* Implemented `map'.
This commit is contained in:
Eelco Dolstra
parent
d78a05ab40
commit
5b72d8a749
4 changed files with 139 additions and 108 deletions
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@ -68,6 +68,8 @@ void run(Strings args)
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doTest("let x = x; in if true || x then 1 else 2");
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doTest("/etc/passwd");
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doTest("import ./foo.nix");
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doTest("map (x: __add 1 x) [ 1 2 3 ]");
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doTest("map (__add 1) [ 1 2 3 ]");
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}
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@ -328,106 +328,9 @@ void EvalState::eval(Env & env, Expr e, Value & v)
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Expr fun, arg;
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if (matchCall(e, fun, arg)) {
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eval(env, fun, v);
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if (v.type == tPrimOp || v.type == tPrimOpApp) {
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unsigned int argsLeft =
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v.type == tPrimOp ? v.primOp.arity : v.primOpApp.argsLeft;
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if (argsLeft == 1) {
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/* We have all the arguments, so call the primop.
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First find the primop. */
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Value * primOp = &v;
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while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
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assert(primOp->type == tPrimOp);
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unsigned int arity = primOp->primOp.arity;
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Value vLastArg;
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mkThunk(vLastArg, env, arg);
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/* Put all the arguments in an array. */
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Value * vArgs[arity];
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unsigned int n = arity - 1;
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vArgs[n--] = &vLastArg;
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for (Value * arg = &v; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
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vArgs[n--] = arg->primOpApp.right;
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/* And call the primop. */
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primOp->primOp.fun(*this, vArgs, v);
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} else {
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Value * v2 = allocValues(2);
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v2[0] = v;
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mkThunk(v2[1], env, arg);
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v.type = tPrimOpApp;
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v.primOpApp.left = &v2[0];
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v.primOpApp.right = &v2[1];
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v.primOpApp.argsLeft = argsLeft - 1;
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}
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return;
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}
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if (v.type != tLambda) throw TypeError("expected function");
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Env & env2(allocEnv());
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env2.up = &env;
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ATermList formals; ATerm ellipsis;
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if (matchVarPat(v.lambda.pat, name)) {
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Value & vArg = env2.bindings[name];
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nrValues++;
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mkThunk(vArg, env, arg);
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}
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else if (matchAttrsPat(v.lambda.pat, formals, ellipsis, name)) {
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Value * vArg;
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Value vArg_;
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if (name == sNoAlias)
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vArg = &vArg_;
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else {
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vArg = &env2.bindings[name];
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nrValues++;
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}
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eval(env, arg, *vArg);
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forceAttrs(*vArg);
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/* For each formal argument, get the actual argument. If
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there is no matching actual argument but the formal
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argument has a default, use the default. */
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unsigned int attrsUsed = 0;
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for (ATermIterator i(formals); i; ++i) {
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Expr def; Sym name;
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DefaultValue def2;
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if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
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Bindings::iterator j = vArg->attrs->find(name);
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Value & v = env2.bindings[name];
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nrValues++;
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if (j == vArg->attrs->end()) {
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if (!matchDefaultValue(def2, def)) def = 0;
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if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
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% aterm2String(name));
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mkThunk(v, env2, def);
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} else {
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attrsUsed++;
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v.type = tCopy;
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v.val = &j->second;
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}
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}
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/* Check that each actual argument is listed as a formal
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argument (unless the attribute match specifies a
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`...'). TODO: show the names of the
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expected/unexpected arguments. */
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if (ellipsis == eFalse && attrsUsed != vArg->attrs->size())
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throw TypeError("function called with unexpected argument");
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}
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else abort();
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eval(env2, v.lambda.body, v);
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Value vArg;
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mkThunk(vArg, env, arg); // !!! should this be on the heap?
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callFunction(v, vArg, v);
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return;
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}
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@ -519,6 +422,103 @@ void EvalState::eval(Env & env, Expr e, Value & v)
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}
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void EvalState::callFunction(Value & fun, Value & arg, Value & v)
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{
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if (fun.type == tPrimOp || fun.type == tPrimOpApp) {
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unsigned int argsLeft =
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fun.type == tPrimOp ? fun.primOp.arity : fun.primOpApp.argsLeft;
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if (argsLeft == 1) {
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/* We have all the arguments, so call the primop. First
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find the primop. */
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Value * primOp = &fun;
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while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
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assert(primOp->type == tPrimOp);
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unsigned int arity = primOp->primOp.arity;
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/* Put all the arguments in an array. */
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Value * vArgs[arity];
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unsigned int n = arity - 1;
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vArgs[n--] = &arg;
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for (Value * arg = &fun; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
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vArgs[n--] = arg->primOpApp.right;
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/* And call the primop. */
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primOp->primOp.fun(*this, vArgs, v);
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} else {
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Value * v2 = allocValues(2);
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v2[0] = fun;
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v2[1] = arg;
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v.type = tPrimOpApp;
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v.primOpApp.left = &v2[0];
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v.primOpApp.right = &v2[1];
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v.primOpApp.argsLeft = argsLeft - 1;
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}
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return;
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}
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if (fun.type != tLambda)
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throwTypeError("attempt to call something which is neither a function nor a primop (built-in operation) but %1%",
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showType(fun));
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Env & env2(allocEnv());
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env2.up = fun.lambda.env;
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ATermList formals; ATerm ellipsis, name;
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if (matchVarPat(fun.lambda.pat, name)) {
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Value & vArg = env2.bindings[name];
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nrValues++;
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vArg = arg;
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}
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else if (matchAttrsPat(fun.lambda.pat, formals, ellipsis, name)) {
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forceAttrs(arg);
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if (name != sNoAlias) {
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env2.bindings[name] = arg;
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nrValues++;
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}
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/* For each formal argument, get the actual argument. If
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there is no matching actual argument but the formal
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argument has a default, use the default. */
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unsigned int attrsUsed = 0;
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for (ATermIterator i(formals); i; ++i) {
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Expr def; Sym name;
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DefaultValue def2;
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if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
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Bindings::iterator j = arg.attrs->find(name);
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Value & v = env2.bindings[name];
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nrValues++;
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if (j == arg.attrs->end()) {
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if (!matchDefaultValue(def2, def)) def = 0;
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if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
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% aterm2String(name));
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mkThunk(v, env2, def);
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} else {
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attrsUsed++;
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v.type = tCopy;
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v.val = &j->second;
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}
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}
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/* Check that each actual argument is listed as a formal
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argument (unless the attribute match specifies a `...').
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TODO: show the names of the expected/unexpected
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arguments. */
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if (ellipsis == eFalse && attrsUsed != arg.attrs->size())
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throw TypeError("function called with unexpected argument");
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}
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else abort();
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eval(env2, fun.lambda.body, v);
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}
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void EvalState::eval(Expr e, Value & v)
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{
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eval(baseEnv, e, v);
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@ -567,6 +567,8 @@ void EvalState::forceValue(Value & v)
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forceValue(*v.val);
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v = *v.val;
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}
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else if (v.type == tApp)
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callFunction(*v.app.left, *v.app.right, v);
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else if (v.type == tBlackhole)
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throw EvalError("infinite recursion encountered");
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}
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@ -597,6 +599,14 @@ void EvalState::forceList(Value & v)
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}
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void EvalState::forceFunction(Value & v)
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{
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forceValue(v);
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if (v.type != tLambda && v.type != tPrimOp && v.type != tPrimOpApp)
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throw TypeError(format("value is %1% while a function was expected") % showType(v));
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}
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string EvalState::coerceToString(Value & v, PathSet & context,
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bool coerceMore, bool copyToStore)
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{
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@ -36,6 +36,7 @@ typedef enum {
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tAttrs,
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tList,
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tThunk,
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tApp,
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tLambda,
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tCopy,
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tBlackhole,
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@ -68,6 +69,9 @@ struct Value
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Env * env;
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Expr expr;
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} thunk;
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struct {
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Value * left, * right;
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} app;
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struct {
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Env * env;
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Pattern pat;
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@ -161,13 +165,16 @@ struct EvalState
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void strictEval(Env & env, Expr e, Value & v);
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/* If `v' is a thunk, enter it and overwrite `v' with the result
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of the evaluation of the thunk. Otherwise, this is a no-op. */
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of the evaluation of the thunk. If `v' is a delayed function
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application, call the function and overwrite `v' with the
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result. Otherwise, this is a no-op. */
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void forceValue(Value & v);
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/* Force `v', and then verify that it has the expected type. */
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int forceInt(Value & v);
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void forceAttrs(Value & v);
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void forceList(Value & v);
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void forceFunction(Value & v); // either lambda or primop
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/* String coercion. Converts strings, paths and derivations to a
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string. If `coerceMore' is set, also converts nulls, integers,
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@ -196,6 +203,10 @@ private:
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elements and attributes are compared recursively. */
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bool eqValues(Value & v1, Value & v2);
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void callFunction(Value & fun, Value & arg, Value & v);
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public:
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/* Allocation primitives. */
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Value * allocValues(unsigned int count);
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Env & allocEnv();
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@ -913,22 +913,28 @@ static Expr prim_tail(EvalState & state, const ATermVector & args)
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throw Error("`tail' called on an empty list");
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return makeList(ATgetNext(list));
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}
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#endif
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/* Apply a function to every element of a list. */
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static Expr prim_map(EvalState & state, const ATermVector & args)
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static void prim_map(EvalState & state, Value * * args, Value & v)
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{
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Expr fun = evalExpr(state, args[0]);
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ATermList list = evalList(state, args[1]);
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state.forceFunction(*args[0]);
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state.forceList(*args[1]);
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ATermList res = ATempty;
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for (ATermIterator i(list); i; ++i)
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res = ATinsert(res, makeCall(fun, *i));
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v.type = tList;
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v.list.length = args[1]->list.length;
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v.list.elems = state.allocValues(v.list.length);
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return makeList(ATreverse(res));
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for (unsigned int n = 0; n < v.list.length; ++n) {
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v.list.elems[n].type = tApp;
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v.list.elems[n].app.left = args[0];
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v.list.elems[n].app.right = &args[1]->list.elems[n];
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}
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}
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#if 0
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/* Return the length of a list. This is an O(1) time operation. */
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static Expr prim_length(EvalState & state, const ATermVector & args)
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{
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@ -1189,7 +1195,9 @@ void EvalState::createBaseEnv()
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addPrimOp("__head", 1, prim_head);
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#if 0
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addPrimOp("__tail", 1, prim_tail);
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#endif
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addPrimOp("map", 2, prim_map);
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#if 0
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addPrimOp("__length", 1, prim_length);
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#endif
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