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#include "eval.hh"
#include "expr.hh"
#include "parser.hh"
EvalState::EvalState()
{
blackHole = ATmake("BlackHole()");
if (!blackHole) throw Error("cannot build black hole");
}
Expr evalExpr2(EvalState & state, Expr e)
{
return e;
}
Expr evalExpr(EvalState & state, Expr e)
{
Nest nest(lvlVomit, format("evaluating expression: %1%") % printTerm(e));
/* Consult the memo table to quickly get the normal form of
previously evaluated expressions. */
NormalForms::iterator i = state.normalForms.find(e);
if (i != state.normalForms.end()) {
if (i->second == state.blackHole)
throw badTerm("infinite recursion", e);
return i->second;
}
/* Otherwise, evaluate and memoize. */
state.normalForms[e] = state.blackHole;
Expr nf = evalExpr2(state, e);
state.normalForms[e] = nf;
return nf;
}
Expr evalFile(EvalState & state, const Path & path)
{
Nest nest(lvlTalkative, format("evaluating file `%1%'") % path);
Expr e = parseExprFromFile(path);
return evalExpr(state, e);
}
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