DyalogMigrationLevels

The system variable ⎕ML determines the degree of compatability of Dyalog APL towards IBM's APL2. In general, the value 0 represents "native Dyalog". The higher the value, the closer to APL2/

For the time being (2009), 3 is the highest level of compatability one can achieve.

Note that with a default installation ⎕ML is set to 1.

ML setting	APL	Remarks
`⎕ML←0`		Native Dyalog (Default)
`⎕ML←1`	`∊R`	Monadic `∊` is interpreted as 'enlist' rather than 'type'
`⎕ML←2`	`↑R`	Monadic `↑` is interpreted as 'first' rather than 'mix'
	`⊃R`	Monadic `⊃` is interpreted as 'mix' rather than 'first'
	`≡R`	For an array with unequal levels of nesting in its subarrays, depth returns the maximum level of nesting. With `⎕ml≤2` depth returns a negative value if the subarrays have unequal depth
`⎕ML←3`	`X⊂[K]Y`	Dyadic `⊂` follows the APL2 rather than the original Dyalog convention
	`⎕TC`	The order of the elements of `⎕TC` is the same as in APL2

CategoryDyalog