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* Every real language has a `map' function.

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This commit is contained in:
Eelco Dolstra 2004-08-04 11:27:53 +00:00
parent bbfdd64741
commit d8989b1fb4
2 changed files with 19 additions and 2 deletions
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2
src/libexpr/eval.cc
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@ -221,7 +221,7 @@ Expr evalExpr2(EvalState & state, Expr e)
(state, args2); (state, args2);
} else } else
/* Need more arguments, so propagate the primop. */ /* Need more arguments, so propagate the primop. */
return ATmake("PrimOp(<int>, <term>, <list>)", return ATmake("PrimOp(<int>, <term>, <term>)",
arity, fun, args); arity, fun, args);
} }

19
src/libexpr/primops.cc
View file

@ -314,8 +314,23 @@ Expr primIsNull(EvalState & state, const ATermVector & args)
/* Apply a function to every element of a list. */ /* Apply a function to every element of a list. */
Expr primMap(EvalState & state, Expr fun, Expr list) Expr primMap(EvalState & state, const ATermVector & args)
{ {
Expr fun = evalExpr(state, args[0]);
Expr list = evalExpr(state, args[1]);
ATMatcher m;
ATermList list2;
if (!(atMatch(m, list) >> "List" >> list2))
throw Error("`map' expects a list as its second argument");
ATermList list3 = ATempty;
for (ATermIterator i(list2); i; ++i)
list3 = ATinsert(list3,
ATmake("Call(<term>, <term>)", fun, *i));
return ATmake("List(<term>)", ATreverse(list3));
} }
@ -330,4 +345,6 @@ void EvalState::addPrimOps()
addPrimOp("baseNameOf", 1, primBaseNameOf); addPrimOp("baseNameOf", 1, primBaseNameOf);
addPrimOp("toString", 1, primToString); addPrimOp("toString", 1, primToString);
addPrimOp("isNull", 1, primIsNull); addPrimOp("isNull", 1, primIsNull);
addPrimOp("map", 2, primMap);
} }