21.1.7 Quotes and Braces
(Ask a Question)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.
The following table lists an example code.
| 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 |
The above example code will generate the following output:
1 $b 3 vs. 1 2 3
[ expr $b + $b ] 4