Re: Checking function syntax
- To: mathgroup at smc.vnet.net
- Subject: [mg64582] Re: [mg64555] Checking function syntax
- From: jmt <jmt at dxdydz.net>
- Date: Thu, 23 Feb 2006 00:34:19 -0500 (EST)
- References: <200602221058.FAA23476@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On Wednesday 22 February 2006 11:58, Chris Rodgers wrote:
> Hi,
>
> How can I make my own functions give an error if they are called with
> the wrong syntax?
Try this :
Here is your standard definition :
MyFunc1[x_, y_] := Tuples[{x, y}, 2]
Define your error message :
MyFunc1::"WrongInput" = "A sensible error message for incorrect input `1`"
Create the rule that match wrong input :
MyFunc1[u___] := Message[MyFunc1::"WrongInput", u]
Check normal function call :
Map[MyFunc2, MyFunc1[a, b]]
And incorrect one :
Map[MyFunc2, MyFunc1[a, b, c]]
Mind the fact that in some situations some rules might have equal priorities,
in which case rule definition ordering defines which rule will be called.
- References:
- Checking function syntax
- From: Chris Rodgers <rodgers@physchem.NOSPAMox.aREMOVEc.uk>
- Checking function syntax