[英]deparse expressions containing `:=`?
Expressions containing :=
don't deparse
nicely : 表达式包含:=
不要很好地deparse
:
call1 <- quote(f(a = b(c = d)))
call2 <- quote(f(a := b(c := d)))
# nice
deparse(call1)
#> [1] "f(a = b(c = d))"
# not nice
deparse(call2)
# [1] "f(`:=`(a, b(`:=`(c, d))))"
I would like to get the following output from call2
: "f(a := b(c := d))"
. 我想从call2
得到以下输出: "f(a := b(c := d))"
。
I'm looking for a general solution that deparses :=
just like =
or <-
in all situations. 我正在寻找一个解决方案:=
=
在所有情况下都是=
或<-
。
A workaround 解决方法
This workaround uses the fact that <<-
has similar or same precedence and is not often used. 此解决方法使用<<-
具有相似或相同的优先级并且不经常使用的事实。 I substitute :=
by <<-
in the original call, then it deparses nicely, and I gsub
it back to :=
. 我代替:=
由<<-
在原来的呼叫,然后deparses很好,我gsub
回:=
。 I would like a clean and general solution though. 我想要一个干净而通用的解决方案。
gsub("<<-",":=", deparse(do.call(
substitute, list(call2, list(`:=` = quote(`<<-`))))))
#> [1] "f(a := b(c := d))"
You can achieve your desired result using rlang::expr_deparse()
which offers some printing improvements. 您可以使用rlang::expr_deparse()
来实现您想要的结果,它提供了一些打印改进。
rlang::expr_deparse(call2)
[1] "f(a := b(c := d))"
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