— Scheme Procedure: <group>-options [arg]
— Scheme Procedure: read-options [arg]
— Scheme Procedure: print-options [arg]
— Scheme Procedure: debug-options [arg]
— Scheme Procedure: traps [arg]

These functions list the options in their group. The optional argument arg is a symbol which modifies the form in which the options are presented.

With no arguments, <group>-options returns the values of the options in that particular group. If arg is 'help, a description of each option is given. If arg is 'full, programmers' options are also shown.

arg can also be a list representing the state of all options. In this case, the list contains single symbols (for enabled boolean options) and symbols followed by values.

— Scheme Procedure: <group>-enable option-symbol
— Scheme Procedure: read-enable option-symbol
— Scheme Procedure: print-enable option-symbol
— Scheme Procedure: debug-enable option-symbol
— Scheme Procedure: trap-enable option-symbol

These functions set the specified option-symbol in their options group. They only work if the option is boolean, and throw an error otherwise.

— Scheme Procedure: <group>-disable option-symbol
— Scheme Procedure: read-disable option-symbol
— Scheme Procedure: print-disable option-symbol
— Scheme Procedure: debug-disable option-symbol
— Scheme Procedure: trap-disable option-symbol

These functions turn off the specified option-symbol in their options group. They only work if the option is boolean, and throw an error otherwise.

— syntax: <group>-set! option-symbol value
— syntax: read-set! option-symbol value
— syntax: print-set! option-symbol value
— syntax: debug-set! option-symbol value
— syntax: trap-set! option-symbol value

These functions set a non-boolean option-symbol to the specified value.