Basic Language Features
; or newline
Statement separator
\
Statement continuation if last character in line
#
Comment (null command)
var
Simple variable
var(index)
Associative array variable
var(i,j,...)
Multidimensional array variable
$var
Variable substitution (also ${
var
})- [
command
] Command substitution
- \
char
Backslash substitution (see "Backslash Substitutions,” later in this chapter)
- "
string
" Quoting with variable substitution
- {
string
} Quoting with no substitution (deferred substitution)
The only data type in Tcl is a string. However, some commands interpret arguments as numbers or boolean values. Here are some examples:
- Integer
123 0xff 0377
- Floating point
2.1 3. 6e4 7.91e+16
- Boolean
true false 0 1 yes no
Get Tcl/Tk in a Nutshell now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.