Re: scope of function definition

Leon Bottou <[email protected]> Mon, 25 Apr 2005 14:58:01 -0400
Newsgroups	gmane.lisp.lush.devel
Message-ID	<[email protected]>
On Monday 25 April 2005 02:01 pm, Leon Bottou wrote:
> On Monday 25 April 2005 12:22 pm, Ralf Juengling wrote:
> > Clearly, lush is neither CL nor scheme. However, whenever you 
> > adopt a construct from either CL or scheme, it would be better to
> > keep with the established name for it. Currently, <defvar> in lush 
> > and <defvar> in CL have different semantics. In fact, lush's 
> > <defvar> mimics Cl's <defparameter>.
> 
> I could emulate the defvar/defparameter semantic.
Done


> > You might add a <defmacro> as a globally binding version of <dm> as well.
Done.



------------------------------------------------------------------------
(defvar <name> [<val>])                       [DM](sysenv.lsh)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Defines a new global variable name . Argument name must be an unquoted
symbol.
* If there was already an existing global variable name , function
  defvar does nothing. Argument val is not even evaluated.
* If there was no existing global variable name , function defvar
  defines such a global variable, and initializes it with the result of
  the evaluation of argument val .

Traditionally function setq was used for that purpose in SN/TLisp
because there was no notion of undefined global variables. All undefined
global variables were assumed to contain an empty list. This behavior
was the source of many bugs. The lush kernel now prints a warning when
using setq to define a new global variable.


------------------------------------------------------------------------
(defparameter <name> [<val>])                 [DM](sysenv.lsh)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

* See: (defvar name [ val ])


Defines a new global variable name initialized with value val . Argument
name must be an unquoted symbol. Unlike defvar , this function
unconditionally evaluates val and sets the variable value.


------------------------------------------------------------------------
(defun <name> <args> ...<body>...)            [DM](sysenv.lsh)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

* See: (de symb args . body )
* See: (defmacro name args ... body ...)
* See: (defvar name [ val ])


Function defun defines a global DE function named name . Whereas
function de defines symbol name in the current scope, function defun
defines symbol name in the global scope.


------------------------------------------------------------------------
(defmacro <name> <args> ...<body>...)         [DM](sysenv.lsh)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

* See: (de symb args . body )
* See: (defun name args ... body ...)
* See: (defvar name [ val ])


Function defun defines a global DM function named name . Whereas
function dm defines symbol name in the current scope, function defun
defines symbol name in the global scope. The argument list args only
matches the arguments of the macro. It should not contain a symbol for
matching the function name itself.



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