 -- Class: <gtk-spin-button>
     Derives from <gtk-entry>.

     This class defines the following slots:

     adjustment
          The adjustment that holds the value of the spinbutton

     climb-rate
          The acceleration rate when you hold down a button

     digits
          The number of decimal places to display

     snap-to-ticks
          Whether erroneous values are automatically changed to a spin button's nearest step increment

     numeric
          Whether non-numeric characters should be ignored

     wrap
          Whether a spin button should wrap upon reaching its limits

     update-policy
          Whether the spin button should update always, or only when the value is legal

     value
          Reads the current value, or sets a new value

 -- Signal on <gtk-spin-button>: value-changed

 -- Signal on <gtk-spin-button>: change-value (arg0 <gtk-scroll-type>)

 -- Signal on <gtk-spin-button>: input (arg0 <gpointer>) => <gint>

 -- Signal on <gtk-spin-button>: output => <gboolean>

 -- Signal on <gtk-spin-button>: wrapped
     The wrapped signal is emitted right after the spinbutton wraps from its maximum to minimum value or vice-versa.

     Since 2.10

 -- Function: gtk-spin-button-configure (self <gtk-spin-button>) (adjustment <gtk-adjustment>) (climb_rate double) (digits unsigned-int)
 -- Method: configure
     Changes the properties of an existing spin button. The adjustment, climb rate, and number of decimal places are all changed accordingly, after this function call.

     spin-button
          a <gtk-spin-button>.

     adjustment
          a <gtk-adjustment>.

     climb-rate
          the new climb rate.

     digits
          the number of decimal places to display in the spin button.

 -- Function: gtk-spin-button-new (adjustment <gtk-adjustment>) (climb_rate double) (digits unsigned-int) =>  (ret <gtk-widget>)
     Creates a new <gtk-spin-button>.

     adjustment
          the <gtk-adjustment> object that this spin button should use.

     climb-rate
          specifies how much the spin button changes when an arrow is clicked on.

     digits
          the number of decimal places to display.

     ret
          The new spin button as a <gtk-widget>.

 -- Function: gtk-spin-button-new-with-range (min double) (max double) (step double) =>  (ret <gtk-widget>)
     This is a convenience constructor that allows creation of a numeric <gtk-spin-button> without manually creating an adjustment. The value is initially set to the minimum value and a page increment of 10 * STEP is the default. The precision of the spin button is equivalent to the precision of STEP.

     Note that the way in which the precision is derived works best if STEP is a power of ten. If the resulting precision is not suitable for your needs, use gtk-spin-button-set-digits to correct it.

     min
          Minimum allowable value

     max
          Maximum allowable value

     step
          Increment added or subtracted by spinning the widget

     ret
          The new spin button as a <gtk-widget>.

 -- Function: gtk-spin-button-set-adjustment (self <gtk-spin-button>) (adjustment <gtk-adjustment>)
 -- Method: set-adjustment
     Replaces the <gtk-adjustment> associated with SPIN-BUTTON.

     spin-button
          a <gtk-spin-button>

     adjustment
          a <gtk-adjustment> to replace the existing adjustment

 -- Function: gtk-spin-button-get-adjustment (self <gtk-spin-button>) =>  (ret <gtk-adjustment>)
 -- Method: get-adjustment
     Get the adjustment associated with a <gtk-spin-button>

     spin-button
          a <gtk-spin-button>

     ret
          the <gtk-adjustment> of SPIN-BUTTON

 -- Function: gtk-spin-button-set-digits (self <gtk-spin-button>) (digits unsigned-int)
 -- Method: set-digits
     Set the precision to be displayed by SPIN-BUTTON. Up to 20 digit precision is allowed.

     spin-button
          a <gtk-spin-button>

     digits
          the number of digits after the decimal point to be displayed for the spin button's value

 -- Function: gtk-spin-button-set-increments (self <gtk-spin-button>) (step double) (page double)
 -- Method: set-increments
     Sets the step and page increments for spin_button. This affects how quickly the value changes when the spin button's arrows are activated.

     spin-button
          a <gtk-spin-button>

     step
          increment applied for a button 1 press.

     page
          increment applied for a button 2 press.

 -- Function: gtk-spin-button-set-range (self <gtk-spin-button>) (min double) (max double)
 -- Method: set-range
     Sets the minimum and maximum allowable values for SPIN-BUTTON

     spin-button
          a <gtk-spin-button>

     min
          minimum allowable value

     max
          maximum allowable value

 -- Function: gtk-spin-button-get-value-as-int (self <gtk-spin-button>) =>  (ret int)
 -- Method: get-value-as-int
     Get the value SPIN-BUTTON represented as an integer.

     spin-button
          a <gtk-spin-button>

     ret
          the value of SPIN-BUTTON

 -- Function: gtk-spin-button-set-value (self <gtk-spin-button>) (value double)
 -- Method: set-value
     Set the value of SPIN-BUTTON.

     spin-button
          a <gtk-spin-button>

     value
          the new value

 -- Function: gtk-spin-button-set-update-policy (self <gtk-spin-button>) (policy <gtk-spin-button-update-policy>)
 -- Method: set-update-policy
     Sets the update behavior of a spin button. This determines whether the spin button is always updated or only when a valid value is set.

     spin-button
          a <gtk-spin-button>

     policy
          a <gtk-spin-button-update-policy> value

 -- Function: gtk-spin-button-set-numeric (self <gtk-spin-button>) (numeric bool)
 -- Method: set-numeric
     Sets the flag that determines if non-numeric text can be typed into the spin button.

     spin-button
          a <gtk-spin-button>

     numeric
          flag indicating if only numeric entry is allowed.

 -- Function: gtk-spin-button-spin (self <gtk-spin-button>) (direction <gtk-spin-type>) (increment double)
 -- Method: spin
     Increment or decrement a spin button's value in a specified direction by a specified amount.

     spin-button
          a <gtk-spin-button>

     direction
          a <gtk-spin-type> indicating the direction to spin.

     increment
          step increment to apply in the specified direction.

 -- Function: gtk-spin-button-set-wrap (self <gtk-spin-button>) (wrap bool)
 -- Method: set-wrap
     Sets the flag that determines if a spin button value wraps around to the opposite limit when the upper or lower limit of the range is exceeded.

     spin-button
          a <gtk-spin-button>

     wrap
          a flag indicating if wrapping behavior is performed.

 -- Function: gtk-spin-button-set-snap-to-ticks (self <gtk-spin-button>) (snap_to_ticks bool)
 -- Method: set-snap-to-ticks
     Sets the policy as to whether values are corrected to the nearest step increment when a spin button is activated after providing an invalid value.

     spin-button
          a <gtk-spin-button>

     snap-to-ticks
          a flag indicating if invalid values should be corrected.

 -- Function: gtk-spin-button-update (self <gtk-spin-button>)
 -- Method: update
     Manually force an update of the spin button.

     spin-button
          a <gtk-spin-button>

 -- Function: gtk-spin-button-get-digits (self <gtk-spin-button>) =>  (ret unsigned-int)
 -- Method: get-digits
     Fetches the precision of SPIN-BUTTON. See gtk-spin-button-set-digits.

     spin-button
          a <gtk-spin-button>

     ret
          the current precision

 -- Function: gtk-spin-button-get-increments (self <gtk-spin-button>) =>  (step double) (page double)
 -- Method: get-increments
     Gets the current step and page the increments used by SPIN-BUTTON. See gtk-spin-button-set-increments.

     spin-button
          a <gtk-spin-button>

     step
          location to store step increment, or #f

     page
          location to store page increment, or #f

 -- Function: gtk-spin-button-get-numeric (self <gtk-spin-button>) =>  (ret bool)
 -- Method: get-numeric
     Returns whether non-numeric text can be typed into the spin button. See gtk-spin-button-set-numeric.

     spin-button
          a <gtk-spin-button>

     ret
          #t if only numeric text can be entered

 -- Function: gtk-spin-button-get-range (self <gtk-spin-button>) =>  (min double) (max double)
 -- Method: get-range
     Gets the range allowed for SPIN-BUTTON. See gtk-spin-button-set-range.

     spin-button
          a <gtk-spin-button>

     min
          location to store minimum allowed value, or #f

     max
          location to store maximum allowed value, or #f

 -- Function: gtk-spin-button-get-snap-to-ticks (self <gtk-spin-button>) =>  (ret bool)
 -- Method: get-snap-to-ticks
     Returns whether the values are corrected to the nearest step. See gtk-spin-button-set-snap-to-ticks.

     spin-button
          a <gtk-spin-button>

     ret
          #t if values are snapped to the nearest step.

 -- Function: gtk-spin-button-get-value (self <gtk-spin-button>) =>  (ret double)
 -- Method: get-value
     Get the value in the SPIN-BUTTON.

     spin-button
          a <gtk-spin-button>

     ret
          the value of SPIN-BUTTON

 -- Function: gtk-spin-button-get-wrap (self <gtk-spin-button>) =>  (ret bool)
 -- Method: get-wrap
     Returns whether the spin button's value wraps around to the opposite limit when the upper or lower limit of the range is exceeded. See gtk-spin-button-set-wrap.

     spin-button
          a <gtk-spin-button>

     ret
          #t if the spin button wraps around