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Diffstat (limited to 'src/libexpr/nixexpr.hh')
-rw-r--r-- | src/libexpr/nixexpr.hh | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh new file mode 100644 index 000000000000..d2ca09b3a5bb --- /dev/null +++ b/src/libexpr/nixexpr.hh @@ -0,0 +1,343 @@ +#pragma once + +#include "value.hh" +#include "symbol-table.hh" + +#include <map> + + +namespace nix { + + +MakeError(EvalError, Error) +MakeError(ParseError, Error) +MakeError(IncompleteParseError, ParseError) +MakeError(AssertionError, EvalError) +MakeError(ThrownError, AssertionError) +MakeError(Abort, EvalError) +MakeError(TypeError, EvalError) +MakeError(UndefinedVarError, Error) +MakeError(RestrictedPathError, Error) + + +/* Position objects. */ + +struct Pos +{ + Symbol file; + unsigned int line, column; + Pos() : line(0), column(0) { }; + Pos(const Symbol & file, unsigned int line, unsigned int column) + : file(file), line(line), column(column) { }; + operator bool() const + { + return line != 0; + } + bool operator < (const Pos & p2) const + { + if (!line) return p2.line; + if (!p2.line) return false; + int d = ((string) file).compare((string) p2.file); + if (d < 0) return true; + if (d > 0) return false; + if (line < p2.line) return true; + if (line > p2.line) return false; + return column < p2.column; + } +}; + +extern Pos noPos; + +std::ostream & operator << (std::ostream & str, const Pos & pos); + + +struct Env; +struct Value; +class EvalState; +struct StaticEnv; + + +/* An attribute path is a sequence of attribute names. */ +struct AttrName +{ + Symbol symbol; + Expr * expr; + AttrName(const Symbol & s) : symbol(s) {}; + AttrName(Expr * e) : expr(e) {}; +}; + +typedef std::vector<AttrName> AttrPath; + +string showAttrPath(const AttrPath & attrPath); + + +/* Abstract syntax of Nix expressions. */ + +struct Expr +{ + virtual ~Expr() { }; + virtual void show(std::ostream & str); + virtual void bindVars(const StaticEnv & env); + virtual void eval(EvalState & state, Env & env, Value & v); + virtual Value * maybeThunk(EvalState & state, Env & env); + virtual void setName(Symbol & name); +}; + +std::ostream & operator << (std::ostream & str, Expr & e); + +#define COMMON_METHODS \ + void show(std::ostream & str); \ + void eval(EvalState & state, Env & env, Value & v); \ + void bindVars(const StaticEnv & env); + +struct ExprInt : Expr +{ + NixInt n; + Value v; + ExprInt(NixInt n) : n(n) { mkInt(v, n); }; + COMMON_METHODS + Value * maybeThunk(EvalState & state, Env & env); +}; + +struct ExprFloat : Expr +{ + NixFloat nf; + Value v; + ExprFloat(NixFloat nf) : nf(nf) { mkFloat(v, nf); }; + COMMON_METHODS + Value * maybeThunk(EvalState & state, Env & env); +}; + +struct ExprString : Expr +{ + Symbol s; + Value v; + ExprString(const Symbol & s) : s(s) { mkString(v, s); }; + COMMON_METHODS + Value * maybeThunk(EvalState & state, Env & env); +}; + +/* Temporary class used during parsing of indented strings. */ +struct ExprIndStr : Expr +{ + string s; + ExprIndStr(const string & s) : s(s) { }; +}; + +struct ExprPath : Expr +{ + string s; + Value v; + ExprPath(const string & s) : s(s) { mkPathNoCopy(v, this->s.c_str()); }; + COMMON_METHODS + Value * maybeThunk(EvalState & state, Env & env); +}; + +struct ExprVar : Expr +{ + Pos pos; + Symbol name; + + /* Whether the variable comes from an environment (e.g. a rec, let + or function argument) or from a "with". */ + bool fromWith; + + /* In the former case, the value is obtained by going `level' + levels up from the current environment and getting the + `displ'th value in that environment. In the latter case, the + value is obtained by getting the attribute named `name' from + the set stored in the environment that is `level' levels up + from the current one.*/ + unsigned int level; + unsigned int displ; + + ExprVar(const Symbol & name) : name(name) { }; + ExprVar(const Pos & pos, const Symbol & name) : pos(pos), name(name) { }; + COMMON_METHODS + Value * maybeThunk(EvalState & state, Env & env); +}; + +struct ExprSelect : Expr +{ + Pos pos; + Expr * e, * def; + AttrPath attrPath; + ExprSelect(const Pos & pos, Expr * e, const AttrPath & attrPath, Expr * def) : pos(pos), e(e), def(def), attrPath(attrPath) { }; + ExprSelect(const Pos & pos, Expr * e, const Symbol & name) : pos(pos), e(e), def(0) { attrPath.push_back(AttrName(name)); }; + COMMON_METHODS +}; + +struct ExprOpHasAttr : Expr +{ + Expr * e; + AttrPath attrPath; + ExprOpHasAttr(Expr * e, const AttrPath & attrPath) : e(e), attrPath(attrPath) { }; + COMMON_METHODS +}; + +struct ExprAttrs : Expr +{ + bool recursive; + struct AttrDef { + bool inherited; + Expr * e; + Pos pos; + unsigned int displ; // displacement + AttrDef(Expr * e, const Pos & pos, bool inherited=false) + : inherited(inherited), e(e), pos(pos) { }; + AttrDef() { }; + }; + typedef std::map<Symbol, AttrDef> AttrDefs; + AttrDefs attrs; + struct DynamicAttrDef { + Expr * nameExpr, * valueExpr; + Pos pos; + DynamicAttrDef(Expr * nameExpr, Expr * valueExpr, const Pos & pos) + : nameExpr(nameExpr), valueExpr(valueExpr), pos(pos) { }; + }; + typedef std::vector<DynamicAttrDef> DynamicAttrDefs; + DynamicAttrDefs dynamicAttrs; + ExprAttrs() : recursive(false) { }; + COMMON_METHODS +}; + +struct ExprList : Expr +{ + std::vector<Expr *> elems; + ExprList() { }; + COMMON_METHODS +}; + +struct Formal +{ + Symbol name; + Expr * def; + Formal(const Symbol & name, Expr * def) : name(name), def(def) { }; +}; + +struct Formals +{ + typedef std::list<Formal> Formals_; + Formals_ formals; + std::set<Symbol> argNames; // used during parsing + bool ellipsis; +}; + +struct ExprLambda : Expr +{ + Pos pos; + Symbol name; + Symbol arg; + bool matchAttrs; + Formals * formals; + Expr * body; + ExprLambda(const Pos & pos, const Symbol & arg, bool matchAttrs, Formals * formals, Expr * body) + : pos(pos), arg(arg), matchAttrs(matchAttrs), formals(formals), body(body) + { + if (!arg.empty() && formals && formals->argNames.find(arg) != formals->argNames.end()) + throw ParseError(format("duplicate formal function argument ‘%1%’ at %2%") + % arg % pos); + }; + void setName(Symbol & name); + string showNamePos() const; + COMMON_METHODS +}; + +struct ExprLet : Expr +{ + ExprAttrs * attrs; + Expr * body; + ExprLet(ExprAttrs * attrs, Expr * body) : attrs(attrs), body(body) { }; + COMMON_METHODS +}; + +struct ExprWith : Expr +{ + Pos pos; + Expr * attrs, * body; + unsigned int prevWith; + ExprWith(const Pos & pos, Expr * attrs, Expr * body) : pos(pos), attrs(attrs), body(body) { }; + COMMON_METHODS +}; + +struct ExprIf : Expr +{ + Expr * cond, * then, * else_; + ExprIf(Expr * cond, Expr * then, Expr * else_) : cond(cond), then(then), else_(else_) { }; + COMMON_METHODS +}; + +struct ExprAssert : Expr +{ + Pos pos; + Expr * cond, * body; + ExprAssert(const Pos & pos, Expr * cond, Expr * body) : pos(pos), cond(cond), body(body) { }; + COMMON_METHODS +}; + +struct ExprOpNot : Expr +{ + Expr * e; + ExprOpNot(Expr * e) : e(e) { }; + COMMON_METHODS +}; + +#define MakeBinOp(name, s) \ + struct Expr##name : Expr \ + { \ + Pos pos; \ + Expr * e1, * e2; \ + Expr##name(Expr * e1, Expr * e2) : e1(e1), e2(e2) { }; \ + Expr##name(const Pos & pos, Expr * e1, Expr * e2) : pos(pos), e1(e1), e2(e2) { }; \ + void show(std::ostream & str) \ + { \ + str << "(" << *e1 << " " s " " << *e2 << ")"; \ + } \ + void bindVars(const StaticEnv & env) \ + { \ + e1->bindVars(env); e2->bindVars(env); \ + } \ + void eval(EvalState & state, Env & env, Value & v); \ + }; + +MakeBinOp(App, "") +MakeBinOp(OpEq, "==") +MakeBinOp(OpNEq, "!=") +MakeBinOp(OpAnd, "&&") +MakeBinOp(OpOr, "||") +MakeBinOp(OpImpl, "->") +MakeBinOp(OpUpdate, "//") +MakeBinOp(OpConcatLists, "++") + +struct ExprConcatStrings : Expr +{ + Pos pos; + bool forceString; + vector<Expr *> * es; + ExprConcatStrings(const Pos & pos, bool forceString, vector<Expr *> * es) + : pos(pos), forceString(forceString), es(es) { }; + COMMON_METHODS +}; + +struct ExprPos : Expr +{ + Pos pos; + ExprPos(const Pos & pos) : pos(pos) { }; + COMMON_METHODS +}; + + +/* Static environments are used to map variable names onto (level, + displacement) pairs used to obtain the value of the variable at + runtime. */ +struct StaticEnv +{ + bool isWith; + const StaticEnv * up; + typedef std::map<Symbol, unsigned int> Vars; + Vars vars; + StaticEnv(bool isWith, const StaticEnv * up) : isWith(isWith), up(up) { }; +}; + + +} |