Binding Strength
For two entities X and Y that are adjacent in an expression (that is, X Y), the binding strength between them and
the result of the bind is shown in this table:
| Y | ||||||||
|---|---|---|---|---|---|---|---|---|
| A | F | H | MOP | DOP | DOT | IDX | ||
| X | A |
6
A
|
3
AF
|
3
AF
|
4
F
|
|
7
REF
|
4
A
|
| F |
2
A
|
1
F
|
4
F
|
4
F
|
4
F
|
|||
| H |
|
1
F
|
4
F
|
4
F
|
4
H
|
|||
| AF |
2
A
|
1
F
|
||||||
| MOP |
4
ERR
|
|||||||
| DOP |
5
MOP
|
5
MOP
|
5
MOP
|
|||||
| JOT |
5
MOP
|
5
MOP
|
5
MOP
|
4
F
|
||||
| DOT |
6
ERR
|
5
MOP
|
5
MOP
|
6
ERR
|
||||
| REF |
7
A
|
7
F
|
7
H
|
7
MOP
|
7
DOP
|
|||
| IDX |
3
ERR
|
3
ERR
|
3
ERR
|
|||||
where
- A: Array1, for example,
0 1 2 'hello' ⍺ ⍵ - F: Function1 {primitive | defined | derived | system}, for example,
+ - +.× myfn ⎕CR {⍺ ⍵} - H: Hybrid1 function/operator, that is,
/ ⌿ \ ⍀ - AF: Bound left argument, for example,
2+ - MOP: Monadic operator1, for example,
¨ ⍨ & - DOP: Dyadic operator, for example,
⍣ ⍠ ⍤ ⌸ - JOT: Jot, that is, compose/null operand
∘ - DOT: Dot, that is, reference/product
. - IDX: square-bracketed expression, for example,
[⍺+⍳⍵] - ERR: Error
In this table:
- the higher the number, the stronger the binding
- an empty field indicates no binding for this combination; an error.
For example, in the expression a b.c[d], where a, b, c and d are arrays, the binding proceeds:
a b . c [d]
6 7 6 4 ⍝ binding strengths between entities
→ a (b.) c [d]
0 7 4
→ a (b.c) [d]
6 4
→ (a(b.c))[d]