是什么导致了这个 Ada 编译错误"ambiguous character literal"？

Question

我有这个Ada代码。

with Ada.Text_IO; 
use Ada.Text_IO;
procedure for_Loop is
begin
    for Counter in 'A'..'Z' loop
        Put(Counter);   
    end loop;
    New_Line;
end for_Loop;

Ada 编译器 （gnatmake） 输出这些错误消息。

gcc -c for_loop.adb
for_loop.adb:6:24: ambiguous character literal
for_loop.adb:6:24: possible interpretation: Character
for_loop.adb:6:24: possible interpretation: Wide_Character
for_loop.adb:6:24: possible interpretation: Wide_Wide_Character
gnatmake: "for_loop.adb" compilation error

代码有什么问题？

Answer 1

来自这篇文章：

问题是"A"和"Z"可能来自字符或Wide_Character。最简单的更正是使类型显式;例如：对于字符范围"A"中的字符.."Z"环...结束循环;

with Ada.Text_IO; 
use Ada.Text_IO;
procedure for_Loop is
begin
    for Counter in Character range 'A'..'Z' loop
        Put(Counter);   
    end loop;
    New_Line;
end for_Loop;

这是输出：

ABCDEFGHIJKLMNOPQRSTUVWXYZ