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The condition `` expr1 = expr2'' tests whether the
expressions expr1 and expr2 are equal. There are several
possibilities:
- expr1 and expr2 are strings, symbols or numbers.
- In this
case expr1 and expr2 must be identical.
- expr1 and expr2 are lists.
- In this case expr1
and expr2 must match element by element.
- expr1 and expr2 are records.
- In this case expr1
and expr2 must contain the same attributes (though not necessarily in
the same order) as in expr2.
For nested structures, equality is tested recursively.
If expr1 and expr2 do not have the same type, the test
results in an error; only the symbol nil can be compared to any value.
The comparison `` expr1 /= expr2'' holds iff the
comparison `` expr1 = expr2'' does not hold.
Bjoern Beutel