lix/src/libexpr/nixexpr.cc
2022-05-19 12:44:40 -06:00

587 lines
15 KiB
C++

#include "nixexpr.hh"
#include "derivations.hh"
#include "eval.hh"
#include "symbol-table.hh"
#include "util.hh"
#include <cstdlib>
namespace nix {
/* Launch the nix debugger */
std::function<void(EvalState & evalState,const Error * error, const Env & env, const Expr & expr)> debuggerHook;
/* Displaying abstract syntax trees. */
static void showString(std::ostream & str, std::string_view s)
{
str << '"';
for (auto c : s)
if (c == '"' || c == '\\' || c == '$') str << "\\" << c;
else if (c == '\n') str << "\\n";
else if (c == '\r') str << "\\r";
else if (c == '\t') str << "\\t";
else str << c;
str << '"';
}
std::ostream & operator <<(std::ostream & str, const SymbolStr & symbol)
{
std::string_view s = symbol;
if (s.empty())
str << "\"\"";
else if (s == "if") // FIXME: handle other keywords
str << '"' << s << '"';
else {
char c = s[0];
if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_')) {
showString(str, s);
return str;
}
for (auto c : s)
if (!((c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
c == '_' || c == '\'' || c == '-')) {
showString(str, s);
return str;
}
str << s;
}
return str;
}
void Expr::show(const SymbolTable & symbols, std::ostream & str) const
{
abort();
}
void ExprInt::show(const SymbolTable & symbols, std::ostream & str) const
{
str << n;
}
void ExprFloat::show(const SymbolTable & symbols, std::ostream & str) const
{
str << nf;
}
void ExprString::show(const SymbolTable & symbols, std::ostream & str) const
{
showString(str, s);
}
void ExprPath::show(const SymbolTable & symbols, std::ostream & str) const
{
str << s;
}
void ExprVar::show(const SymbolTable & symbols, std::ostream & str) const
{
str << symbols[name];
}
void ExprSelect::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "(";
e->show(symbols, str);
str << ")." << showAttrPath(symbols, attrPath);
if (def) {
str << " or (";
def->show(symbols, str);
str << ")";
}
}
void ExprOpHasAttr::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "((";
e->show(symbols, str);
str << ") ? " << showAttrPath(symbols, attrPath) << ")";
}
void ExprAttrs::show(const SymbolTable & symbols, std::ostream & str) const
{
if (recursive) str << "rec ";
str << "{ ";
typedef const decltype(attrs)::value_type * Attr;
std::vector<Attr> sorted;
for (auto & i : attrs) sorted.push_back(&i);
std::sort(sorted.begin(), sorted.end(), [&](Attr a, Attr b) {
std::string_view sa = symbols[a->first], sb = symbols[b->first];
return sa < sb;
});
for (auto & i : sorted) {
if (i->second.inherited)
str << "inherit " << symbols[i->first] << " " << "; ";
else {
str << symbols[i->first] << " = ";
i->second.e->show(symbols, str);
str << "; ";
}
}
for (auto & i : dynamicAttrs) {
str << "\"${";
i.nameExpr->show(symbols, str);
str << "}\" = ";
i.valueExpr->show(symbols, str);
str << "; ";
}
str << "}";
}
void ExprList::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "[ ";
for (auto & i : elems) {
str << "(";
i->show(symbols, str);
str << ") ";
}
str << "]";
}
void ExprLambda::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "(";
if (hasFormals()) {
str << "{ ";
bool first = true;
for (auto & i : formals->formals) {
if (first) first = false; else str << ", ";
str << symbols[i.name];
if (i.def) {
str << " ? ";
i.def->show(symbols, str);
}
}
if (formals->ellipsis) {
if (!first) str << ", ";
str << "...";
}
str << " }";
if (arg) str << " @ ";
}
if (arg) str << symbols[arg];
str << ": ";
body->show(symbols, str);
str << ")";
}
void ExprCall::show(const SymbolTable & symbols, std::ostream & str) const
{
str << '(';
fun->show(symbols, str);
for (auto e : args) {
str << ' ';
e->show(symbols, str);
}
str << ')';
}
void ExprLet::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "(let ";
for (auto & i : attrs->attrs)
if (i.second.inherited) {
str << "inherit " << symbols[i.first] << "; ";
}
else {
str << symbols[i.first] << " = ";
i.second.e->show(symbols, str);
str << "; ";
}
str << "in ";
body->show(symbols, str);
str << ")";
}
void ExprWith::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "(with ";
attrs->show(symbols, str);
str << "; ";
body->show(symbols, str);
str << ")";
}
void ExprIf::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "(if ";
cond->show(symbols, str);
str << " then ";
then->show(symbols, str);
str << " else ";
else_->show(symbols, str);
str << ")";
}
void ExprAssert::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "assert ";
cond->show(symbols, str);
str << "; ";
body->show(symbols, str);
}
void ExprOpNot::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "(! ";
e->show(symbols, str);
str << ")";
}
void ExprConcatStrings::show(const SymbolTable & symbols, std::ostream & str) const
{
bool first = true;
str << "(";
for (auto & i : *es) {
if (first) first = false; else str << " + ";
i.second->show(symbols, str);
}
str << ")";
}
void ExprPos::show(const SymbolTable & symbols, std::ostream & str) const
{
str << "__curPos";
}
std::ostream & operator << (std::ostream & str, const Pos & pos)
{
if (!pos)
str << "undefined position";
else
{
auto f = format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%");
switch (pos.origin) {
case foFile:
f % (const std::string &) pos.file;
break;
case foStdin:
case foString:
f % "(string)";
break;
default:
throw Error("unhandled Pos origin!");
}
str << (f % pos.line % pos.column).str();
}
return str;
}
std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
{
std::ostringstream out;
bool first = true;
for (auto & i : attrPath) {
if (!first) out << '.'; else first = false;
if (i.symbol)
out << symbols[i.symbol];
else {
out << "\"${";
i.expr->show(symbols, out);
out << "}\"";
}
}
return out.str();
}
/* Computing levels/displacements for variables. */
void Expr::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
abort();
}
void ExprInt::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
}
void ExprFloat::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
}
void ExprString::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
}
void ExprPath::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
}
void ExprVar::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
/* Check whether the variable appears in the environment. If so,
set its level and displacement. */
const StaticEnv * curEnv;
Level level;
int withLevel = -1;
for (curEnv = env.get(), level = 0; curEnv; curEnv = curEnv->up, level++) {
if (curEnv->isWith) {
if (withLevel == -1) withLevel = level;
} else {
auto i = curEnv->find(name);
if (i != curEnv->vars.end()) {
fromWith = false;
this->level = level;
displ = i->second;
return;
}
}
}
/* Otherwise, the variable must be obtained from the nearest
enclosing `with'. If there is no `with', then we can issue an
"undefined variable" error now. */
if (withLevel == -1)
throw UndefinedVarError({
.msg = hintfmt("undefined variable '%1%'", es.symbols[name]),
.errPos = es.positions[pos]
});
fromWith = true;
this->level = withLevel;
}
void ExprSelect::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
e->bindVars(es, env);
if (def) def->bindVars(es, env);
for (auto & i : attrPath)
if (!i.symbol)
i.expr->bindVars(es, env);
}
void ExprOpHasAttr::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
e->bindVars(es, env);
for (auto & i : attrPath)
if (!i.symbol)
i.expr->bindVars(es, env);
}
void ExprAttrs::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
if (recursive) {
auto newEnv = std::make_shared<StaticEnv>(false, env.get(), recursive ? attrs.size() : 0);
Displacement displ = 0;
for (auto & i : attrs)
newEnv->vars.emplace_back(i.first, i.second.displ = displ++);
// No need to sort newEnv since attrs is in sorted order.
for (auto & i : attrs)
i.second.e->bindVars(es, i.second.inherited ? env : newEnv);
for (auto & i : dynamicAttrs) {
i.nameExpr->bindVars(es, newEnv);
i.valueExpr->bindVars(es, newEnv);
}
}
else {
for (auto & i : attrs)
i.second.e->bindVars(es, env);
for (auto & i : dynamicAttrs) {
i.nameExpr->bindVars(es, env);
i.valueExpr->bindVars(es, env);
}
}
}
void ExprList::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
for (auto & i : elems)
i->bindVars(es, env);
}
void ExprLambda::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
auto newEnv = std::make_shared<StaticEnv>(
false, env.get(),
(hasFormals() ? formals->formals.size() : 0) +
(!arg ? 0 : 1));
Displacement displ = 0;
if (arg) newEnv->vars.emplace_back(arg, displ++);
if (hasFormals()) {
for (auto & i : formals->formals)
newEnv->vars.emplace_back(i.name, displ++);
newEnv->sort();
for (auto & i : formals->formals)
if (i.def) i.def->bindVars(es, newEnv);
}
body->bindVars(es, newEnv);
}
void ExprCall::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
fun->bindVars(es, env);
for (auto e : args)
e->bindVars(es, env);
}
void ExprLet::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
auto newEnv = std::make_shared<StaticEnv>(false, env.get(), attrs->attrs.size());
Displacement displ = 0;
for (auto & i : attrs->attrs)
newEnv->vars.emplace_back(i.first, i.second.displ = displ++);
// No need to sort newEnv since attrs->attrs is in sorted order.
for (auto & i : attrs->attrs)
i.second.e->bindVars(es, i.second.inherited ? env : newEnv);
body->bindVars(es, newEnv);
}
void ExprWith::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
/* Does this `with' have an enclosing `with'? If so, record its
level so that `lookupVar' can look up variables in the previous
`with' if this one doesn't contain the desired attribute. */
const StaticEnv * curEnv;
Level level;
prevWith = 0;
for (curEnv = env.get(), level = 1; curEnv; curEnv = curEnv->up, level++)
if (curEnv->isWith) {
prevWith = level;
break;
}
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
attrs->bindVars(es, env);
auto newEnv = std::make_shared<StaticEnv>(true, env.get());
body->bindVars(es, newEnv);
}
void ExprIf::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
cond->bindVars(es, env);
then->bindVars(es, env);
else_->bindVars(es, env);
}
void ExprAssert::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
cond->bindVars(es, env);
body->bindVars(es, env);
}
void ExprOpNot::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
e->bindVars(es, env);
}
void ExprConcatStrings::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
for (auto & i : *this->es)
i.second->bindVars(es, env);
}
void ExprPos::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
{
if (debuggerHook)
es.exprEnvs.insert(std::make_pair(this, env));
}
/* Storing function names. */
void Expr::setName(Symbol name)
{
}
void ExprLambda::setName(Symbol name)
{
this->name = name;
body->setName(name);
}
std::string ExprLambda::showNamePos(const EvalState & state) const
{
std::string id(name
? concatStrings("'", state.symbols[name], "'")
: "anonymous function");
return fmt("%1% at %2%", id, state.positions[pos]);
}
/* Symbol table. */
size_t SymbolTable::totalSize() const
{
size_t n = 0;
dump([&] (const std::string & s) { n += s.size(); });
return n;
}
}