What is Expressiveness in a Computer Language
jo at durchholz.org
Thu Jun 22 21:51:37 CEST 2006
> immutable = can't change
> vary-able = can change
> Clearly a contradiction in terms.
Not in mathematics.
The understanding there is that a "variable" varies - not over time, but
according to the whim of the usage. (E.g. if a function is displayed in
a graph, the parameter varies along the X axis. If it's used within a
term, the parameter varies depending on how it's used. Etc.)
Similarly for computer programs.
Of course, if values are immutable, the value associated with a
parameter name cannot vary within the same invocation - but it can still
vary from one invocation to the next.
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