Hello world/Text: Difference between revisions

Since there is no string data type in the language, a symbol (an identifier or 'character atom') must be used instead. When writing a symbol in source code, exclamation mark is an escape character that allows characters such as spaces and exclamation marks to be treated as part of the symbol's name. Some output functions will include exclamation mark escapes when outputting such symbols, and others, such as <code>printc</code>, will not.

The single quote in front of <code>Hello! world!!</code> makes it an expression that evaluates to the symbol itself; otherwise, it would be treated as a variable and its value (if it had one) would be printed instead.