[m-dev.] A chemical equation balancer

[Ralph Becket]

A buglet:

$ ./chem.
h2 -> h3
The number of Hs don't match (2 vs 3)
h2 -> o2   <--- oh dear
h3 -> h3

In the deobfuscated version you need to apply

--- chem.m      Wed May 16 11:51:06 2001
+++ chem.old    Wed May 16 11:54:51 2001
@@ -25,7 +25,7 @@
        ( { parse(LHS, RHS, Chars, []) } ->
            { solutions((pred({L, M, N}::out) is nondet :-
                member(LHS, L, N),
-               M = ( if search(RHS, L, M0) then M0 else 0 ),
+               member(RHS, L, M),
                N \= M
            ), Xs) },
            foldl((pred({I, J, K}::in, di, uo) is det -->

- Ralph

> -----Original Message-----
> From: Thomas Conway [mailto:conway at cs.mu.OZ.AU]
> Sent: 16 May 2001 02:49
> To: mercury-developers at cs.mu.OZ.AU
> Subject: [m-dev.] A chemical equation balancer
> 
> Hi
> 
> Here is a slightly obfuscated chemical equation balancer that we
> might like to deobfuscate (in a little while)[1] and add to the
> samples.
> 
> sample correct input:
>     CO2 + 2H2O -> O2 + CH4
> --
>   Thomas Conway )O+
>  <conway at cs.mu.oz.au>       499 User error! Replace user, and press
any key.
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