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* Implemented `map'.

This commit is contained in:
Eelco Dolstra 2010-03-30 13:47:59 +00:00
parent d78a05ab40
commit 5b72d8a749
4 changed files with 139 additions and 108 deletions
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2
src/libexpr/eval-test.cc
View File

@ -68,6 +68,8 @@ void run(Strings args)
doTest("let x = x; in if true || x then 1 else 2");
doTest("/etc/passwd");
doTest("import ./foo.nix");
doTest("map (x: __add 1 x) [ 1 2 3 ]");
doTest("map (__add 1) [ 1 2 3 ]");
}

210
src/libexpr/eval.cc
View File

@ -328,106 +328,9 @@ void EvalState::eval(Env & env, Expr e, Value & v)
Expr fun, arg;
if (matchCall(e, fun, arg)) {
eval(env, fun, v);
if (v.type == tPrimOp || v.type == tPrimOpApp) {
unsigned int argsLeft =
v.type == tPrimOp ? v.primOp.arity : v.primOpApp.argsLeft;
if (argsLeft == 1) {
/* We have all the arguments, so call the primop.
First find the primop. */
Value * primOp = &v;
while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
assert(primOp->type == tPrimOp);
unsigned int arity = primOp->primOp.arity;
Value vLastArg;
mkThunk(vLastArg, env, arg);
/* Put all the arguments in an array. */
Value * vArgs[arity];
unsigned int n = arity - 1;
vArgs[n--] = &vLastArg;
for (Value * arg = &v; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
vArgs[n--] = arg->primOpApp.right;
/* And call the primop. */
primOp->primOp.fun(*this, vArgs, v);
} else {
Value * v2 = allocValues(2);
v2[0] = v;
mkThunk(v2[1], env, arg);
v.type = tPrimOpApp;
v.primOpApp.left = &v2[0];
v.primOpApp.right = &v2[1];
v.primOpApp.argsLeft = argsLeft - 1;
}
return;
}
if (v.type != tLambda) throw TypeError("expected function");
Env & env2(allocEnv());
env2.up = &env;
ATermList formals; ATerm ellipsis;
if (matchVarPat(v.lambda.pat, name)) {
Value & vArg = env2.bindings[name];
nrValues++;
mkThunk(vArg, env, arg);
}
else if (matchAttrsPat(v.lambda.pat, formals, ellipsis, name)) {
Value * vArg;
Value vArg_;
if (name == sNoAlias)
vArg = &vArg_;
else {
vArg = &env2.bindings[name];
nrValues++;
}
eval(env, arg, *vArg);
forceAttrs(*vArg);
/* 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 def; Sym name;
DefaultValue def2;
if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
Bindings::iterator j = vArg->attrs->find(name);
Value & v = env2.bindings[name];
nrValues++;
if (j == vArg->attrs->end()) {
if (!matchDefaultValue(def2, def)) def = 0;
if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
% aterm2String(name));
mkThunk(v, env2, def);
} else {
attrsUsed++;
v.type = tCopy;
v.val = &j->second;
}
}
/* Check that each actual argument is listed as a formal
argument (unless the attribute match specifies a
`...'). TODO: show the names of the
expected/unexpected arguments. */
if (ellipsis == eFalse && attrsUsed != vArg->attrs->size())
throw TypeError("function called with unexpected argument");
}
else abort();
eval(env2, v.lambda.body, v);
Value vArg;
mkThunk(vArg, env, arg); // !!! should this be on the heap?
callFunction(v, vArg, v);
return;
}
@ -519,6 +422,103 @@ void EvalState::eval(Env & env, Expr e, Value & v)
}
void EvalState::callFunction(Value & fun, Value & arg, Value & v)
{
if (fun.type == tPrimOp || fun.type == tPrimOpApp) {
unsigned int argsLeft =
fun.type == tPrimOp ? fun.primOp.arity : fun.primOpApp.argsLeft;
if (argsLeft == 1) {
/* We have all the arguments, so call the primop. First
find the primop. */
Value * primOp = &fun;
while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
assert(primOp->type == tPrimOp);
unsigned int arity = primOp->primOp.arity;
/* Put all the arguments in an array. */
Value * vArgs[arity];
unsigned int n = arity - 1;
vArgs[n--] = &arg;
for (Value * arg = &fun; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
vArgs[n--] = arg->primOpApp.right;
/* And call the primop. */
primOp->primOp.fun(*this, vArgs, v);
} else {
Value * v2 = allocValues(2);
v2[0] = fun;
v2[1] = arg;
v.type = tPrimOpApp;
v.primOpApp.left = &v2[0];
v.primOpApp.right = &v2[1];
v.primOpApp.argsLeft = argsLeft - 1;
}
return;
}
if (fun.type != tLambda)
throwTypeError("attempt to call something which is neither a function nor a primop (built-in operation) but %1%",
showType(fun));
Env & env2(allocEnv());
env2.up = fun.lambda.env;
ATermList formals; ATerm ellipsis, name;
if (matchVarPat(fun.lambda.pat, name)) {
Value & vArg = env2.bindings[name];
nrValues++;
vArg = arg;
}
else if (matchAttrsPat(fun.lambda.pat, formals, ellipsis, name)) {
forceAttrs(arg);
if (name != sNoAlias) {
env2.bindings[name] = arg;
nrValues++;
}
/* 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 def; Sym name;
DefaultValue def2;
if (!matchFormal(*i, name, def2)) abort(); /* can't happen */
Bindings::iterator j = arg.attrs->find(name);
Value & v = env2.bindings[name];
nrValues++;
if (j == arg.attrs->end()) {
if (!matchDefaultValue(def2, def)) def = 0;
if (def == 0) throw TypeError(format("the argument named `%1%' required by the function is missing")
% aterm2String(name));
mkThunk(v, env2, def);
} else {
attrsUsed++;
v.type = tCopy;
v.val = &j->second;
}
}
/* Check that each actual argument is listed as a formal
argument (unless the attribute match specifies a `...').
TODO: show the names of the expected/unexpected
arguments. */
if (ellipsis == eFalse && attrsUsed != arg.attrs->size())
throw TypeError("function called with unexpected argument");
}
else abort();
eval(env2, fun.lambda.body, v);
}
void EvalState::eval(Expr e, Value & v)
{
eval(baseEnv, e, v);
@ -567,6 +567,8 @@ void EvalState::forceValue(Value & v)
forceValue(*v.val);
v = *v.val;
}
else if (v.type == tApp)
callFunction(*v.app.left, *v.app.right, v);
else if (v.type == tBlackhole)
throw EvalError("infinite recursion encountered");
}
@ -597,6 +599,14 @@ void EvalState::forceList(Value & v)
}
void EvalState::forceFunction(Value & v)
{
forceValue(v);
if (v.type != tLambda && v.type != tPrimOp && v.type != tPrimOpApp)
throw TypeError(format("value is %1% while a function was expected") % showType(v));
}
string EvalState::coerceToString(Value & v, PathSet & context,
bool coerceMore, bool copyToStore)
{

13
src/libexpr/eval.hh
View File

@ -36,6 +36,7 @@ typedef enum {
tAttrs,
tList,
tThunk,
tApp,
tLambda,
tCopy,
tBlackhole,
@ -68,6 +69,9 @@ struct Value
Env * env;
Expr expr;
} thunk;
struct {
Value * left, * right;
} app;
struct {
Env * env;
Pattern pat;
@ -161,13 +165,16 @@ struct EvalState
void strictEval(Env & env, Expr e, Value & v);
/* If `v' is a thunk, enter it and overwrite `v' with the result
of the evaluation of the thunk. Otherwise, this is a no-op. */
of the evaluation of the thunk. If `v' is a delayed function
application, call the function and overwrite `v' with the
result. Otherwise, this is a no-op. */
void forceValue(Value & v);
/* Force `v', and then verify that it has the expected type. */
int forceInt(Value & v);
void forceAttrs(Value & v);
void forceList(Value & v);
void forceFunction(Value & v); // either lambda or primop
/* String coercion. Converts strings, paths and derivations to a
string. If `coerceMore' is set, also converts nulls, integers,
@ -196,6 +203,10 @@ private:
elements and attributes are compared recursively. */
bool eqValues(Value & v1, Value & v2);
void callFunction(Value & fun, Value & arg, Value & v);
public:
/* Allocation primitives. */
Value * allocValues(unsigned int count);
Env & allocEnv();

22
src/libexpr/primops.cc
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@ -913,22 +913,28 @@ static Expr prim_tail(EvalState & state, const ATermVector & args)
throw Error("`tail' called on an empty list");
return makeList(ATgetNext(list));
}
#endif
/* Apply a function to every element of a list. */
static Expr prim_map(EvalState & state, const ATermVector & args)
static void prim_map(EvalState & state, Value * * args, Value & v)
{
Expr fun = evalExpr(state, args[0]);
ATermList list = evalList(state, args[1]);
state.forceFunction(*args[0]);
state.forceList(*args[1]);
ATermList res = ATempty;
for (ATermIterator i(list); i; ++i)
res = ATinsert(res, makeCall(fun, *i));
v.type = tList;
v.list.length = args[1]->list.length;
v.list.elems = state.allocValues(v.list.length);
return makeList(ATreverse(res));
for (unsigned int n = 0; n < v.list.length; ++n) {
v.list.elems[n].type = tApp;
v.list.elems[n].app.left = args[0];
v.list.elems[n].app.right = &args[1]->list.elems[n];
}
}
#if 0
/* Return the length of a list. This is an O(1) time operation. */
static Expr prim_length(EvalState & state, const ATermVector & args)
{
@ -1189,7 +1195,9 @@ void EvalState::createBaseEnv()
addPrimOp("__head", 1, prim_head);
#if 0
addPrimOp("__tail", 1, prim_tail);
#endif
addPrimOp("map", 2, prim_map);
#if 0
addPrimOp("__length", 1, prim_length);
#endif