@replace(t:tab, find:value, rep:value)
returns a new tab in which a number of elements have been replaced by another.

The argument find represents a sub-sequence to be replaced: if it is not a tab, then all the occurrences of this value at the top-level of t are replaced by rep: 

       $t := [1, 2, 3, [2]]
       @replace($t, 2, 0) -> [1, 0, 3, [2]]
If find is a tab, then the replacement is done on sub-sequence of t: 
       @replace([1, 2, 3, 1, 2], [1, 2], 0) -> [0, 3, 0]
Note that the replacement is done eagerly: the first occurrence found is replaced and the replacement continue on the rest of the tab. Thus, there is no ambiguity in case of overlapping sub-sequences, only the first is replaced: 
       @replace([1, 1, 1, 2], [1, 1], 0) -> [0, 1, 2]
If the argument `rep is a tab, then it represents at sub-sequence to be inserted in place of the occurrences of find. So, if the replacement is a tab, it must be wrapped into a tab: 
       @replace([1, 2, 3], 2, [4, 5]) -> [1, 4, 5, 3]
       @replace([1, 2, 3], 2, [[4, 5]]) -> [1, [4, 5], 3]

See also Tab Manipulations @car,    @cdr,    @clear,    @concat,    @cons,    @copy,    @count,    @dim,    @domain,    @drop,    @empty,    @find,    @flatten,    @gnuplot,    @insert,    @iota,    @is_list,    @is_prefix,    @is_subsequence,    @is_suffix,    @lace,    @last,    @listify,    @map,    @max_val,    @median,    @member,    @normalize,    @occurs,    @parse,    @permute,    @push_back,    @push_front,    @range,    @reduce,    @remove,    @remove_duplicate,    @replace,    @reshape,    @resize,    @reverse,    @rotate,    @scan,    @scramble,    @size,    @slice,    @sort,    @sputter,    @stutter,    @succession,    @tab_history,    @tab_history_date,    @tab_history_rdate,    @take    @to_num