* Implemented withs.

This commit is contained in:
Eelco Dolstra 2010-04-14 15:01:04 +00:00
parent 9985230c00
commit 110d155778
4 changed files with 38 additions and 15 deletions

View file

@ -72,7 +72,8 @@ void run(Strings args)
doTest(state, "let { x = 1; body = x; }");
doTest(state, "with { x = 1; }; x");
doTest(state, "let x = 2; in with { x = 1; }; x"); // => 2
doTest(state, "with { x = 1; }; with { x = 2; }; x"); // => 1
doTest(state, "with { x = 1; }; with { x = 2; }; x"); // => 2
doTest(state, "with { x = 1; }; with { y = 2; }; x"); // => 1
doTest(state, "[ 1 2 3 ]");
doTest(state, "[ 1 2 ] ++ [ 3 4 5 ]");
doTest(state, "123 == 123");

View file

@ -253,8 +253,6 @@ Value * EvalState::lookupVar(Env * env, const Symbol & name)
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
}
throwEvalError("urgh! undefined variable `%1%'", name);
#endif
}
@ -483,13 +481,15 @@ void ExprList::eval(EvalState & state, Env & env, Value & v)
void ExprVar::eval(EvalState & state, Env & env, Value & v)
{
printMsg(lvlError, format("eval var %1% %2% %3%") % fromWith % level % displ);
if (fromWith) {
abort();
} else {
Env * env2 = &env;
for (unsigned int l = level; l; --l, env2 = env2->up) ;
if (fromWith) {
Bindings::iterator j = env2->values[0].attrs->find(name);
if (j == env2->values[0].attrs->end())
throwEvalError("undefined variable `%1%'", name);
v = j->second;
} else {
state.forceValue(env2->values[displ]);
v = env2->values[displ];
}
@ -655,17 +655,26 @@ void EvalState::autoCallFunction(const Bindings & args, Value & fun, Value & res
void ExprWith::eval(EvalState & state, Env & env, Value & v)
{
abort();
#if 0
Env & env2(state.allocEnv());
Env & env2(state.allocEnv(1));
env2.up = &env;
Value & vAttrs = env2.bindings[state.sWith];
state.eval(env, attrs, vAttrs);
state.forceAttrs(vAttrs);
state.eval(env, attrs, env2.values[0]);
state.forceAttrs(env2.values[0]);
/* If there is an enclosing `with', copy all attributes that don't
appear in this `with'. */
if (prevWith != -1) {
Env * env3 = &env;
for (unsigned int l = prevWith; l; --l, env3 = env3->up) ;
foreach (Bindings::iterator, i, *env3->values[0].attrs) {
Bindings::iterator j = env2.values[0].attrs->find(i->first);
if (j == env2.values[0].attrs->end())
(*env2.values[0].attrs)[i->first] = i->second; // !!! sharing
}
}
state.eval(env2, body, v);
#endif
}

View file

@ -264,6 +264,18 @@ void ExprLet::bindVars(const StaticEnv & env)
void ExprWith::bindVars(const StaticEnv & env)
{
/* Does this `with' have an enclosing `with'? If so, record its
level so that we can copy the attributes of the enclosing
`with'. */
const StaticEnv * curEnv;
unsigned int level;
prevWith = -1;
for (curEnv = &env, level = 0; curEnv; curEnv = curEnv->up, level++)
if (curEnv->isWith) {
prevWith = level;
break;
}
attrs->bindVars(env);
StaticEnv newEnv(true, &env);
body->bindVars(newEnv);

View file

@ -170,6 +170,7 @@ struct ExprWith : Expr
{
Pos pos;
Expr * attrs, * body;
int prevWith;
ExprWith(const Pos & pos, Expr * attrs, Expr * body) : pos(pos), attrs(attrs), body(body) { };
COMMON_METHODS
};