# The braced form of variable substitution handles more complex variable names:
set greeting "Hello, ${first name}"

# "set" can always be used instead of variable substitution, and can handle all
# variable names:
set greeting "Hello, [set {first name}]"


# To unpack a list into the command, use the expansion operator, "{*}".  These
# two commands are equivalent:
set name Neo
set {*}{name Neo}