Data types
Vocabulary: push means "place on the top of the stack" and pull means "remove from the top of the stack".
All values have a type characterising their properties.
Arguably the most important type in the language. A list is an ordered sequence of zero or more values (that can be other lists). Values contained in a list do not need to be of the same type (i.e. lists can be heterogenous).
A list begin with [ and end with ]. All values located between these delimiters are the contents of the list. Values do not need to be separated by commas as it is the case in many languages.
[][42 hello][1 2 3][ [3.14] foo ]
The list is pushed without being itself executed.
A symbol is a named value. It is mainly used as an identifier to reference a value defined in a different part of a program.
A symbol can begin with any letter (A to Z, a to z) or one of the following characters: ~!@#$%^&*_+-=|\;,.<>?/, followed by zero or more characters of the same set extended with digits (0 to 9). The sequence -- forms the beginning of a comment, thus a symbol cannot use it.
foo+Hello-World
Look for a reserved value or a defined operation. Push a copy of the value or execute the operation, respectively. If nothing is found, raise an error.
A quoted symbol is similar to a symbol but with different semantics.
A quoted symbol begins with : followed by a symbol.
:foo:+:Hello-World
Push the quoted symbol.
A boolean is either true or false. There isn't any special syntax for booleans: They are created with the operations TRUE and FALSE.
Push the boolean.
A number represents… well, a number. There is no distinction between integers and floats: They are just numbers.
423.14-1
Push the number.
A character is signaled by ' followed by the character to represent. Whitespace characters space, tabulation and new-line are represented with \s, \t and \n, respectively. The \ character is represented with \\.
'a'1\n
Push the number.
A string is not actually a type: It's just a list containing only characters. As a shortcut, a string can be represented with the delimiters ". The " character inside a string is represented with """.
-
"abc"(equivalent to['a 'b 'c]) "hello world""\"Nono\""