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-rw-r--r--src/libexpr/eval.cc500
1 files changed, 8 insertions, 492 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index e72538e60874..2d22a4fdc5c4 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -27,7 +27,14 @@ std::ostream & operator << (std::ostream & str, Value & v)
         str << (v.boolean ? "true" : "false");
         break;
     case tString:
-        str << "\"" << v.string.s << "\""; // !!! escaping
+        str << "\"";
+        for (const char * i = v.string.s; *i; i++)
+            if (*i == '\"' || *i == '\\') str << "\\" << *i;
+            else if (*i == '\n') str << "\\n";
+            else if (*i == '\r') str << "\\r";
+            else if (*i == '\t') str << "\\t";
+            else str << *i;
+        str << "\"";
         break;
     case tPath:
         str << v.path; // !!! escaping?
@@ -930,497 +937,6 @@ bool EvalState::eqValues(Value & v1, Value & v2)
 }
 
 
-#if 0
-/* Pattern-match `pat' against `arg'.  The result is a set of
-   substitutions (`subs') and a set of recursive substitutions
-   (`subsRecursive').  The latter can refer to the variables bound by
-   both `subs' and `subsRecursive'. */
-static void patternMatch(EvalState & state,
-    Pattern pat, Expr arg, ATermMap & subs, ATermMap & subsRecursive)
-{
-    ATerm name;
-    ATermList formals;
-    ATermBool ellipsis;
-    
-    if (matchVarPat(pat, name)) 
-        subs.set(name, arg);
-
-    else if (matchAttrsPat(pat, formals, ellipsis, name)) {
-
-        arg = evalExpr(state, arg);
-
-        if (name != sNoAlias) subs.set(name, arg);
-
-        /* Get the actual arguments. */
-        ATermMap attrs;
-        queryAllAttrs(arg, attrs);
-        unsigned int nrAttrs = attrs.size();
-
-        /* For each formal argument, get the actual argument.  If
-           there is no matching actual argument but the formal
-           argument has a default, use the default. */
-        unsigned int attrsUsed = 0;
-        for (ATermIterator i(formals); i; ++i) {
-            Expr name, def;
-            DefaultValue def2;
-            if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
-
-            Expr value = attrs[name];
-
-            if (value == 0) {
-                if (!matchDefaultValue(def2, def)) def = 0;
-                if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
-                    % aterm2String(name));
-                subsRecursive.set(name, def);
-            } else {
-                attrsUsed++;
-                attrs.remove(name);
-                subs.set(name, value);
-            }
-
-        }
-
-        /* Check that each actual argument is listed as a formal
-           argument (unless the attribute match specifies a `...'). */
-        if (ellipsis == eFalse && attrsUsed != nrAttrs)
-            throw TypeError(format("the function does not expect an argument named `%1%'")
-                % aterm2String(attrs.begin()->key));
-    }
-
-    else abort();
-}
-
-
-/* Substitute an argument set into the body of a function. */
-static Expr substArgs(EvalState & state,
-    Expr body, Pattern pat, Expr arg)
-{
-    ATermMap subs(16), subsRecursive(16);
-    
-    patternMatch(state, pat, arg, subs, subsRecursive);
-
-    /* If we used any default values, make a recursive attribute set
-       out of the (argument-name, value) tuples.  This is so that we
-       can support default values that refer to each other, e.g.  ({x,
-       y ? x + x}: y) {x = "foo";} evaluates to "foofoo". */
-    if (subsRecursive.size() != 0) {
-        ATermList recAttrs = ATempty;
-        foreach (ATermMap::const_iterator, i, subs)
-            recAttrs = ATinsert(recAttrs, makeBind(i->key, i->value, makeNoPos()));
-        foreach (ATermMap::const_iterator, i, subsRecursive)
-            recAttrs = ATinsert(recAttrs, makeBind(i->key, i->value, makeNoPos()));
-        Expr rec = makeRec(recAttrs, ATempty);
-        foreach (ATermMap::const_iterator, i, subsRecursive)
-            subs.set(i->key, makeSelect(rec, i->key));
-    }
-
-    return substitute(Substitution(0, &subs), body);
-}
-
-
-/* Transform a mutually recursive set into a non-recursive set.  Each
-   attribute is transformed into an expression that has all references
-   to attributes substituted with selection expressions on the
-   original set.  E.g., e = `rec {x = f x y; y = x;}' becomes `{x = f
-   (e.x) (e.y); y = e.x;}'. */
-LocalNoInline(ATerm expandRec(EvalState & state, ATerm e, ATermList rbnds, ATermList nrbnds))
-{
-    ATerm name;
-    Expr e2;
-    Pos pos;
-    Expr eOverrides = 0;
-
-    /* Create the substitution list. */
-    ATermMap subs(ATgetLength(rbnds) + ATgetLength(nrbnds));
-    for (ATermIterator i(rbnds); i; ++i) {
-        if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
-        subs.set(name, makeSelect(e, name));
-    }
-    for (ATermIterator i(nrbnds); i; ++i) {
-        if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
-        if (name == sOverrides) eOverrides = e2;
-        subs.set(name, e2);
-    }
-
-    /* If the rec contains an attribute called `__overrides', then
-       evaluate it, and add the attributes in that set to the rec.
-       This allows overriding of recursive attributes, which is
-       otherwise not possible.  (You can use the // operator to
-       replace an attribute, but other attributes in the rec will
-       still reference the original value, because that value has been
-       substituted into the bodies of the other attributes.  Hence we
-       need __overrides.) */
-    ATermMap overrides;
-    if (eOverrides) {
-        eOverrides = evalExpr(state, eOverrides);
-        queryAllAttrs(eOverrides, overrides, false);
-        foreach (ATermMap::const_iterator, i, overrides)
-            subs.set(i->key, i->value);
-    }
-
-    Substitution subs_(0, &subs);
-
-    /* Create the non-recursive set. */
-    ATermMap as(ATgetLength(rbnds) + ATgetLength(nrbnds));
-    for (ATermIterator i(rbnds); i; ++i) {
-        if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
-        as.set(name, makeAttrRHS(substitute(subs_, e2), pos));
-    }
-
-    if (eOverrides)
-        foreach (ATermMap::const_iterator, i, overrides)
-            as.set(i->key, makeAttrRHS(i->value, makeNoPos()));
-
-    /* Copy the non-recursive bindings.  !!! inefficient */
-    for (ATermIterator i(nrbnds); i; ++i) {
-        if (!matchBind(*i, name, e2, pos)) abort(); /* can't happen */
-        as.set(name, makeAttrRHS(e2, pos));
-    }
-
-    return makeAttrs(as);
-}
-
-
-static void flattenList(EvalState & state, Expr e, ATermList & result)
-{
-    ATermList es;
-    e = evalExpr(state, e);
-    if (matchList(e, es))
-        for (ATermIterator i(es); i; ++i)
-            flattenList(state, *i, result);
-    else
-        result = ATinsert(result, e);
-}
-
-
-ATermList flattenList(EvalState & state, Expr e)
-{
-    ATermList result = ATempty;
-    flattenList(state, e, result);
-    return ATreverse(result);
-}
-
-
-/* Evaluation of various language constructs.  These have been taken
-   out of evalExpr2 to reduce stack space usage.  (GCC is really dumb
-   about stack space: it just adds up all the local variables and
-   temporaries of every scope into one huge stack frame.  This is
-   really bad for deeply recursive functions.) */
-
-
-LocalNoInline(Expr evalVar(EvalState & state, ATerm name))
-{
-    ATerm primOp = state.primOps.get(name);
-    if (!primOp)
-        throw EvalError(format("impossible: undefined variable `%1%'") % aterm2String(name));
-    int arity;
-    ATermBlob fun;
-    if (!matchPrimOpDef(primOp, arity, fun)) abort();
-    if (arity == 0)
-        /* !!! backtrace for primop call */
-        return ((PrimOp) ATgetBlobData(fun)) (state, ATermVector());
-    else
-        return makePrimOp(arity, fun, ATempty);
-}
-
-
-LocalNoInline(Expr evalCall(EvalState & state, Expr fun, Expr arg))
-{
-    Pattern pat;
-    ATerm pos;
-    Expr body;
-        
-    /* Evaluate the left-hand side. */
-    fun = evalExpr(state, fun);
-
-    /* Is it a primop or a function? */
-    int arity;
-    ATermBlob funBlob;
-    ATermList args;
-    if (matchPrimOp(fun, arity, funBlob, args)) {
-        args = ATinsert(args, arg);
-        if (ATgetLength(args) == arity) {
-            /* Put the arguments in a vector in reverse (i.e.,
-               actual) order. */
-            ATermVector args2(arity);
-            for (ATermIterator i(args); i; ++i)
-                args2[--arity] = *i;
-            /* !!! backtrace for primop call */
-            return ((PrimOp) ATgetBlobData(funBlob))
-                (state, args2);
-        } else
-            /* Need more arguments, so propagate the primop. */
-            return makePrimOp(arity, funBlob, args);
-    }
-
-    else if (matchFunction(fun, pat, body, pos)) {
-        try {
-            return evalExpr(state, substArgs(state, body, pat, arg));
-        } catch (Error & e) {
-            addErrorPrefix(e, "while evaluating the function at %1%:\n",
-                showPos(pos));
-            throw;
-        }
-    }
-        
-    else throwTypeError(
-        "attempt to call something which is neither a function nor a primop (built-in operation) but %1%",
-        showType(fun));
-}
-
-
-LocalNoInline(Expr evalWith(EvalState & state, Expr defs, Expr body, ATerm pos))
-{
-    ATermMap attrs;
-    try {
-        defs = evalExpr(state, defs);
-        queryAllAttrs(defs, attrs);
-    } catch (Error & e) {
-        addErrorPrefix(e, "while evaluating the `with' definitions at %1%:\n",
-            showPos(pos));
-        throw;
-    }
-    try {
-        body = substitute(Substitution(0, &attrs), body);
-        checkVarDefs(state.primOps, body);
-        return evalExpr(state, body);
-    } catch (Error & e) {
-        addErrorPrefix(e, "while evaluating the `with' body at %1%:\n",
-            showPos(pos));
-        throw;
-    } 
-}
-
-
-/* Implementation of the `==' and `!=' operators. */
-LocalNoInline(bool areEqual(EvalState & state, Expr e1, Expr e2))
-{
-    e1 = evalExpr(state, e1);
-    e2 = evalExpr(state, e2);
-
-    /* We cannot test functions/primops for equality, and we currently
-       don't support testing equality between attribute sets or lists
-       - that would have to be a deep equality test to be sound. */
-    AFun sym1 = ATgetAFun(e1);
-    AFun sym2 = ATgetAFun(e2);
-
-    if (sym1 != sym2) return false;
-
-    /* Functions are incomparable. */
-    if (sym1 == symFunction || sym1 == symPrimOp) return false;
-
-    if (!state.allowUnsafeEquality && sym1 == symAttrs)
-        throw EvalError("comparison of attribute sets is not implemented");
-
-    /* !!! This allows comparisons of infinite data structures to
-       succeed, such as `let x = [x]; in x == x'.  This is
-       undesirable, since equivalent (?) terms such as `let x = [x]; y
-       = [y]; in x == y' don't terminate. */
-    if (e1 == e2) return true;
-    
-    if (sym1 == symList) {
-        ATermList es1; matchList(e1, es1);
-        ATermList es2; matchList(e2, es2);
-        if (ATgetLength(es1) != ATgetLength(es2)) return false;
-        ATermIterator i(es1), j(es2);
-        while (*i) {
-            if (!areEqual(state, *i, *j)) return false;
-            ++i; ++j;
-        }
-        return true;
-    }
-    
-    return false;
-}
-
-
-Expr evalExpr2(EvalState & state, Expr e)
-{
-    /* When changing this function, make sure that you don't cause a
-       (large) increase in stack consumption! */
-    
-    char x;
-    if (&x < deepestStack) deepestStack = &x;
-    
-    Expr e1, e2, e3;
-    ATerm name, pos;
-    AFun sym = ATgetAFun(e);
-
-    /* Normal forms. */
-    if (sym == symStr ||
-        sym == symPath ||
-        sym == symNull ||
-        sym == symInt ||
-        sym == symBool ||
-        sym == symFunction ||
-        sym == symAttrs ||
-        sym == symList ||
-        sym == symPrimOp)
-        return e;
-    
-    /* The `Closed' constructor is just a way to prevent substitutions
-       into expressions not containing free variables. */
-    if (matchClosed(e, e1))
-        return evalExpr(state, e1);
-
-    /* Any encountered variables must be primops (since undefined
-       variables are detected after parsing). */
-    if (matchVar(e, name)) return evalVar(state, name);
-
-    /* Function application. */
-    if (matchCall(e, e1, e2)) return evalCall(state, e1, e2);
-
-    /* Attribute selection. */
-    if (matchSelect(e, e1, name)) return evalSelect(state, e1, name);
-
-    /* Mutually recursive sets. */
-    ATermList rbnds, nrbnds;
-    if (matchRec(e, rbnds, nrbnds))
-        return expandRec(state, e, rbnds, nrbnds);
-
-    /* Conditionals. */
-    if (matchIf(e, e1, e2, e3))
-        return evalExpr(state, evalBool(state, e1) ? e2 : e3);
-
-    /* Assertions. */
-    if (matchAssert(e, e1, e2, pos)) return evalAssert(state, e1, e2, pos);
-
-    /* Withs. */
-    if (matchWith(e, e1, e2, pos)) return evalWith(state, e1, e2, pos);
-
-    /* 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(areEqual(state, e1, e2));
-        
-    if (matchOpNEq(e, e1, e2)) return makeBool(!areEqual(state, e1, e2));
-        
-    /* Negation. */
-    if (matchOpNot(e, e1))
-        return makeBool(!evalBool(state, e1));
-
-    /* Implication. */
-    if (matchOpImpl(e, e1, e2))
-        return makeBool(!evalBool(state, e1) || evalBool(state, e2));
-
-    /* Conjunction (logical AND). */
-    if (matchOpAnd(e, e1, e2))
-        return makeBool(evalBool(state, e1) && evalBool(state, e2));
-
-    /* Disjunction (logical OR). */
-    if (matchOpOr(e, e1, e2))
-        return makeBool(evalBool(state, e1) || evalBool(state, e2));
-
-    /* Attribute set update (//). */
-    if (matchOpUpdate(e, e1, e2))
-        return updateAttrs(evalExpr(state, e1), evalExpr(state, e2));
-
-    /* Attribute existence test (?). */
-    if (matchOpHasAttr(e, e1, name)) return evalHasAttr(state, e1, name);
-
-    /* String or path concatenation. */
-    if (sym == symOpPlus || sym == symConcatStrings)
-        return evalPlusConcat(state, e);
-
-    /* Backwards compatability: subpath operator (~). */
-    if (matchSubPath(e, e1, e2)) return evalSubPath(state, e1, e2);
-
-    /* List concatenation. */
-    if (matchOpConcat(e, e1, e2)) return evalOpConcat(state, e1, e2);
-
-    /* Barf. */
-    abort();
-}
-
-
-Expr evalExpr(EvalState & state, Expr e)
-{
-    checkInterrupt();
-
-#if 0
-    startNest(nest, lvlVomit,
-        format("evaluating expression: %1%") % e);
-#endif
-
-    state.nrEvaluated++;
-
-    /* Consult the memo table to quickly get the normal form of
-       previously evaluated expressions. */
-    Expr nf = state.normalForms.get(e);
-    if (nf) {
-        if (nf == makeBlackHole())
-            throwEvalError("infinite recursion encountered");
-        state.nrCached++;
-        return nf;
-    }
-
-    /* Otherwise, evaluate and memoize. */
-    state.normalForms.set(e, makeBlackHole());
-    try {
-        nf = evalExpr2(state, e);
-    } catch (Error & err) {
-        state.normalForms.remove(e);
-        throw;
-    }
-    state.normalForms.set(e, nf);
-    return nf;
-}
-
-
-static Expr strictEvalExpr(EvalState & state, Expr e, ATermMap & nfs);
-
-
-static Expr strictEvalExpr_(EvalState & state, Expr e, ATermMap & nfs)
-{
-    e = evalExpr(state, e);
-
-    ATermList as;
-    if (matchAttrs(e, as)) {
-        ATermList as2 = ATempty;
-        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, nfs), pos));
-        }
-        return makeAttrs(ATreverse(as2));
-    }
-    
-    ATermList es;
-    if (matchList(e, es)) {
-        ATermList es2 = ATempty;
-        for (ATermIterator i(es); i; ++i)
-            es2 = ATinsert(es2, strictEvalExpr(state, *i, nfs));
-        return makeList(ATreverse(es2));
-    }
-    
-    return e;
-}
-
-
-static Expr strictEvalExpr(EvalState & state, Expr e, ATermMap & nfs)
-{
-    Expr nf = nfs.get(e);
-    if (nf) return nf;
-
-    nf = strictEvalExpr_(state, e, nfs);
-
-    nfs.set(e, nf);
-    
-    return nf;
-}
-
-
-Expr strictEvalExpr(EvalState & state, Expr e)
-{
-    ATermMap strictNormalForms;
-    return strictEvalExpr(state, e, strictNormalForms);
-}
-#endif
-
-
 void EvalState::printStats()
 {
     char x;