Two beginner questions

[Urban Hafner]

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Hej everybody,
I'm currently learning Oz while reading Concepts, Techniques, and Models
of Computer Programming. While making the exercises of chapter 1 I
managed to write two bits of code that don't work like I want them to. I
hope someone can tell me what I'm doing wrong.

When I try to compile this bit of code:

declare Accum in
local C in
~   C={NewCell 0}
~   fun {Accum N}
~      D=@C
~   in
~      if N<=D
	 C:=D+N
~      else
	 C:=D-N
~      end
~      @C
~   end
end

I get this error message:

%*************************** parse error ************************
%**
%** expecting `then'
%**
%** in file "/Users/urban/blog/book/CTMCP/parse-error.oz", line 7, column 10
%** ------------------ rejected (1 error)

Seems like it doesn't like the 'if' after the 'in'. What's wrong here?

The second one one compiles just fine but I hangs in the 'A={NewStore}'
line. What's wrong here?

declare
fun {NewStore}
~   Cell Put Get Size SizeI in
~   Cell:={NewCell nil}
~   SizeI:={NewCell 0}

~   proc {Put N I}
~      fun {PutHelper S N I}
	 case S of Num|Val|T then
	    if Num==N then
	       N|I|T
	    else
	       Num|Val|{PutHelper T N I}
	    end
	 else
	    SizeI:=@SizeI+1
	    N|I|S
	 end
~      end
~   in
~      Cell:={PutHelper @Cell N I}
~   end

~   fun {Get N}
~      fun {GetHelper S N}
	 case S of Num|Val|T then
	    if Num==N then
	       Val
	    else
	       {GetHelper T N}
	    end
	 else
	    nil
	 end
~      end
~   in
~      {GetHelper @Cell N}
~   end

~   fun {Size}
~      @SizeI
~   end

~   store(put:Put get:Get size:Size)

end

declare A in
{Browse 0}
A={NewStore}
{Browse 1}
{Browse {A.size}}
{Browse 2}
{A.put 2 [22 23]}
{Browse 3}
{A.put 1 [21 243]}
{Browse 4}
{Browse {A.get 1}}
{Browse 5}

Thanks for your help,

	Urban
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