Compiler errors Eiffel:在或和中的本地声明未能编译
编译器正在抱怨未知标识符,似乎它无法识别我的多个声明中的任何一个,我错在哪里Compiler errors Eiffel:在或和中的本地声明未能编译,compiler-errors,eiffel,Compiler Errors,Eiffel,编译器正在抱怨未知标识符,似乎它无法识别我的多个声明中的任何一个,我错在哪里 if attached {INTEGER_REF} field.item as l_int or attached {INTEGER_64} field.item as l_int or ( attached {TUPLE} field.item as l_tuple and then attached {INTEGER_64} l_tuple.item (1) as l_int ) t
if attached {INTEGER_REF} field.item as l_int
or attached {INTEGER_64} field.item as l_int
or ( attached {TUPLE} field.item as l_tuple and then attached {INTEGER_64} l_tuple.item (1) as l_int ) then
Result.put_integer (l_int.to_integer_64, primary_key_db_column_name)
elseif attached {STRING} field.item as l_s then
Result.put_string (l_s, primary_key_db_column_name)
end
更新
由于这似乎是一个有效的表达式,我认为如果在我的或的每个分支中都声明了l_int
,那么我应该能够在范围中使用它
但是这个表达式似乎是有效的
if attached a.b as l_b and then attached l_b.c as l_c then
l_c.is_available_in_this_scope
l_b.is_available_in_this_scope
else
io.putstring ("you are wrong dear and either l_b and l_c are not available!")
end
而这个不是强>
if attached a.b as l_b and then attached l_b.c as l_c
or attached a.x as l_b and then attached l_x.d as l_c then
l_c.is_available_in_this_scope -- Compiler complain about l_c
l_b.is_available_in_this_scope -- Compiler complain about l_b
else
io.putstring ("you are wrong dear and either l_b and l_c are not available!")
end
用我的代码
此编译
if attached {INTEGER_REF} field.item as l_int then
Result.put_integer (l_int.to_integer_64, primary_key_db_column_name)
elseif attached {INTEGER_64} field.item as l_int then
Result.put_integer (l_int, primary_key_db_column_name)
elseif attached {TUPLE} field.item as l_tuple and then attached {INTEGER_64} l_tuple.item (1) as l_int then
Result.put_integer (l_int, primary_key_db_column_name)
elseif attached {STRING} field.item as l_s then
Result.put_string (l_s, primary_key_db_column_name)
else
logger.write_error ("to_json-> Type not found in matching:" + field.item.out)
check
not_found_item_type: False
end
end
而这个不是
if attached {INTEGER_REF} field.item as l_int then
Result.put_integer (l_int.to_integer_64, primary_key_db_column_name)
elseif attached {INTEGER_64} field.item as l_int
or attached {TUPLE} field.item as l_tuple and then attached {INTEGER_64} l_tuple.item (1) as l_int then
Result.put_integer (l_int, primary_key_db_column_name) -- Unknown identifier `l_int`
elseif attached {STRING} field.item as l_s then
Result.put_string (l_s, primary_key_db_column_name)
else
logger.write_error ("to_json-> Type not found in matching:" + field.item.out)
check
not_found_item_type: False
end
end
首先,对于同一范围内的多个对象测试局部变量,不能使用相同的标识符(l_int)。对象测试有作用域。用
OT
表示对象测试,其范围为
if OT then A else B end
if OT and ... then A else B end
if OT or ... then C else B end
只是A
。因此,对于析取,作用域为空,并且不能在任何分支中使用相应的对象测试局部
如果条件测试中有两个对象测试,则它们的范围可能重叠或不重叠:
if OT1 and OT2 then A else B end
if OT1 and then OT2 then A else B end
if OT1 or OT2 then C else B end
这里,与前面一样,OT1
的对象测试局部变量具有范围a
。此外,对于和,范围包括OT2
,尤其是OT2
可以使用OT1
的本地。出于同样的原因,OT2
不能使用OT1
的同一对象本地测试
对于析取,对象测试局部变量OT1
和OT2
的作用域都是空的。为了提供更多信息,具有助记名称的相同代码如下所示:
if attached e1 as x and attached e2_without_x as y then use_x_and_y else B end
if attached e1 as x and then attached e2_with_x as y then use_x_and_y else B end
if attached e1 as x or attached e2_without_x as y then no_x_no_y else B end
如果所有涉及的表达式的类型都相同,则仍然可以用一个第一分支重写示例(事实并非如此,因为存在类型INTEGER\u 64
和INTEGER\u REF
):
但是这变得太麻烦了,使用多个分支或临时局部变量看起来是更好的选择。Thx,但这就是我没有做的吗?你的建议对我有何影响?请参阅我对亚历山大的编辑和问题,以获得更精确的答案,谢谢!很多thx,这对我很有帮助,但我对我的问题做了编辑,因为在这种情况下我仍然有疑问。。。编译器在这里抱怨是因为l_int
可以是整数REF和整数64吗?@Pipo这是因为对于析取,对象测试局部变量的作用域是空的。并且,每个对象测试都是单独考虑的,即两个对象测试局部不能视为一个。因此,对于析取,您有两个空作用域,并且不能使用任何一个变量。对不起,即使阅读您大约10次,我仍然没有抓住要点:-(你看到我的编辑了吗?如果你有动机,也许你可以给你的答案添加一个编辑!@Pipo没有规则将两个对象测试中的对象测试局部变量组合成一个变量。此外,如果对象测试用于析取,则对象测试局部变量的作用域为空。我用更多的测试更新了答案。)这次得到了!!!由于或
和INTEGER\u 64/INTEGER\u REF使它不可用,这不是因为编译限制,而是我的错误Maaaany thx!!
if attached
if attached {INTEGER_64_REF} field.item as i then
i
elseif
attached {TUPLE} field.item as t and then
t.count > 0 and then
attached {INTEGER_64_REF} t.item (1) as i
then
i
else
Void
end
as j
then
-- Use j
...