diff options
Diffstat (limited to 'third_party/nix/src/libexpr/nixexpr.cc')
| -rw-r--r-- | third_party/nix/src/libexpr/nixexpr.cc | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/nixexpr.cc b/third_party/nix/src/libexpr/nixexpr.cc new file mode 100644 index 000000000000..391f0682059c --- /dev/null +++ b/third_party/nix/src/libexpr/nixexpr.cc @@ -0,0 +1,414 @@ +#include "libexpr/nixexpr.hh" + +#include <cstdlib> +#include <variant> + +#include "libstore/derivations.hh" +#include "libutil/util.hh" +#include "libutil/visitor.hh" + +namespace nix { + +/* Displaying abstract syntax trees. */ + +std::ostream& operator<<(std::ostream& str, const Expr& e) { + e.show(str); + return str; +} + +static void showString(std::ostream& str, const std::string& s) { + str << '"'; + for (auto c : std::string(s)) { + if (c == '"' || c == '\\' || c == '$') { + str << "\\" << c; + } else if (c == '\n') { + str << "\\n"; + } else if (c == '\r') { + str << "\\r"; + } else if (c == '\t') { + str << "\\t"; + } else { + str << c; + } + } + str << '"'; +} + +static void showId(std::ostream& str, const std::string& s) { + if (s.empty()) { + str << "\"\""; + } else if (s == "if") { // FIXME: handle other keywords + str << '"' << s << '"'; + } else { + char c = s[0]; + if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_')) { + showString(str, s); + return; + } + for (auto c : s) { + if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || + (c >= '0' && c <= '9') || c == '_' || c == '\'' || c == '-')) { + showString(str, s); + return; + } + } + str << s; + } +} + +std::ostream& operator<<(std::ostream& str, const Symbol& sym) { + showId(str, *sym.s); + return str; +} + +void Expr::show(std::ostream& str) const { abort(); } + +void ExprInt::show(std::ostream& str) const { str << n; } + +void ExprFloat::show(std::ostream& str) const { str << nf; } + +void ExprString::show(std::ostream& str) const { showString(str, s); } + +void ExprPath::show(std::ostream& str) const { str << s; } + +void ExprVar::show(std::ostream& str) const { str << name; } + +void ExprSelect::show(std::ostream& str) const { + str << "(" << *e << ")." << showAttrPath(attrPath); + if (def != nullptr) { + str << " or (" << *def << ")"; + } +} + +void ExprOpHasAttr::show(std::ostream& str) const { + str << "((" << *e << ") ? " << showAttrPath(attrPath) << ")"; +} + +void ExprAttrs::show(std::ostream& str) const { + if (recursive) { + str << "rec "; + } + str << "{ "; + for (auto& i : attrs) { + if (i.second.inherited) { + str << "inherit " << i.first << " " + << "; "; + } else { + str << i.first << " = " << *i.second.e << "; "; + } + } + for (auto& i : dynamicAttrs) { + str << "\"${" << *i.nameExpr << "}\" = " << *i.valueExpr << "; "; + } + str << "}"; +} + +void ExprList::show(std::ostream& str) const { + str << "[ "; + for (auto& i : elems) { + str << "(" << *i << ") "; + } + str << "]"; +} + +void ExprLambda::show(std::ostream& str) const { + str << "("; + if (matchAttrs) { + str << "{ "; + bool first = true; + for (auto& i : formals->formals) { + if (first) { + first = false; + } else { + str << ", "; + } + str << i.name; + if (i.def != nullptr) { + str << " ? " << *i.def; + } + } + if (formals->ellipsis) { + if (!first) { + str << ", "; + } + str << "..."; + } + str << " }"; + if (!arg.empty()) { + str << " @ "; + } + } + if (!arg.empty()) { + str << arg; + } + str << ": " << *body << ")"; +} + +void ExprLet::show(std::ostream& str) const { + str << "(let "; + for (auto& i : attrs->attrs) { + if (i.second.inherited) { + str << "inherit " << i.first << "; "; + } else { + str << i.first << " = " << *i.second.e << "; "; + } + } + str << "in " << *body << ")"; +} + +void ExprWith::show(std::ostream& str) const { + str << "(with " << *attrs << "; " << *body << ")"; +} + +void ExprIf::show(std::ostream& str) const { + str << "(if " << *cond << " then " << *then << " else " << *else_ << ")"; +} + +void ExprAssert::show(std::ostream& str) const { + str << "assert " << *cond << "; " << *body; +} + +void ExprOpNot::show(std::ostream& str) const { str << "(! " << *e << ")"; } + +void ExprConcatStrings::show(std::ostream& str) const { + bool first = true; + str << "("; + for (auto& i : *es) { + if (first) { + first = false; + } else { + str << " + "; + } + str << *i; + } + str << ")"; +} + +void ExprPos::show(std::ostream& str) const { str << "__curPos"; } + +std::ostream& operator<<(std::ostream& str, const Pos& pos) { + if (!pos || !pos.file.has_value()) { + str << "undefined position"; + } else { + str << (format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%") % + std::string(pos.file.value()) % pos.line % pos.column) + .str(); + } + return str; +} + +std::string showAttrPath(const AttrPath& attrPath) { + std::ostringstream out; + bool first = true; + for (auto& attr : attrPath) { + if (!first) { + out << '.'; + } else { + first = false; + } + + std::visit(util::overloaded{ + [&](const Symbol& sym) { out << sym; }, + [&](const Expr* expr) { out << "\"${" << *expr << "}\""; }}, + attr); + } + return out.str(); +} + +Pos noPos; + +/* Computing levels/displacements for variables. */ + +void Expr::bindVars(const StaticEnv& env) { abort(); } + +void ExprInt::bindVars(const StaticEnv& env) {} + +void ExprFloat::bindVars(const StaticEnv& env) {} + +void ExprString::bindVars(const StaticEnv& env) {} + +void ExprPath::bindVars(const StaticEnv& env) {} + +void ExprVar::bindVars(const StaticEnv& env) { + /* Check whether the variable appears in the environment. If so, + set its level and displacement. */ + const StaticEnv* curEnv; + unsigned int level; + std::optional<unsigned int> withLevel = std::nullopt; + for (curEnv = &env, level = 0; curEnv != nullptr; + curEnv = curEnv->up, level++) { + if (curEnv->isWith) { + if (!withLevel.has_value()) { + withLevel = level; + } + } else { + auto i = curEnv->vars.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.has_value()) { + throw UndefinedVarError(format("undefined variable '%1%' at %2%") % name % + pos); + } + + fromWith = true; + this->level = withLevel.value(); +} + +void ExprSelect::bindVars(const StaticEnv& env) { + e->bindVars(env); + if (def != nullptr) { + def->bindVars(env); + } + for (auto& i : attrPath) { + if (auto* expr = std::get_if<Expr*>(&i)) { + (*expr)->bindVars(env); + } + } +} + +void ExprOpHasAttr::bindVars(const StaticEnv& env) { + e->bindVars(env); + for (auto& i : attrPath) { + if (auto* expr = std::get_if<Expr*>(&i)) { + (*expr)->bindVars(env); + } + } +} + +void ExprAttrs::bindVars(const StaticEnv& env) { + const StaticEnv* dynamicEnv = &env; + StaticEnv newEnv(/* isWith = */ false, &env); + + if (recursive) { + dynamicEnv = &newEnv; + + unsigned int displ = 0; + for (auto& i : attrs) { + newEnv.vars[i.first] = i.second.displ = displ++; + } + + for (auto& i : attrs) { + i.second.e->bindVars(i.second.inherited ? env : newEnv); + } + } + + else { + for (auto& i : attrs) { + i.second.e->bindVars(env); + } + } + + for (auto& i : dynamicAttrs) { + i.nameExpr->bindVars(*dynamicEnv); + i.valueExpr->bindVars(*dynamicEnv); + } +} + +void ExprList::bindVars(const StaticEnv& env) { + for (auto& i : elems) { + i->bindVars(env); + } +} + +void ExprLambda::bindVars(const StaticEnv& env) { + StaticEnv newEnv(false, &env); + + unsigned int displ = 0; + + if (!arg.empty()) { + newEnv.vars[arg] = displ++; + } + + if (matchAttrs) { + for (auto& i : formals->formals) { + newEnv.vars[i.name] = displ++; + } + + for (auto& i : formals->formals) { + if (i.def != nullptr) { + i.def->bindVars(newEnv); + } + } + } + + body->bindVars(newEnv); +} + +void ExprLet::bindVars(const StaticEnv& env) { + StaticEnv newEnv(false, &env); + + unsigned int displ = 0; + for (auto& i : attrs->attrs) { + newEnv.vars[i.first] = i.second.displ = displ++; + } + + for (auto& i : attrs->attrs) { + i.second.e->bindVars(i.second.inherited ? env : newEnv); + } + + body->bindVars(newEnv); +} + +void ExprWith::bindVars(const StaticEnv& 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; + unsigned int level; + prevWith = 0; + for (curEnv = &env, level = 1; curEnv != nullptr; + curEnv = curEnv->up, level++) { + if (curEnv->isWith) { + prevWith = level; + break; + } + } + + attrs->bindVars(env); + StaticEnv newEnv(true, &env); + body->bindVars(newEnv); +} + +void ExprIf::bindVars(const StaticEnv& env) { + cond->bindVars(env); + then->bindVars(env); + else_->bindVars(env); +} + +void ExprAssert::bindVars(const StaticEnv& env) { + cond->bindVars(env); + body->bindVars(env); +} + +void ExprOpNot::bindVars(const StaticEnv& env) { e->bindVars(env); } + +void ExprConcatStrings::bindVars(const StaticEnv& env) { + for (auto& i : *es) { + i->bindVars(env); + } +} + +void ExprPos::bindVars(const StaticEnv& env) {} + +/* Storing function names. */ +void ExprLambda::setName(Symbol& name) { this->name = name; } + +std::string ExprLambda::showNamePos() const { + return (format("%1% at %2%") % + (name.has_value() ? "'" + std::string(name.value()) + "'" + : "anonymous function") % + pos) + .str(); +} + +} // namespace nix |