func prep(expr *ast.Expr, expType types.Type) (uniq string, err error) {
if expr.Function != nil {
fnc := expr.GetFunction()
uniq, err = WhichFunc(fnc)
if err != nil {
return "", err
}
typ, err := funcs.Out(uniq)
if err != nil {
return "", err
}
if typ != expType {
return "", &errExpected{expType.String(), expr.String()}
}
return uniq, err
}
if expr.List != nil {
if !types.IsList(expType) {
return "", &errExpected{expType.String(), expr.String()}
}
}
typ, err := Which(expr)
if err != nil {
return "", err
}
if typ != expType {
return "", &errExpected{expType.String(), expr.String()}
}
return "", nil
}
//Which returns the type that the expression will return.
func Which(expr *ast.Expr) (types.Type, error) {
if expr.Terminal != nil {
term := expr.GetTerminal()
if term.DoubleValue != nil {
return types.SINGLE_DOUBLE, nil
}
if term.IntValue != nil {
return types.SINGLE_INT, nil
}
if term.UintValue != nil {
return types.SINGLE_UINT, nil
}
if term.BoolValue != nil {
return types.SINGLE_BOOL, nil
}
if term.StringValue != nil {
return types.SINGLE_STRING, nil
}
if term.BytesValue != nil {
return types.SINGLE_BYTES, nil
}
if term.Variable != nil {
return term.Variable.Type, nil
}
}
if expr.List != nil {
return expr.GetList().GetType(), nil
}
if expr.Function != nil {
fnc := expr.GetFunction()
uniq, err := WhichFunc(fnc)
if err != nil {
return 0, err
}
return funcs.Out(uniq)
}
return 0, &errUnknownType{expr}
}