diff options
Diffstat (limited to 'src/libexpr/nixexpr.cc')
| -rw-r--r-- | src/libexpr/nixexpr.cc | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc new file mode 100644 index 000000000..b2c9f0528 --- /dev/null +++ b/src/libexpr/nixexpr.cc @@ -0,0 +1,438 @@ +#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; +} + +static void showString(std::ostream & str, const string & s) +{ + str << '"'; + for (auto c : (string) s) + if (c == '"' || c == '\\' || c == '$') str << "\\" << c; + else if (c == '\n') str << "\\n"; + else if (c == '\r') str << "\\r"; + else if (c == '\t') str << "\\t"; + else str << c; + str << '"'; +} + +static void showId(std::ostream & str, const string & s) +{ + if (s.empty()) + str << "\"\""; + else if (s == "if") // FIXME: handle other keywords + str << '"' << s << '"'; + else { + char c = s[0]; + if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_')) { + showString(str, s); + return; + } + for (auto c : s) + if (!((c >= 'a' && c <= 'z') || + (c >= 'A' && c <= 'Z') || + (c >= '0' && c <= '9') || + c == '_' || c == '\'' || c == '-')) { + showString(str, s); + return; + } + str << s; + } +} + +std::ostream & operator << (std::ostream & str, const Symbol & sym) +{ + showId(str, *sym.s); + return str; +} + +void Expr::show(std::ostream & str) +{ + abort(); +} + +void ExprInt::show(std::ostream & str) +{ + str << n; +} + +void ExprFloat::show(std::ostream & str) +{ + str << nf; +} + +void ExprString::show(std::ostream & str) +{ + showString(str, s); +} + +void ExprPath::show(std::ostream & str) +{ + str << s; +} + +void ExprVar::show(std::ostream & str) +{ + str << name; +} + +void ExprSelect::show(std::ostream & str) +{ + str << "(" << *e << ")." << showAttrPath(attrPath); + if (def) str << " or (" << *def << ")"; +} + +void ExprOpHasAttr::show(std::ostream & str) +{ + str << "((" << *e << ") ? " << showAttrPath(attrPath) << ")"; +} + +void ExprAttrs::show(std::ostream & str) +{ + if (recursive) str << "rec "; + str << "{ "; + for (auto & i : attrs) + if (i.second.inherited) + str << "inherit " << i.first << " " << "; "; + else + str << i.first << " = " << *i.second.e << "; "; + for (auto & i : dynamicAttrs) + str << "\"${" << *i.nameExpr << "}\" = " << *i.valueExpr << "; "; + str << "}"; +} + +void ExprList::show(std::ostream & str) +{ + str << "[ "; + for (auto & i : elems) + str << "(" << *i << ") "; + str << "]"; +} + +void ExprLambda::show(std::ostream & str) +{ + str << "("; + if (matchAttrs) { + str << "{ "; + bool first = true; + for (auto & i : formals->formals) { + if (first) first = false; else str << ", "; + str << i.name; + if (i.def) 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) +{ + 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) +{ + 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; + str << "("; + for (auto & i : *es) { + if (first) first = false; else str << " + "; + str << *i; + } + str << ")"; +} + +void ExprPos::show(std::ostream & str) +{ + str << "__curPos"; +} + + +std::ostream & operator << (std::ostream & str, const Pos & pos) +{ + if (!pos) + str << "undefined position"; + else + str << (format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%") % (string) pos.file % pos.line % pos.column).str(); + return str; +} + + +string showAttrPath(const AttrPath & attrPath) +{ + std::ostringstream out; + bool first = true; + for (auto & i : attrPath) { + if (!first) out << '.'; else first = false; + if (i.symbol.set()) + out << i.symbol; + else + out << "\"${" << *i.expr << "}\""; + } + 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; + 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 UndefinedVarError(format("undefined variable ‘%1%’ at %2%") % name % pos); + + fromWith = true; + this->level = withLevel; +} + +void ExprSelect::bindVars(const StaticEnv & env) +{ + e->bindVars(env); + if (def) def->bindVars(env); + for (auto & i : attrPath) + if (!i.symbol.set()) + i.expr->bindVars(env); +} + +void ExprOpHasAttr::bindVars(const StaticEnv & env) +{ + e->bindVars(env); + for (auto & i : attrPath) + if (!i.symbol.set()) + i.expr->bindVars(env); +} + +void ExprAttrs::bindVars(const StaticEnv & env) +{ + const StaticEnv * dynamicEnv = &env; + StaticEnv newEnv(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) 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; 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 Expr::setName(Symbol & name) +{ +} + + +void ExprLambda::setName(Symbol & name) +{ + this->name = name; + body->setName(name); +} + + +string ExprLambda::showNamePos() const +{ + return (format("%1% at %2%") % (name.set() ? "‘" + (string) name + "’" : "anonymous function") % pos).str(); +} + + + +/* Symbol table. */ + +size_t SymbolTable::totalSize() const +{ + size_t n = 0; + for (auto & i : symbols) + n += i.size(); + return n; +} + + +} |