The keywords over and scan are covers for the accumulating iterators, Over and Scan. It is good style to use over and scan with unary and binary values.

Just as with Over and Scan, over and scan share the same syntax and perform the same computation; but while scan returns the result of each evaluation, over returns only the last.

See the Accumulators for a more detailed discussion.

Converge

 v1 over x    over[v1;x]        v1 scan x    scan[v1;x]
(vv)over x    over[vv;x]       (vv)scan x    scan[vv;x]

Where

• v1 is a unary applicable value
• vv is a variadic applicable value

applies the value progressively to x, then to v1[x] (or vv[x]), and so on, until the result matches (within comparison tolerance) either

• the previous result; or
• x.

q)n:("the ";("quick ";"brown ";("fox ";"jumps ";"over ");"the ");("lazy ";"dog."))
q)raze over n
"the quick brown fox jumps over the lazy dog."
q)(,/)over n
"the quick brown fox jumps over the lazy dog."
q){x*x} scan .01
0.01 0.0001 1e-08 1e-16 1e-32 1e-64 1e-128 1e-256 0

See the Accumulators for more detail, and for the related forms Do and While.