(t, &len);
if (!s) throw Error("cannot print term");
}
return Error(format("%1%, in `%2%'") % f.str() % (string) s);
}