Fossil

as an expression, and if that expression is true, evaluates its
second argument (the third token) as a TH1 script.
If the expression is false and the third argument is `else`, then
the fourth argument is evaluated as a TH1 expression.

So, you see, even though the example above spans five lines, it is really
just a single command.

All of this also explains the emphasis on *unescaped* characters above:
the curly braces `{ }` are string quoting characters in Tcl/TH1, not
block delimiters as in C. This is how we can have a command that extends
over multiple lines. It is also why the `else` keyword must be cuddled
up with the closing brace for the `if` clause's scriptlet. The following
is invalid Tcl/TH1:

        if {$current eq "dev"} {
          puts "hello"
        }
        else {
          puts "world"
        }

If you try to run this under either Tcl or TH1, the interpreter will
tell you that there is no `else` command, because with the newline on
the third line, you terminated the `if` command.

Occasionally in Tcl/TH1 scripts, you may need to use a backslash at the
end of a line to allow a command to extend over multiple lines without
being considered two separate commands. Here's an example from one of
Fossil's test scripts:

        return [lindex [regexp -line -inline -nocase -- \
            {^uuid:\s+([0-9A-F]{40}) } [eval [getFossilCommand \
            $repository "" info trunk]]] end]

Those backslashes allow the command to wrap nicely within a standard
terminal width while telling the interpreter to consider those three
lines as a single command.


Summary of Core TH1 Commands
----------------------------

The original Tcl language after when TH1 is modeled has a very rich
repertoire of commands.  TH1, as it is designed to be minimalist and
embedded has a greatly reduced command set.  The following bullets