Simple Variable Substituion

[cptk]

${var}is the same as $var, and
${var_array(x,y)} is the same as $var_array(x,y), but ...

for $var_array($x,y) neither
${var_array($x,y)} nor ${var_array(${x},y)} works. How come?

 

[ulis]

You don't need to protect the name of a variable if its name contains only alphanumerics and underscores.
The parenthesis () are not part of the name but indicates the index of the element in the array.
It is perfectly legal to write:

$array($element)

and, as expected, to get the value of the element whose index is the value of the

element

variable in the array

array

.

Enclosing the parenthesis inside braces has for effect to avoid any evaluation of the string inside the braces (the string is taken as is).

${array($element)}

is the value of the variable whose name is

array($element)

. This name contains parenthesis and dollar sign and is very dangerous to use ;-)

Hopefully you can code:

foreach element {one two threee four} { lappend res $aray($element) }

HTH

ulis