Tcl 8.4：扩展用作过程参数的变量

如何解决Tcl 8.4：扩展用作过程参数的变量

我在 Tcl 8.4 中遇到问题。

我想做的事情的概念是这样的：

• 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），因此可以像 builtinFn {arg_1a arg_1b} "two" "three" "four" 一样调用它，说；
• 我想提供一个包装函数 wrapperFn，它检查第一个参数，然后将其分解成其组成部分（上面示例中的 arg_1a 和 arg_1b），然后分别使用第一个参数的每个单独组成部分调用 builtinFn，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 Error: wrong # args: 中调用 builtinFn 时，都会收到一条错误消息“wrapperFn”。

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：无论您在哪里看到 mess，请把它读成类似于 puts — 它只是以一种简洁的方式写入控制台，并可以选择指定文本的颜色。

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).  

我看到了一些可能具有某种相关性的帖子。

• 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（例如 list 或 concat 或 eval）来实现它。

我尝试过的其他一些不起作用的东西：

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   (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 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   (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 1).  

如果不明显，我需要由 myInternal 编写的第二个语句（从 myWrapper 调用），以完全匹配第一个语句，由myWrapper“直接”写入。

感谢您的建议！

——DIV

解决方法

正如您所收集的，在 Tcl 8.4 中，您需要为此使用 eval。为了合理地确保不会发生副作用，您需要将一个列表传递给 eval，该列表由命令的名称和每个单独的参数组成。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，或者让事情变得更糟。

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

,

根据 Schelte Bron 的回答，wrapperFn 将是

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