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* Assertions.

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* Logical operators (!, &&, ||, ->).
This commit is contained in:
Eelco Dolstra 2003-11-05 16:27:40 +00:00
parent e17e95a828
commit fa18f1f184
6 changed files with 77 additions and 16 deletions
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43
src/fix-ng/eval.cc
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@ -13,11 +13,6 @@ EvalState::EvalState()
}
Expr getAttr(EvalState & state, Expr e, const string & name)
{
}
/* Substitute an argument set into the body of a function. */
static Expr substArgs(Expr body, ATermList formals, Expr arg)
{
@ -142,7 +137,8 @@ Expr evalExpr2(EvalState & state, Expr e)
ATmatch(e, "Bool(<term>)", &e1) ||
ATmatch(e, "Function([<list>], <term>)", &e1, &e2) ||
ATmatch(e, "Attrs([<list>])", &e1) ||
ATmatch(e, "List([<list>])", &e1))
ATmatch(e, "List([<list>])", &e1) ||
ATmatch(e, "Null", &e1))
return e;
/* Any encountered variables must be undeclared or primops. */
@ -163,6 +159,8 @@ Expr evalExpr2(EvalState & state, Expr e)
if (primop == "derivation") return primDerivation(state, e2);
if (primop == "toString") return primToString(state, e2);
if (primop == "baseNameOf") return primBaseNameOf(state, e2);
if (primop == "null") return primNull(state, e2);
if (primop == "isNull") return primIsNull(state, e2);
else throw badTerm("undefined variable/primop", e1);
}
@ -200,13 +198,36 @@ Expr evalExpr2(EvalState & state, Expr e)
return evalExpr(state, e3);
}
/* Equality. Just strings for now. */
if (ATmatch(e, "OpEq(<term>, <term>)", &e1, &e2)) {
string s1 = evalString(state, e1);
string s2 = evalString(state, e2);
return s1 == s2 ? ATmake("Bool(True)") : ATmake("Bool(False)");
/* Assertions. */
if (ATmatch(e, "Assert(<term>, <term>)", &e1, &e2)) {
if (!evalBool(state, e1)) throw badTerm("guard failed", e);
return evalExpr(state, e2);
}
/* Generic equality. */
if (ATmatch(e, "OpEq(<term>, <term>)", &e1, &e2))
return makeBool(evalExpr(state, e1) == evalExpr(state, e2));
/* Generic inequality. */
if (ATmatch(e, "OpNEq(<term>, <term>)", &e1, &e2))
return makeBool(evalExpr(state, e1) != evalExpr(state, e2));
/* Negation. */
if (ATmatch(e, "OpNot(<term>)", &e1))
return makeBool(!evalBool(state, e1));
/* Implication. */
if (ATmatch(e, "OpImpl(<term>, <term>)", &e1, &e2))
return makeBool(!evalBool(state, e1) || evalBool(state, e2));
/* Conjunction (logical AND). */
if (ATmatch(e, "OpAnd(<term>, <term>)", &e1, &e2))
return makeBool(evalBool(state, e1) && evalBool(state, e2));
/* Disjunction (logical OR). */
if (ATmatch(e, "OpOr(<term>, <term>)", &e1, &e2))
return makeBool(evalBool(state, e1) || evalBool(state, e2));
/* Barf. */
throw badTerm("invalid expression", e);
}