Tcl 8.4：扩展用作过程参数的变量

Question

我在 Tcl 8.4 中遇到问题。

我想做的事情的概念是这样的：

一个现有的内置函数，builtinFn，有一个必需的参数，然后是可变数量的参数（实际需要的数量取决于第一个参数），所以它可以像 builtinFn {arg_1a arg_1b} "two" "three" "four", 说;
我想提供一个包装函数 wrapperFn，它检查第一个参数，然后将其分解为其组成部分（上例中的 arg_1a 和 arg_1b），然后分别调用 builtinFn 第一个参数的每个单独成分，如 builtinFn {arg_1a} "two" "three" "four" 和 builtinFn {arg_1b} "two" "three" "four".

无论我尝试过什么，当我从 wrapperFn.

中调用 builtinFn 时，我都会收到错误消息“Error: wrong # args:”

问题的简化示例

proc myInternal {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" turquoise4;
}
proc myWrapper {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
myInternal $var1 $args
}

注意：无论你在哪里看到 mess，请将其理解为类似于 puts — 它只是以一种简洁的方式写入控制台，并带有指定颜色的选项正文。

如果我调用myInternal one two three，那么输出是

var1 is one (length is 1), and args is two three  (length is 2).

如果我调用myWrapper one two three，那么输出是

var1 is one (length is 1), and args is two three  (length is 2).  
var1 is one (length is 1), and args is {two three}  (length is 1).

我看到了一些可能相关的帖子。

TCL- How to interpret a string as multiple arguments in tcl procedures? [duplicate]
TCL script: variable as argument of a function

也许这可以用 Tcl 8.5 中的 {*} 解决，但我目前无法使用。我还没有想出如何使用任何其他选项来实现它，例如 list 或 concat 或 eval.

我尝试过的其他一些方法无效：

proc myWrapper2 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
myInternal "$var1 $args"
}
myWrapper2 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one two three (length is 3), and args is   (length is 0).  

proc myWrapper3 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
myInternal $var1 [split $args]
}
myWrapper3 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one (length is 1), and args is {two three}  (length is 1).  

proc myWrapper4a {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
myInternal [list $var1 $args]
}
myWrapper4a one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one {two three} (length is 2), and args is   (length is 0).  

proc myWrapper4b {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
myInternal [concat $var1 $args]
}
myWrapper4b one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one two three (length is 3), and args is   (length is 0).  

proc myWrapper5 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
myInternal [puts "$var1 $args"]
}
myWrapper5 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is  (length is 0), and args is   (length is 0).  

proc myWrapper6 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
eval myInternal $var1 [split $args ,]
}
myWrapper6 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one (length is 1), and args is {two three}  (length is 1).  

proc myWrapper7 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
eval myInternal [split "$var1 $args" ,]
}
myWrapper7 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one two three (length is 3), and args is   (length is 0).  

proc myWrapper8 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
eval {myInternal [split "$var1 $args" ,]}
}
myWrapper8 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is {one two three} (length is 1), and args is   (length is 0).  

proc myWrapper9 {var1 args} { 
mess "var1 is $var1 (length is [llength $var1]), and args is $args  (length is [llength $args]).  \n" green4; 
eval [linsert {} 0 myInternal $var1 $args]
}
myWrapper9 one two three
# Output:  
# var1 is one (length is 1), and args is two three  (length is 2).  
# var1 is one (length is 1), and args is {two three}  (length is 1).

如果不是很明显，我需要第二个语句，它由 myInternal（从 myWrapper 调用）写成 exactly匹配第一个语句，由 myWrapper.

写成 'directly'

感谢任何提示！

—DIV

Answer 1

如您所知，在 Tcl 8.4 中您需要为此使用 eval。为了确保没有副作用发生，您需要将一个列表传递给 eval，其中包含命令名称，后跟每个单独的参数。为您的示例实现此目的的一种方法是：

eval [linsert $args 0 myInternal $var1]

在您的所有尝试中，您一直将 args 作为单个元素传递，或者使事情变得更糟。

使用 concat 的方法可以是：

eval [concat myInternal [list $var1] $args]

请注意，您必须在 $var1 周围使用 list 以防止它可能包含的任何特殊字符造成破坏。例如：

myWrapper "hello world" two three
myWrapper \{ two three

Answer 2

根据 Schelte Bron 的回答，wrapperFn 将是

proc wrapperFn {varlist args} {
    foreach var $varlist {
        eval [linsert $args 0 builtinFn $var]
    }
}

Tcl 8.4：扩展用作过程参数的变量

Tcl 8.4: expanding variables used as arguments to procedures

function

variables

tcl

procedure

expand