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Don't use any syntactic sugar for dynamic attrs

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This doesn't change any functionality but moves some behavior out of the
parser and into the evaluator in order to simplify the code.

Signed-off-by: Shea Levy <shea@shealevy.com>
This commit is contained in:
Shea Levy 2013-12-31 23:56:26 +00:00
parent 6f3a51809a
commit cd49fe4f9b
4 changed files with 68 additions and 128 deletions
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20
src/libexpr/eval.cc
View file

@ -129,6 +129,18 @@ string showType(const Value & v)
}
Symbol getName(const AttrName & name, EvalState & state, Env & env) {
if (name.symbol.set()) {
return name.symbol;
} else {
Value nameValue;
name.expr->eval(state, env, nameValue);
state.forceStringNoCtx(nameValue);
return state.symbols.create(nameValue.string.s);
}
}
EvalState::EvalState()
: sWith(symbols.create("<with>"))
, sOutPath(symbols.create("outPath"))
@ -683,17 +695,18 @@ void ExprSelect::eval(EvalState & state, Env & env, Value & v)
foreach (AttrPath::const_iterator, i, attrPath) {
nrLookups++;
Bindings::iterator j;
Symbol name = getName(*i, state, env);
if (def) {
state.forceValue(*vAttrs);
if (vAttrs->type != tAttrs ||
(j = vAttrs->attrs->find(*i)) == vAttrs->attrs->end())
(j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
{
def->eval(state, env, v);
return;
}
} else {
state.forceAttrs(*vAttrs);
if ((j = vAttrs->attrs->find(*i)) == vAttrs->attrs->end())
if ((j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
throwEvalError("attribute `%1%' missing", showAttrPath(attrPath));
}
vAttrs = j->value;
@ -724,8 +737,9 @@ void ExprOpHasAttr::eval(EvalState & state, Env & env, Value & v)
foreach (AttrPath::const_iterator, i, attrPath) {
state.forceValue(*vAttrs);
Bindings::iterator j;
Symbol name = getName(*i, state, env);
if (vAttrs->type != tAttrs ||
(j = vAttrs->attrs->find(*i)) == vAttrs->attrs->end())
(j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
{
mkBool(v, false);
return;

21
src/libexpr/nixexpr.cc
View file

@ -155,12 +155,19 @@ std::ostream & operator << (std::ostream & str, const Pos & pos)
string showAttrPath(const AttrPath & attrPath)
{
string s;
std::ostringstream out;
bool first = true;
foreach (AttrPath::const_iterator, i, attrPath) {
if (!s.empty()) s += '.';
s += *i;
if (!first)
out << '.';
else
first = false;
if (i->symbol.set())
out << i->symbol;
else
out << "\"${" << *i->expr << "}\"";
}
return s;
return out.str();
}
@ -220,11 +227,17 @@ void ExprSelect::bindVars(const StaticEnv & env)
{
e->bindVars(env);
if (def) def->bindVars(env);
foreach (AttrPath::iterator, i, attrPath)
if (!i->symbol.set())
i->expr->bindVars(env);
}
void ExprOpHasAttr::bindVars(const StaticEnv & env)
{
e->bindVars(env);
foreach (AttrPath::iterator, i, attrPath)
if (!i->symbol.set())
i->expr->bindVars(env);
}
void ExprAttrs::bindVars(const StaticEnv & env)

13
src/libexpr/nixexpr.hh
View file

@ -50,10 +50,19 @@ struct Env;
struct Value;
struct EvalState;
struct StaticEnv;
struct Expr;
/* An attribute path is a sequence of attribute names. */
typedef vector<Symbol> AttrPath;
struct AttrName
{
Symbol symbol;
Expr *expr;
AttrName(const Symbol & s) : symbol(s) {};
AttrName(Expr *e) : expr(e) {};
};
typedef std::vector<AttrName> AttrPath;
string showAttrPath(const AttrPath & attrPath);
@ -138,7 +147,7 @@ struct ExprSelect : Expr
Expr * e, * def;
AttrPath attrPath;
ExprSelect(Expr * e, const AttrPath & attrPath, Expr * def) : e(e), def(def), attrPath(attrPath) { };
ExprSelect(Expr * e, const Symbol & name) : e(e), def(0) { attrPath.push_back(name); };
ExprSelect(Expr * e, const Symbol & name) : e(e), def(0) { attrPath.push_back(AttrName(name)); };
COMMON_METHODS
};

142
src/libexpr/parser.y
View file

@ -39,15 +39,6 @@ namespace nix {
{ };
};
struct AttrName
{
Symbol symbol;
Expr *expr;
AttrName(const Symbol & s) : symbol(s) {};
AttrName(Expr *e) : expr(e) {};
};
typedef std::vector<AttrName> AttrNames;
}
#define YY_DECL int yylex \
@ -83,32 +74,28 @@ static void dupAttr(const AttrPath & attrPath, const Pos & pos, const Pos & prev
static void dupAttr(Symbol attr, const Pos & pos, const Pos & prevPos)
{
AttrPath attrPath; attrPath.push_back(attr);
throw ParseError(format("attribute `%1%' at %2% already defined at %3%")
% showAttrPath(attrPath) % pos % prevPos);
% attr % pos % prevPos);
}
static void addAttr(ExprAttrs * attrs, AttrNames & attrNames,
static void addAttr(ExprAttrs * attrs, AttrPath & attrPath,
Expr * e, const Pos & pos)
{
AttrPath path;
AttrNames::iterator i;
AttrPath::iterator i;
// All attrpaths have at least one attr
assert(!attrNames.empty());
for (i = attrNames.begin(); i + 1 < attrNames.end(); i++) {
assert(!attrPath.empty());
for (i = attrPath.begin(); i + 1 < attrPath.end(); i++) {
if (i->symbol.set()) {
path.push_back(i->symbol);
ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
if (j != attrs->attrs.end()) {
if (!j->second.inherited) {
ExprAttrs * attrs2 = dynamic_cast<ExprAttrs *>(j->second.e);
if (!attrs2) dupAttr(path, pos, j->second.pos);
if (!attrs2) dupAttr(attrPath, pos, j->second.pos);
attrs = attrs2;
} else
dupAttr(path, pos, j->second.pos);
dupAttr(attrPath, pos, j->second.pos);
} else {
path.clear();
ExprAttrs * nested = new ExprAttrs;
attrs->attrs[i->symbol] = ExprAttrs::AttrDef(nested, pos);
attrs = nested;
@ -122,7 +109,7 @@ static void addAttr(ExprAttrs * attrs, AttrNames & attrNames,
if (i->symbol.set()) {
ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
if (j != attrs->attrs.end()) {
dupAttr(path, pos, j->second.pos);
dupAttr(attrPath, pos, j->second.pos);
} else {
attrs->attrs[i->symbol] = ExprAttrs::AttrDef(e, pos);
e->setName(i->symbol);
@ -268,8 +255,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err
char * id; // !!! -> Symbol
char * path;
char * uri;
std::vector<nix::AttrName> * attrpath;
std::vector<nix::Symbol> * attrlist;
std::vector<nix::AttrName> * attrNames;
std::vector<nix::Expr *> * string_parts;
}
@ -279,8 +265,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err
%type <attrs> binds
%type <formals> formals
%type <formal> formal
%type <attrpath> attrpath
%type <attrlist> attrs
%type <attrNames> attrs attrpath
%type <string_parts> string_parts_interpolated ind_string_parts
%type <e> string_parts string_attr
%type <id> attr
@ -354,39 +339,7 @@ expr_op
| expr_op OR expr_op { $$ = new ExprOpOr($1, $3); }
| expr_op IMPL expr_op { $$ = new ExprOpImpl($1, $3); }
| expr_op UPDATE expr_op { $$ = new ExprOpUpdate($1, $3); }
| expr_op '?' attrpath
{ AttrPath path;
vector<AttrName>::iterator i;
$$ = $1;
// All attrpaths have at least one attr
assert(!$3->empty());
for (i = $3->begin(); i + 1 != $3->end(); i++) {
if (i->symbol.set()) {
path.push_back(i->symbol);
} else {
if (!path.empty()) {
$$ = new ExprSelect($$, path, new ExprAttrs());
path.clear();
}
$$ = new ExprIf(
new ExprOpAnd(
new ExprApp(new ExprBuiltin(data->symbols.create("isAttrs")), $$),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("hasAttr")), i->expr), $$)),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("getAttr")), i->expr), $$),
new ExprAttrs());
}
}
if (i->symbol.set()) {
path.push_back(i->symbol);
$$ = new ExprOpHasAttr($$, path);
} else {
if (!path.empty())
$$ = new ExprSelect($$, path, new ExprAttrs());
$$ = new ExprOpAnd(
new ExprApp(new ExprBuiltin(data->symbols.create("isAttrs")), $$),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("hasAttr")), i->expr), $$));
}
}
| expr_op '?' attrpath { $$ = new ExprOpHasAttr($1, *$3); }
| expr_op '+' expr_op
{ vector<Expr *> * l = new vector<Expr *>;
l->push_back($1);
@ -408,58 +361,9 @@ expr_app
expr_select
: expr_simple '.' attrpath
{ AttrPath path;
$$ = $1;
foreach (vector<AttrName>::iterator, i, *$3) {
if (i->symbol.set()) {
path.push_back(i->symbol);
} else {
if (!path.empty()) {
$$ = new ExprSelect($$, path, 0);
path.clear();
}
$$ = new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("getAttr")), i->expr), $$);
}
}
if (!path.empty())
$$ = new ExprSelect($$, path, 0);
}
{ $$ = new ExprSelect($1, *$3, 0); }
| expr_simple '.' attrpath OR_KW expr_select
{ AttrPath path;
vector<AttrName>::iterator i;
$$ = $1;
// All attrpaths have at least one attr
assert(!$3->empty());
for (i = $3->begin(); i + 1 != $3->end(); i++) {
if (i->symbol.set()) {
path.push_back(i->symbol);
} else {
if (!path.empty()) {
$$ = new ExprSelect($$, path, new ExprAttrs());
path.clear();
}
$$ = new ExprIf(
new ExprOpAnd(
new ExprApp(new ExprBuiltin(data->symbols.create("isAttrs")), $$),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("hasAttr")), i->expr), $$)),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("getAttr")), i->expr), $$),
new ExprAttrs());
}
}
if (i->symbol.set()) {
path.push_back(i->symbol);
$$ = new ExprSelect($$, path, $5);
} else {
if (!path.empty())
$$ = new ExprSelect($$, path, new ExprAttrs());
$$ = new ExprIf(
new ExprOpAnd(
new ExprApp(new ExprBuiltin(data->symbols.create("isAttrs")), $$),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("hasAttr")), i->expr), $$)),
new ExprApp(new ExprApp(new ExprBuiltin(data->symbols.create("getAttr")), i->expr), $$),
$5);
}
}
{ $$ = new ExprSelect($1, *$3, $5); }
| /* Backwards compatibility: because Nixpkgs has a rarely used
function named ‘or’, allow stuff like ‘map or [...]’. */
expr_simple OR_KW
@ -542,37 +446,37 @@ binds
| binds INHERIT attrs ';'
{ $$ = $1;
foreach (AttrPath::iterator, i, *$3) {
if ($$->attrs.find(*i) != $$->attrs.end())
dupAttr(*i, makeCurPos(@3, data), $$->attrs[*i].pos);
if ($$->attrs.find(i->symbol) != $$->attrs.end())
dupAttr(i->symbol, makeCurPos(@3, data), $$->attrs[i->symbol].pos);
Pos pos = makeCurPos(@3, data);
$$->attrs[*i] = ExprAttrs::AttrDef(new ExprVar(CUR_POS, *i), pos, true);
$$->attrs[i->symbol] = ExprAttrs::AttrDef(new ExprVar(CUR_POS, i->symbol), pos, true);
}
}
| binds INHERIT '(' expr ')' attrs ';'
{ $$ = $1;
/* !!! Should ensure sharing of the expression in $4. */
foreach (vector<Symbol>::iterator, i, *$6) {
if ($$->attrs.find(*i) != $$->attrs.end())
dupAttr(*i, makeCurPos(@6, data), $$->attrs[*i].pos);
$$->attrs[*i] = ExprAttrs::AttrDef(new ExprSelect($4, *i), makeCurPos(@6, data));
foreach (AttrPath::iterator, i, *$6) {
if ($$->attrs.find(i->symbol) != $$->attrs.end())
dupAttr(i->symbol, makeCurPos(@6, data), $$->attrs[i->symbol].pos);
$$->attrs[i->symbol] = ExprAttrs::AttrDef(new ExprSelect($4, i->symbol), makeCurPos(@6, data));
}
}
| { $$ = new ExprAttrs; }
;
attrs
: attrs attr { $$ = $1; $1->push_back(data->symbols.create($2)); /* !!! dangerous */ }
: attrs attr { $$ = $1; $1->push_back(AttrName(data->symbols.create($2))); }
| attrs string_attr
{ $$ = $1;
ExprString *str = dynamic_cast<ExprString *>($2);
if (str) {
$$->push_back(str->s);
$$->push_back(AttrName(str->s));
delete str;
} else
throw ParseError(format("dynamic attributes not allowed in inherit at %1%")
% makeCurPos(@2, data));
}
| { $$ = new vector<Symbol>; }
| { $$ = new AttrPath; }
;
attrpath