[erlang-bugs] Trivial typos in HTML doc/programming_examples/funs.html

G Bulmer <>
Mon Sep 24 21:43:16 CEST 2007


In the documentation file file:///usr/local/lib/erlang/doc/ 
programming_examples/funs.html#2.4,
the text "within within" should be "within"

Further down the same 2.4 section, the text refers to 'the first  
clause of F':

"The rules for importing variables into a fun has the consequence  
that certain pattern matching operations have to be moved into guard  
expressions and cannot be written in the head of the fun. For  
example, we might write the following code if we intend the first  
clause of F to be evaluated when the value of its argument is Y:"

Is followed by two examples:
"
f(...) ->
     Y = ...
     map(fun(X) when X == Y ->
              ;
            (_) ->
              ...
         end, ...)
     ...


instead of

f(...) ->
     Y = ...
     map(fun(Y) ->
              ;
            (_) ->
              ...
         end, ...)
     ...
"

This is unclear to me. Either the text could read 'the first clause  
of f' as there is no 'F', but I believe this is incorrect. IMHO the  
intent is to say 'the first clause of the fun' - it may be improved  
if that is qualified with 'the first clause of the fun in in "map 
(fun ...end, ...)"'.

Finally, it isn't immediately clear which of the two examples is  
correct (until you understand what is being explained :-)
So, extend 'instead of' say something more definitive like: 'instead  
of this incorrect form, where the parameter Y in fun(Y) hides the  
variable bound in Y=.., and hence that clause of the fun is called  
irresepctive of whether the parameter is the variable Y or not.'

These Erlang manuals and papers are very useful documentation. Well  
done, and thank you.
GB




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