Info Catalog calc: Data Type Formats calc: Internals calc: Stack Lisp Functions

calc: Interactive Lisp Functions

 
 18.5.7.2 Interactive Functions
 ..............................
 
 The functions described here are used in implementing interactive Calc
 commands.  Note that this list is not exhaustive!  If there is an
 existing command that behaves similarly to the one you want to define,
 you may find helpful tricks by checking the source code for that
 command.
 
  -- Function: calc-set-command-flag flag
      Set the command flag FLAG.  This is generally a Lisp symbol, but
      may in fact be anything.  The effect is to add FLAG to the list
      stored in the variable ‘calc-command-flags’, unless it is already
      there.  Defining Simple Commands.
 
  -- Function: calc-clear-command-flag flag
      If FLAG appears among the list of currently-set command flags,
      remove it from that list.
 
  -- Function: calc-record-undo rec
      Add the “undo record” REC to the list of steps to take if the
      current operation should need to be undone.  Stack push and pop
      functions automatically call ‘calc-record-undo’, so the kinds of
      undo records you might need to create take the form ‘(set SYM
      VALUE)’, which says that the Lisp variable SYM was changed and had
      previously contained VALUE; ‘(store VAR VALUE)’ which says that the
      Calc variable VAR (a string which is the name of the symbol that
      contains the variable’s value) was stored and its previous value
      was VALUE (either a Calc data object, or ‘nil’ if the variable was
      previously void); or ‘(eval UNDO REDO ARGS ...)’, which means that
      to undo requires calling the function ‘(UNDO ARGS ...)’ and, if the
      undo is later redone, calling ‘(REDO ARGS ...)’.
 
  -- Function: calc-record-why msg args
      Record the error or warning message MSG, which is normally a
      string.  This message will be replayed if the user types ‘w’
      (‘calc-why’); if the message string begins with a ‘*’, it is
      considered important enough to display even if the user doesn’t
      type ‘w’.  If one or more ARGS are present, the displayed message
      will be of the form, ‘MSG: ARG1, ARG2, ...’, where the arguments
      are formatted on the assumption that they are either strings or
      Calc objects of some sort.  If MSG is a symbol, it is the name of a
      Calc predicate (such as ‘integerp’ or ‘numvecp’) which the
      arguments did not satisfy; it is expanded to a suitable string such
      as “Expected an integer.” The ‘reject-arg’ function calls
      ‘calc-record-why’ automatically; Predicates.
 
  -- Function: calc-is-inverse
      This predicate returns true if the current command is inverse,
      i.e., if the Inverse (‘I’ key) flag was set.
 
  -- Function: calc-is-hyperbolic
      This predicate is the analogous function for the ‘H’ key.
 

Info Catalog calc: Data Type Formats calc: Internals calc: Stack Lisp Functions