* Okay, that's a bit harder than expected.

This commit is contained in:
Eelco Dolstra 2006-08-30 13:10:04 +00:00
parent dce1afdc67
commit f93f7b75be
3 changed files with 19 additions and 9 deletions

View file

@ -466,11 +466,15 @@ Expr evalExpr2(EvalState & state, Expr e)
}
}
/* Generic equality. */
/* Generic equality/inequality. Note that the behaviour on
composite data (lists, attribute sets) and functions is
undefined, since the subterms of those terms are not evaluated.
However, we don't want to make (==) strict, because that would
make operations like `big_derivation == null' very slow (unless
we were to evaluate them side-by-side). */
if (matchOpEq(e, e1, e2))
return makeBool(evalExpr(state, e1) == evalExpr(state, e2));
/* Generic inequality. */
if (matchOpNEq(e, e1, e2))
return makeBool(evalExpr(state, e1) != evalExpr(state, e2));
@ -594,7 +598,7 @@ Expr evalFile(EvalState & state, const Path & path)
}
Expr strictEvalExpr(EvalState & state, Expr e)
Expr strictEvalExpr(EvalState & state, Expr e, bool canonicalise)
{
e = evalExpr(state, e);
@ -604,8 +608,10 @@ Expr strictEvalExpr(EvalState & state, Expr e)
for (ATermIterator i(as); i; ++i) {
ATerm name; Expr e; ATerm pos;
if (!matchBind(*i, name, e, pos)) abort(); /* can't happen */
as2 = ATinsert(as2, makeBind(name, strictEvalExpr(state, e), pos));
as2 = ATinsert(as2, makeBind(name, strictEvalExpr(state, e, canonicalise),
canonicalise ? makeNoPos() : pos));
}
/* !!! sort attributes if canonicalise == true */
return makeAttrs(ATreverse(as2));
}
@ -613,7 +619,7 @@ Expr strictEvalExpr(EvalState & state, Expr e)
if (matchList(e, es)) {
ATermList es2 = ATempty;
for (ATermIterator i(es); i; ++i)
es2 = ATinsert(es2, strictEvalExpr(state, *i));
es2 = ATinsert(es2, strictEvalExpr(state, *i, canonicalise));
return makeList(ATreverse(es2));
}
@ -630,13 +636,14 @@ Expr strictEvalExpr(EvalState & state, Expr e)
if (matchValidValues(valids, valids2)) {
ATermList valids3 = ATempty;
for (ATermIterator j(valids2); j; ++j)
valids3 = ATinsert(valids3, strictEvalExpr(state, *j));
valids3 = ATinsert(valids3, strictEvalExpr(state, *j, canonicalise));
valids = makeValidValues(ATreverse(valids3));
}
formals2 = ATinsert(formals2, makeFormal(name, valids, dummy));
}
return makeFunction(ATreverse(formals2), body, pos);
return makeFunction(ATreverse(formals2), body,
canonicalise ? makeNoPos() : pos);
}
return e;

View file

@ -48,8 +48,11 @@ Expr evalExpr(EvalState & state, Expr e);
Expr evalFile(EvalState & state, const Path & path);
/* Evaluate an expression, and recursively evaluate list elements and
attributes. */
Expr strictEvalExpr(EvalState & state, Expr e);
attributes. If `canonicalise' is true, we remove things like
position information and make sure that attribute sets are in
sorded order. */
Expr strictEvalExpr(EvalState & state, Expr e,
bool canonicalise = false);
/* Specific results. */
string evalString(EvalState & state, Expr e);