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#ifndef __NIXEXPR_H
#define __NIXEXPR_H
#include <map>
#include "symbol-table.hh"
namespace nix {
MakeError(EvalError, Error)
MakeError(ParseError, Error)
MakeError(AssertionError, EvalError)
MakeError(ThrownError, AssertionError)
MakeError(Abort, EvalError)
MakeError(TypeError, EvalError)
/* Position objects. */
struct Pos
{
string file;
unsigned int line, column;
};
std::ostream & operator << (std::ostream & str, const Pos & pos);
struct Env;
struct Value;
struct EvalState;
struct StaticEnv;
/* Abstract syntax of Nix expressions. */
struct Expr
{
virtual void show(std::ostream & str);
virtual void bindVars(const StaticEnv & env);
virtual void eval(EvalState & state, Env & env, Value & v);
};
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
{
int n;
ExprInt(int n) : n(n) { };
COMMON_METHODS
};
struct ExprString : Expr
{
string s;
ExprString(const string & s) : s(s) { };
COMMON_METHODS
};
/* Temporary class used during parsing of indented strings. */
struct ExprIndStr : Expr
{
string s;
ExprIndStr(const string & s) : s(s) { };
};
struct ExprPath : Expr
{
string s;
ExprPath(const string & s) : s(s) { };
COMMON_METHODS
};
struct ExprVar : Expr
{
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 attribute 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) { };
COMMON_METHODS
};
struct ExprSelect : Expr
{
Expr * e;
Symbol name;
ExprSelect(Expr * e, const Symbol & name) : e(e), name(name) { };
COMMON_METHODS
};
struct ExprOpHasAttr : Expr
{
Expr * e;
Symbol name;
ExprOpHasAttr(Expr * e, const Symbol & name) : e(e), name(name) { };
COMMON_METHODS
};
struct ExprAttrs : Expr
{
bool recursive;
typedef std::map<Symbol, Expr *> Attrs;
Attrs attrs;
list<Symbol> inherited;
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;
bool ellipsis;
};
struct ExprLambda : Expr
{
Pos pos;
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) { };
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;
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 \
{ \
Expr * e1, * e2; \
Expr##name(Expr * e1, Expr * e2) : 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
{
vector<Expr *> * es;
ExprConcatStrings(vector<Expr *> * es) : es(es) { };
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) { };
};
}
#endif /* !__NIXEXPR_H */
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