[erlang-questions] style question - best way to test multiple non-guard conditions sequentially
Richard A. O'Keefe
Fri Jun 21 01:45:15 CEST 2013
On 21/06/2013, at 4:27 AM, Jonathan Leivent wrote:
> OK - that is surprising. That certainly changes my thinking about if statements. Is this particular semantic difference between guards and general conditions ever expressed in the reference manual? If so, I certainly missed it.
Yes it is.
Section 7.24 "Guard Sequences", where guards are described.
At the end, there is this sentence:
If an arithmetic expression, a boolean expression, a short-circuit
expression, or a call to a guard BIF fails (because of invalid
arguments), the entire guard fails . If the guard was part of
a guard sequence, the next guard in the sequence (that is, the
guard following the next semicolon) will be evaluated.
It's also explained clearly in the Erlang books I've read.
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