drscheme:modes:add-mode in DrScheme Tools Functions

• (drscheme:modes:add-mode name surrogate repl-submit matches-language) -> drscheme:modes:mode?
     name : string?
     surrogate : (union false? (is-a?/c mode:surrogate-text<%>))
     repl-submit : ((is-a?/c drscheme:rep:text%) number? . -> . boolean?)
     matches-language : ((union false? (listof string?)) . -> . boolean?)

  Adds a mode to DrScheme. Returns a mode value that identifies the mode.

  The first argument, name, is the name of the mode, used in DrScheme's GUI to allow the user to select this mode.

  The surrogate argument is set to the definitions text and the interactions text (via the set-surrogate method) whenever this mode is enabled.

  The repl-submit procedure is called whenever the user types a return in the interactions window. It is passed the interactions editor and the position where the last prompt occurs. If it returns #t, the text after the last prompt is treated as a program fragment and evaluated, according to the language settings. If it returns #f, the text is assumed to be an incomplete program fragment, and the keystroke is not treated specially.

  The matches-language predicate is called whenever the language changes. If it returns #t this mode is installed. It is passed the list of strings that correspond to the names of the language in the language dialog.

  Modes are tested in the opposite order that they are added. That is, the last mode to be added gets tested first when the filename changes or when the language changes.

  See also drscheme:modes:get-modes.