Prolog Mode

Prolog mode applies automatically whenever you are editing a file that ends with the characters .pl. This mode is useful when you are editing Prolog source code. In Prolog mode:

• Whenever you type a closing parenthesis or bracket, the corresponding opening one is flashed. This bracket matching attempts to be clever about strings in quotes, because normally a bracket written within quotes should not count for matching purposes. Unfortunately, this means that the bracket matching does not work properly when radix notation (for example, 16'100 is hexadecimal 100, or 256 decimal) is used.
• The definition of <LFD> is modified. Immediately after a line with no leading space characters (normally the head of a clause), a <LFD> is equivalent to a <RET> followed by 8 spaces. ( This can be overridden by assigning the variable body-predicate-indent some other value.) Otherwise it is equivalent to a <RET> followed by enough tabs and spaces to put the cursor underneath the first non-space character in the previous line. A different set of rules apply for indentation within if-then-else constructs. Refer to quintus-directory/editor3.5/gnu/README for details. Note that the <TAB> key also indents the current line as prolog code. It differs from <LFD> in that a newline is not generated.