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* `nix-instantiate --print-args': print out the valid values for 

functions arguments that have a domain.
This commit is contained in:
Eelco Dolstra 2006-07-28 14:01:29 +00:00
parent ca2238cf81
commit c11839d7b2
3 changed files with 37 additions and 3 deletions
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24
src/libexpr/nixexpr.cc
View File

@ -308,3 +308,27 @@ string showType(Expr e)
return "an unknown type";
}
string showValue(Expr e)
{
ATerm s;
int i;
if (matchStr(e, s)) {
string t = aterm2String(s), u;
for (string::iterator i = t.begin(); i != t.end(); ++i)
if (*i == '\"' || *i == '\\') u += "\\" + *i;
else if (*i == '\n') u += "\\n";
else if (*i == '\r') u += "\\r";
else if (*i == '\t') u += "\\t";
else u += *i;
return "\"" + u + "\"";
}
if (matchPath(e, s)) return aterm2String(s);
if (matchUri(e, s)) return aterm2String(s);
if (matchNull(e)) return "null";
if (matchInt(e, i)) return (format("%1%") % i).str();
if (e == eTrue) return "true";
if (e == eFalse) return "false";
/* !!! incomplete */
return "<unknown>";
}

2
src/libexpr/nixexpr.hh
View File

@ -92,5 +92,7 @@ Expr makeBool(bool b);
string showType(Expr e);
string showValue(Expr e);
#endif /* !__NIXEXPR_H */

14
src/nix-instantiate/main.cc
View File

@ -44,9 +44,17 @@ static void printResult(EvalState & state, Expr e,
ATerm body, pos;
if (matchFunction(e, formals, body, pos)) {
for (ATermIterator i(formals); i; ++i) {
Expr name; ATerm d1, d2;
if (!matchFormal(*i, name, d1, d2)) abort();
cout << format("%1%\n") % aterm2String(name);
Expr name; ValidValues valids; ATerm dummy;
if (!matchFormal(*i, name, valids, dummy)) abort();
cout << format("%1%: ") % aterm2String(name);
ATermList valids2;
if (matchValidValues(valids, valids2)) {
for (ATermIterator j(valids2); j; ++j) {
Expr e = evalExpr(state, *j);
cout << format("%1% ") % showValue(e);
}
}
cout << format("\n");
}
} else
printMsg(lvlError, "warning: expression does not evaluate to a function");