5.33.6 Quotes and braces

The distinction between braces ({ }) and quotes (" ") is significant when the list contains references to variables. When references are enclosed in quotes, they are substituted with values. However, when references are enclosed in braces, they are not substituted with values.

Example

With Braces

With Double Quotes

set b 2

set b 2

set t { 1 $b 3 }

set t " 1 $b 3 "

set s { [ expr $b + $b ] }

set s " [ expr $b + $b ] "

puts stdout $t

puts stdout $t

puts stdout $s

puts stdout $s