[erlang-questions] Illegal Guard?

Rad Gruchalski <>
Fri Feb 5 13:51:31 CET 2016


It’s explained here: http://erlang.org/doc/reference_manual/expressions.html#id83710  
The set of valid guard expressions (sometimes called guard tests) is a subset of the set of valid Erlang expressions. The reason for restricting the set of valid expressions is that evaluation of a guard expression must be guaranteed to be free of side effects.










Kind regards,

Radek Gruchalski

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de.linkedin.com/in/radgruchalski/ (http://de.linkedin.com/in/radgruchalski/)

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On Friday, 5 February 2016 at 13:40, Theepan wrote:

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> Team - Any idea?
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> 60> is_integer(A = 5).                        
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> true
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> 61>  
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> 61> fun () when is_integer(A = 5) -> ok end.   
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> * 2: illegal guard expression
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> 62> fun () when is_integer(5) -> ok end.      
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> #Fun<erl_eval.20.54118792>
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> 63> fun (A = 5) when is_integer(A) -> ok end.  
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> #Fun<erl_eval.6.54118792>
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> _______________________________________________
> erlang-questions mailing list
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