diff options
Diffstat (limited to 'prolog/problems/family_relations/sister_2/en.py')
| -rw-r--r-- | prolog/problems/family_relations/sister_2/en.py | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/prolog/problems/family_relations/sister_2/en.py b/prolog/problems/family_relations/sister_2/en.py index cbd975b..46babf0 100644 --- a/prolog/problems/family_relations/sister_2/en.py +++ b/prolog/problems/family_relations/sister_2/en.py @@ -45,8 +45,9 @@ For example: <code>X \== Y</code></p> ''', 'neq+_instead_of_neq': '''\ -<p>Use the operator \== instead of operators \= or =\=. It succeeds when the two operands are not the same, -while \= succeeds if the operands <em>cannot be made</em> the same (cannot be unified), and =\= checks for +<p>Use the operator <code>\==</code> instead of operators <code>\=</code> or <code>=\=</code>. +It succeeds when the two operands are not the same, +while <code>\=</code> succeeds if the operands <em>cannot be made</em> the same (cannot be unified), and <code>=\=</code> checks for arithmetic inequality and in this case both operands should be immediately arithmetically computable.</p> ''', @@ -75,7 +76,8 @@ something similarly impossible).</p> ''', 'final_hint': '''\ -<p>In this exercise you used the \== operator. It succeeds if its two operands are not the same +<p>In this exercise you used the <code>\==</code> (or <code>\=</code>) operator. +It succeeds if its two operands are not the same <em>at the moment</em> of comparison. If you put this goal at the start of your rule, it will not work as expected. (Go ahead, try and see what happens!)</p> ''', |