Mutation is seen as a necessary evil and is supported but segregated
in hopes of trying to isolate and optimize the nondestructive cases.
Mutation includes the notion of modifying values and adding/removing
keys. The hope is that functional (nondestructive) programs will be
both more succinct, understandable, and efficient than equivalent
destructive programs. Only core collection operators are given
destructive versions. All others can be built out of nondestructive
operators followed by into 1.
|
<col!> | (<any>) | C |
|
elt-setter | (v|<any> x|<col!> k|<any>) | G |
|
| sets collection x's element associated with key
k to v. | |
|
into | (x|<col!> y|<col> => <col!>) | G |
|
| replaces elements of x with elements of y. | |
|
elt! | (x|<col!> y|<any default|<fun> => <any>) | G |
|
| == (or (elt-or c k #f) (set (elt c k) (default))) but
uses unique default key for elt-or instead of false. | |
|
fill! | (x|<col!> y|<any> => <col!>) | G |
|
| fills x with y's. | |
|
add! | (x|<seq!> y|<any => <seq!>) | G |
|
| adds y to x. | |
|
del! | (x|<col!> key|<any> => <col!>) | G |
|
| removes key from x. | |
|
zap! | (x|<col!> => <col!>) | G |
|
| removes all of x's elements. | |
|
|
