[Martin Meyer]

Hi Thomas,

below code compiles in build 7402 but throws error c353 : Free parameter 'LocalType' is used in type expression in build 7500.

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interface refTerm{@Type}
    domains
        refTermValue =
            nil;
            atm(@Type Value);
            cmp(symbol FunctorName, refTerm{@Type}* ArgumentRtList);
            var(refTerm{@Type} Rt).
end interface refTerm
 
class refVar{@Type} : refTerm{@Type}
    predicates
        convertFromBaseType : (LocalType Value)
            -> refTerm{LocalType} RefTerm.
    constructors
        new : (refTermValue RtValue).
end class refVar
 
implement refVar{@Type}
    clauses
        convertFromBaseType(Val) = new(refVar{LocalType}::atm(Val)).
    clauses
        new(_).
end implement refVar

If the change is intended, please explain, for what reason it has been made, resp. what's wrong about the above construction.

Regards,
Martin

[Martin Meyer]

The parameter LocalType is unused in

Code: Select all

clauses
    convertFromBaseType(Val) = new(refVar{LocalType}::atm(Val)).

because it appears there only once. So I just tried replacing it by _. However on that the compiler issued error c504 : The expression has type 'refTerm::refTermValue{_}', which is incompatible with the type 'refTerm::refTermValue{LocalType}'.

Regards,
Martin

[Thomas Linder Puls]

That is unfortunately a bug, and will be investigated as such.

I assume the example is an extract of your real problem, and therefore this workaround may be too painful:

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interface refTerm{@Type}
    domains
        refTermValue{LocalType} =
            nil;
            atm(LocalType Value);
            cmp(symbol FunctorName, refTerm{LocalType}* ArgumentRtList);
            var(refTerm{LocalType} Rt).
    predicates
        p : (refTermValue{@Type}).
end interface refTerm
 
class refVar{@Type} : refTerm{@Type}
    predicates
        convertFromBaseType : (LocalType Value)
            -> refTerm{LocalType} RefTerm.
    constructors
        new : (refTermValue{@Type} RtValue).
end class refVar
 
implement refVar{@Type}
    clauses
        convertFromBaseType(Val) = new(refTerm{_}::atm(Val)).
    clauses
        new(_).
    clauses
        p(_).
end implement refVar

I.e. where refTermValue uses a local type parameter instead of the global one.

[Martin Meyer]

I just found out, that the compiler error disappears, when replacing in my code

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        convertFromBaseType(Val) = new(refVar{LocalType}::atm(Val)).

by

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        convertFromBaseType(Val) = new(refVar::atm(Val)).

or even better by

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        convertFromBaseType(Val) = new(refTerm::atm(Val)).

Thanx Thomas for supporting me!
Martin

[Martin Meyer]

Maybe it stems from same issue, that the compiler build 7500 throws fatal error c098 : getTypeVariableTerm name(03822B00,"atm","Atm",false) on this code. Can you provide a fix for the issue?

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interface refTerm{@Atom}
 
    constants
        fct_cons : symbol = "cons".
 
    domains
        refTermValue =
            nil;
            atm(@Atom Value);
            cmp(symbol FunctorName, refTerm{@Atom}* ArgumentRtList);
            var(refTerm{@Atom} Rt).
 
    properties
        value : refTermValue (o).
 
    predicates
        tryToValueList : (refTermValue RtValueTail [out])
            -> refTermValue* RtValueFront
            determ.
 
end interface refTerm
 
% ---
 
class refTerm{@Atom} : refTerm{@Atom}
end class refTerm
 
% ---
 
implement refTerm{@Atom}
 
    facts
        value : refTermValue := nil.
 
    clauses
        tryToValueList(RtValTail) = tryToValueList_0(value, RtValTail).
 
    class predicates
        tryToValueList_0 : (
            refTerm{Atm}::refTermValue RtValue,
            refTerm{Atm}::refTermValue RtValueTail [out])
            -> refTerm{Atm}::refTermValue* RtValueFront
            determ.
    clauses
        tryToValueList_0(refTerm::cmp(refTerm::fct_cons, [HeadRt, RestFrontRt]), RtValTail) =
            [HeadRt:value | RestFrontRt:tryToValueList(RtValTail)].
        tryToValueList_0(refTerm::nil, refTerm::nil) = [].
        tryToValueList_0(refTerm::var(FreeRt), refTerm::var(FreeRt)) = [].
 
end implement refTerm

Regards,
Martin

[Thomas Linder Puls]

This is more or less the same bug.

And you can solve the problem in the same way as advised above:

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interface refTerm{@Atom}
 
    constants
        fct_cons : symbol = "cons".
 
    domains
        refTermValue{Atm} =
            nil;
            atm(Atm Value);
            cmp(symbol FunctorName, refTerm{Atm}* ArgumentRtList);
            var(refTerm{Atm} Rt).
 
    properties
        value : refTermValue{@Atom} (o).
 
    predicates
        tryToValueList : (refTermValue{@Atom} RtValueTail [out])
            -> refTermValue{@Atom}* RtValueFront
            determ.
 
end interface refTerm
 
% ---
 
class refTerm{@Atom} : refTerm{@Atom}
end class refTerm
 
% ---
 
implement refTerm{@Atom}
 
    facts
        value : refTermValue{@Atom} := nil.
 
    clauses
        tryToValueList(RtValTail) = tryToValueList_0(value, RtValTail).
 
    class predicates
        tryToValueList_0 : (
            refTermValue{Atm} RtValue,
            refTermValue{Atm} RtValueTail [out])
            -> refTermValue{Atm}* RtValueFront
            determ.
    clauses
            tryToValueList_0(refTerm::cmp(refTerm::fct_cons, [HeadRt, RestFrontRt]), RtValTail) =
                [HeadRt:value | RestFrontRt:tryToValueList(RtValTail)].
            tryToValueList_0(refTerm::nil, refTerm::nil) = [].
            tryToValueList_0(refTerm::var(FreeRt), refTerm::var(FreeRt)) = [].
 
end implement refTerm

[Martin Meyer]

To my supprise I found, that the below compiles. I.e. it does NOT cause something like error c530 : The object member 'refTerm{@Atom}::@Atom/0' is used in the class predicate 'refTerm{@Atom}::tryToValueList_0/2->'.

Is it unintended? Or, does the compiler in class predicate tryToValueList_0/2-> cleverly capture the value of @Atom, which is used in domain refTermValue, from context, and that refTermValue does not need to be qualified by refTerm{Atm}::, is syntactic sugar?

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interface refTerm{@Atom}
 
    constants
        fct_cons : symbol = "cons".
 
    domains
        refTermValue =
            nil;
            atm(@Atom Value);
            cmp(symbol FunctorName, refTerm{@Atom}* ArgumentRtList);
            var(refTerm{@Atom} Rt).
 
    properties
        value : refTermValue (o).
 
    predicates
        tryToValueList : (refTermValue RtValueTail [out])
            -> refTermValue* RtValueFront
            determ.
 
end interface refTerm
 
% ---
 
class refTerm{@Atom} : refTerm{@Atom}
end class refTerm
 
% ---
 
implement refTerm{@Atom}
 
    facts
        value : refTermValue := nil.
 
    clauses
        tryToValueList(RtValTail) = tryToValueList_0(value, RtValTail).
 
    class predicates
        tryToValueList_0 : (
            refTermValue RtValue,
            refTermValue RtValueTail [out])
            -> refTermValue* RtValueFront
            determ.
    clauses
            tryToValueList_0(cmp(fct_cons, [HeadRt, RestFrontRt]), RtValTail) =
                [HeadRt:value | RestFrontRt:tryToValueList(RtValTail)].
            tryToValueList_0(nil, nil) = [].
            tryToValueList_0(var(FreeRt), var(FreeRt)) = [].
 
end implement refTerm

Regards
Martin

[Thomas Linder Puls]

No, that is not intended. Your first code is correct, the second one accidentally works.