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