19ad871b74
Progress towards REUSE compliance. Change-Id: Ia64efc4fbf4e8eb3800b75159f357ea009438ae1 Signed-off-by: Raito Bezarius <raito@lix.systems>
512 lines
16 KiB
C++
512 lines
16 KiB
C++
// SPDX-FileCopyrightText: 2024 Nix and Lix Authors
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//
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// SPDX-License-Identifier: LGPL-2.1-only
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#pragma once
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///@file
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#include <map>
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#include <vector>
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#include "value.hh"
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#include "symbol-table.hh"
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#include "error.hh"
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#include "position.hh"
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#include "eval-error.hh"
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#include "pos-idx.hh"
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#include "pos-table.hh"
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namespace nix {
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struct Env;
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struct Value;
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class EvalState;
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struct ExprWith;
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struct StaticEnv;
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/**
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* An attribute path is a sequence of attribute names.
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*/
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struct AttrName
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{
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Symbol symbol;
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std::unique_ptr<Expr> expr;
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AttrName(Symbol s) : symbol(s) {};
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AttrName(std::unique_ptr<Expr> e) : expr(std::move(e)) {};
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};
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typedef std::vector<AttrName> AttrPath;
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std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath);
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/* Abstract syntax of Nix expressions. */
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struct Expr
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{
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protected:
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Expr(Expr &&) = default;
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Expr & operator=(Expr &&) = default;
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public:
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struct AstSymbols {
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Symbol sub, lessThan, mul, div, or_, findFile, nixPath, body;
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};
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Expr() = default;
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Expr(const Expr &) = delete;
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Expr & operator=(const Expr &) = delete;
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virtual ~Expr() { };
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virtual void show(const SymbolTable & symbols, std::ostream & str) const;
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virtual void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env);
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virtual void eval(EvalState & state, Env & env, Value & v);
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virtual Value * maybeThunk(EvalState & state, Env & env);
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virtual void setName(Symbol name);
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virtual PosIdx getPos() const { return noPos; }
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};
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#define COMMON_METHODS \
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void show(const SymbolTable & symbols, std::ostream & str) const override; \
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void eval(EvalState & state, Env & env, Value & v) override; \
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void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env) override;
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struct ExprInt : Expr
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{
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NixInt n;
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Value v;
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ExprInt(NixInt n) : n(n) { v.mkInt(n); };
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Value * maybeThunk(EvalState & state, Env & env) override;
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COMMON_METHODS
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};
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struct ExprFloat : Expr
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{
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NixFloat nf;
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Value v;
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ExprFloat(NixFloat nf) : nf(nf) { v.mkFloat(nf); };
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Value * maybeThunk(EvalState & state, Env & env) override;
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COMMON_METHODS
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};
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struct ExprString : Expr
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{
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std::string s;
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Value v;
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ExprString(std::string &&s) : s(std::move(s)) { v.mkString(this->s.data()); };
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Value * maybeThunk(EvalState & state, Env & env) override;
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COMMON_METHODS
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};
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struct ExprPath : Expr
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{
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std::string s;
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Value v;
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ExprPath(std::string s) : s(std::move(s)) { v.mkPath(this->s.c_str()); };
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Value * maybeThunk(EvalState & state, Env & env) override;
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COMMON_METHODS
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};
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typedef uint32_t Level;
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typedef uint32_t Displacement;
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struct ExprVar : Expr
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{
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PosIdx pos;
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Symbol name;
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/* Whether the variable comes from an environment (e.g. a rec, let
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or function argument) or from a "with".
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`nullptr`: Not from a `with`.
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Valid pointer: the nearest, innermost `with` expression to query first. */
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ExprWith * fromWith;
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/* In the former case, the value is obtained by going `level`
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levels up from the current environment and getting the
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`displ`th value in that environment. In the latter case, the
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value is obtained by getting the attribute named `name` from
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the set stored in the environment that is `level` levels up
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from the current one.*/
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Level level;
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Displacement displ;
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ExprVar(Symbol name) : name(name) { };
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ExprVar(const PosIdx & pos, Symbol name) : pos(pos), name(name) { };
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Value * maybeThunk(EvalState & state, Env & env) override;
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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/**
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* A pseudo-expression for the purpose of evaluating the `from` expression in `inherit (from)` syntax.
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* Unlike normal variable references, the displacement is set during parsing, and always refers to
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* `ExprAttrs::inheritFromExprs` (by itself or in `ExprLet`), whose values are put into their own `Env`.
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*/
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struct ExprInheritFrom : ExprVar
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{
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ref<Expr> fromExpr;
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ExprInheritFrom(PosIdx pos, Displacement displ, ref<Expr> fromExpr)
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: ExprVar(pos, {}), fromExpr(fromExpr)
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{
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this->level = 0;
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this->displ = displ;
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this->fromWith = nullptr;
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}
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void show(SymbolTable const & symbols, std::ostream & str) const override;
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void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env) override;
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};
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struct ExprSelect : Expr
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{
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PosIdx pos;
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/** The expression attributes are being selected on. e.g. `foo` in `foo.bar.baz`. */
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std::unique_ptr<Expr> e;
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/** A default value specified with `or`, if the selected attr doesn't exist.
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* e.g. `bix` in `foo.bar.baz or bix`
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*/
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std::unique_ptr<Expr> def;
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/** The path of attributes being selected. e.g. `bar.baz` in `foo.bar.baz.` */
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AttrPath attrPath;
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ExprSelect(const PosIdx & pos, std::unique_ptr<Expr> e, AttrPath attrPath, std::unique_ptr<Expr> def) : pos(pos), e(std::move(e)), def(std::move(def)), attrPath(std::move(attrPath)) { };
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ExprSelect(const PosIdx & pos, std::unique_ptr<Expr> e, Symbol name) : pos(pos), e(std::move(e)) { attrPath.push_back(AttrName(name)); };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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struct ExprOpHasAttr : Expr
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{
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std::unique_ptr<Expr> e;
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AttrPath attrPath;
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ExprOpHasAttr(std::unique_ptr<Expr> e, AttrPath attrPath) : e(std::move(e)), attrPath(std::move(attrPath)) { };
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PosIdx getPos() const override { return e->getPos(); }
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COMMON_METHODS
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};
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struct ExprAttrs : Expr
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{
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bool recursive;
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PosIdx pos;
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struct AttrDef {
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enum class Kind {
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/** `attr = expr;` */
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Plain,
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/** `inherit attr1 attrn;` */
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Inherited,
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/** `inherit (expr) attr1 attrn;` */
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InheritedFrom,
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};
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Kind kind;
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std::unique_ptr<Expr> e;
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PosIdx pos;
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Displacement displ; // displacement
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AttrDef(std::unique_ptr<Expr> e, const PosIdx & pos, Kind kind = Kind::Plain)
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: kind(kind), e(std::move(e)), pos(pos) { };
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AttrDef() { };
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template<typename T>
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const T & chooseByKind(const T & plain, const T & inherited, const T & inheritedFrom) const
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{
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switch (kind) {
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case Kind::Plain:
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return plain;
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case Kind::Inherited:
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return inherited;
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default:
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case Kind::InheritedFrom:
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return inheritedFrom;
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}
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}
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};
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typedef std::map<Symbol, AttrDef> AttrDefs;
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AttrDefs attrs;
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std::unique_ptr<std::vector<ref<Expr>>> inheritFromExprs;
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struct DynamicAttrDef {
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std::unique_ptr<Expr> nameExpr, valueExpr;
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PosIdx pos;
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DynamicAttrDef(std::unique_ptr<Expr> nameExpr, std::unique_ptr<Expr> valueExpr, const PosIdx & pos)
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: nameExpr(std::move(nameExpr)), valueExpr(std::move(valueExpr)), pos(pos) { };
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};
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typedef std::vector<DynamicAttrDef> DynamicAttrDefs;
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DynamicAttrDefs dynamicAttrs;
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ExprAttrs(const PosIdx &pos) : recursive(false), pos(pos) { };
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ExprAttrs() : recursive(false) { };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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std::shared_ptr<const StaticEnv> bindInheritSources(
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EvalState & es, const std::shared_ptr<const StaticEnv> & env);
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Env * buildInheritFromEnv(EvalState & state, Env & up);
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void showBindings(const SymbolTable & symbols, std::ostream & str) const;
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};
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struct ExprList : Expr
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{
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std::vector<std::unique_ptr<Expr>> elems;
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ExprList() { };
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COMMON_METHODS
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Value * maybeThunk(EvalState & state, Env & env) override;
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PosIdx getPos() const override
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{
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return elems.empty() ? noPos : elems.front()->getPos();
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}
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};
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struct Formal
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{
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PosIdx pos;
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Symbol name;
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std::unique_ptr<Expr> def;
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};
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/** Attribute set destructuring in arguments of a lambda, if present */
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struct Formals
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{
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typedef std::vector<Formal> Formals_;
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Formals_ formals;
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bool ellipsis;
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bool has(Symbol arg) const
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{
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auto it = std::lower_bound(formals.begin(), formals.end(), arg,
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[] (const Formal & f, const Symbol & sym) { return f.name < sym; });
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return it != formals.end() && it->name == arg;
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}
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std::vector<std::reference_wrapper<const Formal>> lexicographicOrder(const SymbolTable & symbols) const
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{
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std::vector<std::reference_wrapper<const Formal>> result(formals.begin(), formals.end());
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std::sort(result.begin(), result.end(),
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[&] (const Formal & a, const Formal & b) {
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std::string_view sa = symbols[a.name], sb = symbols[b.name];
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return sa < sb;
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});
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return result;
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}
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};
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struct ExprLambda : Expr
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{
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/** Where the lambda is defined in Nix code. May be falsey if the
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* position is not known. */
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PosIdx pos;
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/** Name of the lambda. This is set if the lambda is defined in a
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* let-expression or an attribute set, such that there is a name.
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* Lambdas may have a falsey symbol as the name if they are anonymous */
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Symbol name;
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/** The argument name of this particular lambda. Is a falsey symbol if there
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* is no such argument. */
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Symbol arg;
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/** Formals are present when the lambda destructures an attr set as
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* argument, with or without ellipsis */
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std::unique_ptr<Formals> formals;
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std::unique_ptr<Expr> body;
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ExprLambda(PosIdx pos, Symbol arg, std::unique_ptr<Formals> formals, std::unique_ptr<Expr> body)
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: pos(pos), arg(arg), formals(std::move(formals)), body(std::move(body))
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{
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};
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ExprLambda(PosIdx pos, std::unique_ptr<Formals> formals, std::unique_ptr<Expr> body)
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: pos(pos), formals(std::move(formals)), body(std::move(body))
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{
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}
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void setName(Symbol name) override;
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std::string showNamePos(const EvalState & state) const;
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inline bool hasFormals() const { return formals != nullptr; }
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PosIdx getPos() const override { return pos; }
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/** Returns the name of the lambda,
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* or "anonymous lambda" if it doesn't have one.
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*/
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inline std::string getName(SymbolTable const & symbols) const
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{
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if (this->name) {
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return symbols[this->name];
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}
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return "anonymous lambda";
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}
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/** Returns the name of the lambda in single quotes,
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* or "anonymous lambda" if it doesn't have one.
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*/
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inline std::string getQuotedName(SymbolTable const & symbols) const
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{
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if (this->name) {
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return concatStrings("'", symbols[this->name], "'");
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}
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return "anonymous lambda";
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}
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COMMON_METHODS
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};
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struct ExprCall : Expr
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{
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std::unique_ptr<Expr> fun;
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std::vector<std::unique_ptr<Expr>> args;
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PosIdx pos;
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ExprCall(const PosIdx & pos, std::unique_ptr<Expr> fun, std::vector<std::unique_ptr<Expr>> && args)
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: fun(std::move(fun)), args(std::move(args)), pos(pos)
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{ }
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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struct ExprLet : Expr
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{
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std::unique_ptr<ExprAttrs> attrs;
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std::unique_ptr<Expr> body;
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ExprLet(std::unique_ptr<ExprAttrs> attrs, std::unique_ptr<Expr> body) : attrs(std::move(attrs)), body(std::move(body)) { };
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COMMON_METHODS
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};
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struct ExprWith : Expr
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{
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PosIdx pos;
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std::unique_ptr<Expr> attrs, body;
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size_t prevWith;
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ExprWith * parentWith;
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ExprWith(const PosIdx & pos, std::unique_ptr<Expr> attrs, std::unique_ptr<Expr> body) : pos(pos), attrs(std::move(attrs)), body(std::move(body)) { };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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struct ExprIf : Expr
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{
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PosIdx pos;
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std::unique_ptr<Expr> cond, then, else_;
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ExprIf(const PosIdx & pos, std::unique_ptr<Expr> cond, std::unique_ptr<Expr> then, std::unique_ptr<Expr> else_) : pos(pos), cond(std::move(cond)), then(std::move(then)), else_(std::move(else_)) { };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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struct ExprAssert : Expr
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{
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PosIdx pos;
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std::unique_ptr<Expr> cond, body;
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ExprAssert(const PosIdx & pos, std::unique_ptr<Expr> cond, std::unique_ptr<Expr> body) : pos(pos), cond(std::move(cond)), body(std::move(body)) { };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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struct ExprOpNot : Expr
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{
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std::unique_ptr<Expr> e;
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ExprOpNot(std::unique_ptr<Expr> e) : e(std::move(e)) { };
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PosIdx getPos() const override { return e->getPos(); }
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COMMON_METHODS
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};
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#define MakeBinOp(name, s) \
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struct name : Expr \
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{ \
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PosIdx pos; \
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std::unique_ptr<Expr> e1, e2; \
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name(std::unique_ptr<Expr> e1, std::unique_ptr<Expr> e2) : e1(std::move(e1)), e2(std::move(e2)) { }; \
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name(const PosIdx & pos, std::unique_ptr<Expr> e1, std::unique_ptr<Expr> e2) : pos(pos), e1(std::move(e1)), e2(std::move(e2)) { }; \
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void show(const SymbolTable & symbols, std::ostream & str) const override \
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{ \
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str << "("; e1->show(symbols, str); str << " " s " "; e2->show(symbols, str); str << ")"; \
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} \
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void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env) override \
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{ \
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e1->bindVars(es, env); e2->bindVars(es, env); \
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} \
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void eval(EvalState & state, Env & env, Value & v) override; \
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PosIdx getPos() const override { return pos; } \
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};
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MakeBinOp(ExprOpEq, "==")
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MakeBinOp(ExprOpNEq, "!=")
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MakeBinOp(ExprOpAnd, "&&")
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MakeBinOp(ExprOpOr, "||")
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MakeBinOp(ExprOpImpl, "->")
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MakeBinOp(ExprOpUpdate, "//")
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MakeBinOp(ExprOpConcatLists, "++")
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struct ExprConcatStrings : Expr
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{
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PosIdx pos;
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bool forceString;
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std::vector<std::pair<PosIdx, std::unique_ptr<Expr>>> es;
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ExprConcatStrings(const PosIdx & pos, bool forceString, std::vector<std::pair<PosIdx, std::unique_ptr<Expr>>> es)
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: pos(pos), forceString(forceString), es(std::move(es)) { };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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struct ExprPos : Expr
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{
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PosIdx pos;
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ExprPos(const PosIdx & pos) : pos(pos) { };
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PosIdx getPos() const override { return pos; }
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COMMON_METHODS
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};
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/* only used to mark thunks as black holes. */
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struct ExprBlackHole : Expr
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{
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void show(const SymbolTable & symbols, std::ostream & str) const override {}
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void eval(EvalState & state, Env & env, Value & v) override;
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void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env) override {}
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};
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extern ExprBlackHole eBlackHole;
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/* Static environments are used to map variable names onto (level,
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displacement) pairs used to obtain the value of the variable at
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runtime. */
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struct StaticEnv
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{
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ExprWith * isWith;
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const StaticEnv * up;
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// Note: these must be in sorted order.
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typedef std::vector<std::pair<Symbol, Displacement>> Vars;
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Vars vars;
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StaticEnv(ExprWith * isWith, const StaticEnv * up, size_t expectedSize = 0) : isWith(isWith), up(up) {
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vars.reserve(expectedSize);
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};
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void sort()
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{
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std::stable_sort(vars.begin(), vars.end(),
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[](const Vars::value_type & a, const Vars::value_type & b) { return a.first < b.first; });
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}
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void deduplicate()
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{
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auto it = vars.begin(), jt = it, end = vars.end();
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while (jt != end) {
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*it = *jt++;
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while (jt != end && it->first == jt->first) *it = *jt++;
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it++;
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}
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vars.erase(it, end);
|
|
}
|
|
|
|
Vars::const_iterator find(Symbol name) const
|
|
{
|
|
Vars::value_type key(name, 0);
|
|
auto i = std::lower_bound(vars.begin(), vars.end(), key);
|
|
if (i != vars.end() && i->first == name) return i;
|
|
return vars.end();
|
|
}
|
|
};
|
|
|
|
|
|
}
|