#include "nixexpr.hh" #include "derivations.hh" #include "util.hh" #include <cstdlib> namespace nix { /* Displaying abstract syntax trees. */ std::ostream & operator << (std::ostream & str, Expr & e) { e.show(str); return str; } void Expr::show(std::ostream & str) { abort(); } void ExprInt::show(std::ostream & str) { str << n; } void ExprString::show(std::ostream & str) { str << "\"" << s << "\""; // !!! escaping } void ExprPath::show(std::ostream & str) { str << s; } void ExprVar::show(std::ostream & str) { str << info.name; } void ExprSelect::show(std::ostream & str) { str << "(" << *e << ")." << showAttrPath(attrPath); if (def) str << " or " << *def; } void ExprOpHasAttr::show(std::ostream & str) { str << "(" << *e << ") ? " << showAttrPath(attrPath); } void ExprAttrs::show(std::ostream & str) { if (recursive) str << "rec "; str << "{ "; foreach (AttrDefs::iterator, i, attrs) if (i->second.inherited) str << "inherit " << i->first << " " << "; "; else str << i->first << " = " << *i->second.e << "; "; str << "}"; } void ExprList::show(std::ostream & str) { str << "[ "; foreach (vector<Expr *>::iterator, i, elems) str << "(" << **i << ") "; str << "]"; } void ExprLambda::show(std::ostream & str) { str << "("; if (matchAttrs) { str << "{ "; bool first = true; foreach (Formals::Formals_::iterator, i, formals->formals) { if (first) first = false; else str << ", "; str << i->name; if (i->def) str << " ? " << *i->def; } str << " }"; if (!arg.empty()) str << " @ "; } if (!arg.empty()) str << arg; str << ": " << *body << ")"; } void ExprLet::show(std::ostream & str) { str << "let "; foreach (ExprAttrs::AttrDefs::iterator, 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) { str << "with " << *attrs << "; " << *body; } void ExprIf::show(std::ostream & str) { str << "if " << *cond << " then " << *then << " else " << *else_; } void ExprAssert::show(std::ostream & str) { str << "assert " << *cond << "; " << *body; } void ExprOpNot::show(std::ostream & str) { str << "! " << *e; } void ExprConcatStrings::show(std::ostream & str) { bool first = true; foreach (vector<Expr *>::iterator, i, *es) { if (first) first = false; else str << " + "; str << **i; } } std::ostream & operator << (std::ostream & str, const Pos & pos) { if (!pos.line) str << "undefined position"; else str << (format("`%1%:%2%:%3%'") % pos.file % pos.line % pos.column).str(); return str; } string showAttrPath(const AttrPath & attrPath) { string s; foreach (AttrPath::const_iterator, i, attrPath) { if (!s.empty()) s += '.'; s += *i; } return s; } Pos noPos; /* Computing levels/displacements for variables. */ void Expr::bindVars(const StaticEnv & env) { abort(); } void ExprInt::bindVars(const StaticEnv & env) { } void ExprString::bindVars(const StaticEnv & env) { } void ExprPath::bindVars(const StaticEnv & env) { } void VarRef::bind(const StaticEnv & env) { /* Check whether the variable appears in the environment. If so, set its level and displacement. */ const StaticEnv * curEnv; unsigned int level; int withLevel = -1; for (curEnv = &env, level = 0; curEnv; curEnv = curEnv->up, level++) { if (curEnv->isWith) { if (withLevel == -1) withLevel = level; } else { StaticEnv::Vars::const_iterator 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 == -1) throw EvalError(format("undefined variable `%1%'") % name); fromWith = true; this->level = withLevel; } void ExprVar::bindVars(const StaticEnv & env) { info.bind(env); } void ExprSelect::bindVars(const StaticEnv & env) { e->bindVars(env); if (def) def->bindVars(env); } void ExprOpHasAttr::bindVars(const StaticEnv & env) { e->bindVars(env); } void ExprAttrs::bindVars(const StaticEnv & env) { if (recursive) { StaticEnv newEnv(false, &env); unsigned int displ = 0; foreach (AttrDefs::iterator, i, attrs) newEnv.vars[i->first] = i->second.displ = displ++; foreach (AttrDefs::iterator, i, attrs) if (i->second.inherited) i->second.var.bind(env); else i->second.e->bindVars(newEnv); } else foreach (AttrDefs::iterator, i, attrs) if (i->second.inherited) i->second.var.bind(env); else i->second.e->bindVars(env); } void ExprList::bindVars(const StaticEnv & env) { foreach (vector<Expr *>::iterator, 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) { foreach (Formals::Formals_::iterator, i, formals->formals) newEnv.vars[i->name] = displ++; foreach (Formals::Formals_::iterator, i, formals->formals) if (i->def) i->def->bindVars(newEnv); } body->bindVars(newEnv); } void ExprLet::bindVars(const StaticEnv & env) { StaticEnv newEnv(false, &env); unsigned int displ = 0; foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs) newEnv.vars[i->first] = i->second.displ = displ++; foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs) if (i->second.inherited) i->second.var.bind(env); else i->second.e->bindVars(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; 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) { foreach (vector<Expr *>::iterator, i, *es) (*i)->bindVars(env); } }