我使用输出
运行以下代码Erlang R16B (erts-5.10.1) [smp:8:8] [async-threads:10]
Eshell V5.10.1 (abort with ^G)
1> rr(record_io).
[memory]
2> record_io:store(99).
stored: 2
ok
3> record_io:print().
stored: 2
ok
4>
我想知道的是如何将值正确存储到记录中，显然record_io:print().的输出应该是99而不是2。这是代码。
-module(record_io).
-export([store/1, print/0]).
-record(memory, {value}).
store(Value) ->
#memory{ value = Value},
io:format("stored: ~p~n",[#memory.value]).
print() ->
io:format("stored: ~p~n",[#memory.value]).
我尝试了另一种方式，但也没有用。
4> c(record_io).
record_io.erl:6: Warning: a term is constructed, but never used
{ok,record_io}
5> rr(record_io).
[memory]
6> record_io:store(S,10).
* 1: variable 'S' is unbound
7>
修改后的record_io的代码。
-module(record_io).
-export([store/2, print/1]).
-record(memory, {value}).
store(S,Value) ->
S#memory{ value = Value},
io:format("stored: ~p~n",[S#memory.value]),
S.
print(S) ->
io:format("stored: ~p~n",[S#memory.value]).
编辑：解决方案。
代码
-module(record_io).
-export([store/1, print/1]).
-record(memory, {value}).
store(Value) ->
Rec2 = #memory{ value = Value},
io:format("stored: ~p~n",[Rec2#memory.value]),
Rec2.
print(S) ->
io:format("stored: ~p~n",[S#memory.value]).
命令行。
Rec = record_io:store(99).
record_io:print(Rec).
stored: 99
{memory,99}
stored: 99
ok