single_var_warnings

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Article #660

#660

From: Dr D Stott Parker
Date: Wed, 19 Aug 1992 18:15

38 lines
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Regarding singleton variable warnings in SICStus Prolog,
there is actually a flag that can be used to suppress them:

	 (44) > sicstus0.7
	SICStus 0.7 #1: Fri Oct 25 09:12:35 PDT 1991
	| ?- prolog_flag(single_var_warnings,X,X).

	X = on ? 

	yes
	| ?- [user].      
	| test(X).   
	{Warning: [X] - singleton variables in test/1 in lines 10-11}
	| {user consulted, 0 msec 340 bytes}

	yes
	| ?- prolog_flag(single_var_warnings,_,off).

	yes
	| ?- [user].
	| test(X).
	| {user consulted, 0 msec 48 bytes}

	yes
	| ?- 

However, I think most Prolog programmers would strongly recommend leaving
it on.   A very large percentage of typing and simple logic errors in
Prolog programs are detected with these warnings; one will usually
save time by following the single-variable style discipline.

D. Stott Parker  (stott@cs.ucla.edu)  UCLA Computer Science Dept.
+1 (213) 825-6871, 825-1322 secy.     3532 Boelter Hall
+1 (213) 825-2273 FAX                 Los Angeles, CA 90024-1596  USA
-- 
D. Stott Parker  (stott@cs.ucla.edu)  UCLA Computer Science Dept.
+1 (213) 825-6871, 825-1322 secy.     3532 Boelter Hall
+1 (213) 825-2273 FAX                 Los Angeles, CA 90024-1596  USA

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From: stott@bop.cs.ucla.edu (Dr D Stott Parker)
Newsgroups: comp.lang.prolog
Subject: single_var_warnings
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Date: 19 Aug 92 18:15:51 GMT
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