forked from lix-project/lix
18a48d80a0
Functions in Nix are anonymous, but if they're assigned to a variable/attribute, we can use the variable/attribute name in error messages, e.g. while evaluating `concatMapStrings' at `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/strings.nix:18:25': ...
348 lines
7.4 KiB
C++
348 lines
7.4 KiB
C++
#include "nixexpr.hh"
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#include "derivations.hh"
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#include "util.hh"
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#include <cstdlib>
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namespace nix {
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/* Displaying abstract syntax trees. */
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std::ostream & operator << (std::ostream & str, Expr & e)
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{
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e.show(str);
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return str;
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}
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void Expr::show(std::ostream & str)
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{
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abort();
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}
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void ExprInt::show(std::ostream & str)
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{
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str << n;
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}
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void ExprString::show(std::ostream & str)
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{
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str << "\"" << s << "\""; // !!! escaping
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}
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void ExprPath::show(std::ostream & str)
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{
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str << s;
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}
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void ExprVar::show(std::ostream & str)
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{
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str << info.name;
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}
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void ExprSelect::show(std::ostream & str)
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{
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str << "(" << *e << ")." << showAttrPath(attrPath);
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if (def) str << " or " << *def;
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}
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void ExprOpHasAttr::show(std::ostream & str)
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{
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str << "(" << *e << ") ? " << showAttrPath(attrPath);
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}
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void ExprAttrs::show(std::ostream & str)
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{
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if (recursive) str << "rec ";
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str << "{ ";
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited)
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str << "inherit " << i->first << " " << "; ";
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else
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str << i->first << " = " << *i->second.e << "; ";
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str << "}";
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}
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void ExprList::show(std::ostream & str)
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{
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str << "[ ";
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foreach (vector<Expr *>::iterator, i, elems)
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str << "(" << **i << ") ";
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str << "]";
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}
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void ExprLambda::show(std::ostream & str)
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{
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str << "(";
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if (matchAttrs) {
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str << "{ ";
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bool first = true;
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foreach (Formals::Formals_::iterator, i, formals->formals) {
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if (first) first = false; else str << ", ";
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str << i->name;
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if (i->def) str << " ? " << *i->def;
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}
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str << " }";
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if (!arg.empty()) str << " @ ";
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}
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if (!arg.empty()) str << arg;
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str << ": " << *body << ")";
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}
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void ExprLet::show(std::ostream & str)
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{
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str << "let ";
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foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs)
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if (i->second.inherited)
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str << "inherit " << i->first << "; ";
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else
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str << i->first << " = " << *i->second.e << "; ";
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str << "in " << *body;
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}
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void ExprWith::show(std::ostream & str)
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{
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str << "with " << *attrs << "; " << *body;
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}
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void ExprIf::show(std::ostream & str)
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{
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str << "if " << *cond << " then " << *then << " else " << *else_;
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}
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void ExprAssert::show(std::ostream & str)
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{
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str << "assert " << *cond << "; " << *body;
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}
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void ExprOpNot::show(std::ostream & str)
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{
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str << "! " << *e;
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}
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void ExprConcatStrings::show(std::ostream & str)
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{
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bool first = true;
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foreach (vector<Expr *>::iterator, i, *es) {
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if (first) first = false; else str << " + ";
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str << **i;
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}
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}
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std::ostream & operator << (std::ostream & str, const Pos & pos)
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{
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if (!pos.line)
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str << "undefined position";
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else
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str << (format("`%1%:%2%:%3%'") % pos.file % pos.line % pos.column).str();
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return str;
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}
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string showAttrPath(const AttrPath & attrPath)
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{
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string s;
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foreach (AttrPath::const_iterator, i, attrPath) {
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if (!s.empty()) s += '.';
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s += *i;
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}
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return s;
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}
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Pos noPos;
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/* Computing levels/displacements for variables. */
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void Expr::bindVars(const StaticEnv & env)
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{
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abort();
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}
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void ExprInt::bindVars(const StaticEnv & env)
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{
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}
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void ExprString::bindVars(const StaticEnv & env)
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{
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}
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void ExprPath::bindVars(const StaticEnv & env)
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{
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}
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void VarRef::bind(const StaticEnv & env)
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{
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/* Check whether the variable appears in the environment. If so,
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set its level and displacement. */
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const StaticEnv * curEnv;
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unsigned int level;
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int withLevel = -1;
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for (curEnv = &env, level = 0; curEnv; curEnv = curEnv->up, level++) {
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if (curEnv->isWith) {
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if (withLevel == -1) withLevel = level;
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} else {
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StaticEnv::Vars::const_iterator i = curEnv->vars.find(name);
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if (i != curEnv->vars.end()) {
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fromWith = false;
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this->level = level;
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displ = i->second;
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return;
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}
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}
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}
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/* Otherwise, the variable must be obtained from the nearest
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enclosing `with'. If there is no `with', then we can issue an
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"undefined variable" error now. */
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if (withLevel == -1) throw EvalError(format("undefined variable `%1%'") % name);
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fromWith = true;
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this->level = withLevel;
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}
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void ExprVar::bindVars(const StaticEnv & env)
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{
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info.bind(env);
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}
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void ExprSelect::bindVars(const StaticEnv & env)
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{
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e->bindVars(env);
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if (def) def->bindVars(env);
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}
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void ExprOpHasAttr::bindVars(const StaticEnv & env)
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{
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e->bindVars(env);
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}
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void ExprAttrs::bindVars(const StaticEnv & env)
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{
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if (recursive) {
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StaticEnv newEnv(false, &env);
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unsigned int displ = 0;
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foreach (AttrDefs::iterator, i, attrs)
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newEnv.vars[i->first] = i->second.displ = displ++;
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited) i->second.var.bind(env);
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else i->second.e->bindVars(newEnv);
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}
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else
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foreach (AttrDefs::iterator, i, attrs)
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if (i->second.inherited) i->second.var.bind(env);
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else i->second.e->bindVars(env);
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}
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void ExprList::bindVars(const StaticEnv & env)
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{
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foreach (vector<Expr *>::iterator, i, elems)
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(*i)->bindVars(env);
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}
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void ExprLambda::bindVars(const StaticEnv & env)
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{
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StaticEnv newEnv(false, &env);
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unsigned int displ = 0;
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if (!arg.empty()) newEnv.vars[arg] = displ++;
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if (matchAttrs) {
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foreach (Formals::Formals_::iterator, i, formals->formals)
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newEnv.vars[i->name] = displ++;
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foreach (Formals::Formals_::iterator, i, formals->formals)
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if (i->def) i->def->bindVars(newEnv);
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}
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body->bindVars(newEnv);
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}
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void ExprLet::bindVars(const StaticEnv & env)
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{
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StaticEnv newEnv(false, &env);
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unsigned int displ = 0;
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foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs)
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newEnv.vars[i->first] = i->second.displ = displ++;
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foreach (ExprAttrs::AttrDefs::iterator, i, attrs->attrs)
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if (i->second.inherited) i->second.var.bind(env);
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else i->second.e->bindVars(newEnv);
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body->bindVars(newEnv);
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}
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void ExprWith::bindVars(const StaticEnv & env)
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{
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/* Does this `with' have an enclosing `with'? If so, record its
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level so that `lookupVar' can look up variables in the previous
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`with' if this one doesn't contain the desired attribute. */
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const StaticEnv * curEnv;
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unsigned int level;
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prevWith = 0;
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for (curEnv = &env, level = 1; curEnv; curEnv = curEnv->up, level++)
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if (curEnv->isWith) {
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prevWith = level;
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break;
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}
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attrs->bindVars(env);
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StaticEnv newEnv(true, &env);
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body->bindVars(newEnv);
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}
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void ExprIf::bindVars(const StaticEnv & env)
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{
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cond->bindVars(env);
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then->bindVars(env);
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else_->bindVars(env);
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}
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void ExprAssert::bindVars(const StaticEnv & env)
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{
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cond->bindVars(env);
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body->bindVars(env);
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}
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void ExprOpNot::bindVars(const StaticEnv & env)
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{
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e->bindVars(env);
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}
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void ExprConcatStrings::bindVars(const StaticEnv & env)
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{
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foreach (vector<Expr *>::iterator, i, *es)
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(*i)->bindVars(env);
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}
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/* Storing function names. */
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void Expr::setName(Symbol & name)
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{
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}
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void ExprLambda::setName(Symbol & name)
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{
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this->name = name;
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body->setName(name);
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}
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string ExprLambda::showNamePos()
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{
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return (format("%1% at %2%") % (name.set() ? "`" + (string) name + "'" : "an anonymous function") % pos).str();
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}
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}
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