local (named (gasp / controversial)) parameters to a defined word

[nmorse]

(e.g.
[m:number x:number b:number]
[m x * b +] [my-linear-function]
define-with-named-args
)
or how to implement the quadratic formula.

[nmorse]

Even if named vars can be considered (a bite out of pure point-free).

# discriminant (with locally named args)
2 3 4 quo [c] def quo [b] def quo [a] def
b dup * 4 a * c * -
# >>> -23
## but the problem is that we really don't want args defined globally, so...
[a b c] [b dup * 4 a * c * -] [discriminant] define
2 3 4 discriminant
# >>> -23

The alternate pure point-free is a tangle of stack shufflers.

[nmorse]

[a b c op] [b -1 * b b * 4 a * c * squareroot  op 2 a * /] [quadratic-crossing]
[a b c] [a b c discriminant dup 0 < [[]] if dup 0 > [[ a b c [+] quadratic-crossing] ...] [] if-else] [quadratic]

manageable with the local-defined values (words) , but the stack swapping version is too complex to show here.

[nmorse]

since define has matured into a useful construct with local-words, adding named-args
(e.g. named-args:[x y]) to consume stack arguments into getters to be used in the definition and local-words seem like an interesting enough idea to pursue.

{named-args: [a b c]
 local-words: { discriminant: [ ... ] quadratic-crossing: [ ... ] ... }
 definition: [a b c discriminant dup 0 < [[]] if dup 0 > [[ a b c [+] quadratic-crossing] ...]
} [quad] define