Form field base class. See +CheckBox, +Radio, +TextField, +RgbPicker.
(field X . @)
Function to access another field from the current field. The first argument can be either a symbol (to access a named 'gui' component) or a positive or negative number (to access a field relative to the current one). In both cases the 'get' algorithm is applied to all following arguments.

    (gui '(+View +TextField) '(field -1 'obj 'ort) 30)
+FixField accepts and returns scaled fixpoint numbers. This field needs an argument that determines the scale factor.

    (gui '(+FixField) 3 10)
See also +NumField, +TextField and Input fields.
This field evaluates an 'exe' to find and open/create a file, then loads/modifies/stores the text in that file. See also +TextField.
+Focus is a prefix class used to set the keyboard focus on a specific GUI element. For example, it can be used to put the initial focus on a specific input field in a search dialog. Examples of this usage can be found in the demo app supplied with the PicoLisp distribution, in gui.l:

    (de choCuSu (Dst)
       (diaform '(Dst)
          (<grid> "--.-.-."
             ,"Number" (gui 'nr '(+Var +NumField) '*CuSuNr 10)
             ,"Name" (gui 'nm '(+Focus +Var +TextField) '*CuSuNm 30)
             ,"Phone" (gui 'tel '(+Var +TelField) '*CuSuTel 20)
             (searchButton '(init> (: home query)))
             ,"Zip" (gui 'plz '(+Var +TextField) '*CuSuPlz 10)
             ,"City" (gui 'ort '(+Var +TextField) '*CuSuOrt 30)
             ,"Mobile" (gui 'mob '(+Var +TelField) '*CuSuMob 20)
             (resetButton '(nr nm tel plz ort mob query)) )
In the code above, +Focus is used to give initial focus to the "Name" input field.
Button prefix class which may force the action even if an error occurred. Without it, an 'error' will always inhibit further button handling. See also +Button.
+Fmt is a prefix class that combines +Set and +Val, taking two functions as arguments. This example will display upper case characters, while returning lower case characters internally:

    (gui '(+Fmt +TextField) uppc lowc 30)
See also +Set, +Val and formatting.
The basic form function. Handles operations common to the concrete form types in the library. See idForm, diaform.