Features

Some things are missing, e.g. variable references, but they are emulated as nullary function calls.

So while in TCL you would write

set foo 42
puts $foo

in micker, you only call foo:

set foo 42
puts [foo]

This means there is only one namespace, namely for commands.

Another difference is that if a function call results in a list, which is spliced into some execution context, it will appear as several words, not a word with spaces. If you want it the latter way, you have to put double quotes around the call:

set bar "foo 42"
set [bar]
puts [foo]
puts "[bar]"

The parser is very simple. It only has two modes, in-string and out-string. A double-quote enters the in-string mode, but when an opening bracket is encountered we enter out-string mode again. This way there is no ugly escaping all the time. Escapes (\) are only needed to hinder the parser changing modes. The {...} construct suppresses certain mode transitions, but deals with escapes.

Some examples:

puts "a double quote: \""
puts "amount [total] contains [expr [total] * .2] VAT"
puts "the words used to be [list "one" [word-two] and "three"]"

[Note that the third line is colored incorrectly!]

Another in-string mode is called script. In a script no embedded commands get evaluated:

puts {a script-like string with unevaluated [command]}

I Wish Micker Had That...

To keep the implementation straightforward, many things you take for granted in TCL are not present in micker:

micker is a Lisp-1, that is, there are no separate namespaces for commands and variables,
micker is dynamically scoped, that is, there are no local variables, only globals.

This means, there are a lot of problems you can run into, and keep in mind that "set" is a very dangerous command, as it can redefine built-in commands easily where you possibly only mean to initialize a local variable.

Future

Micker shall be extended with new features as the need arises, given time.

Present

Most of the ideas above are actually implemented. But expect bugs.