preposition — Newfoundland, Prince Edward Island and Cape Breton, elsewhere dated or historical
in the construction be + after + present participle, after specifies perfective aspect.
Type: 2. Preservation — There is good evidence that the construction is a Canadian preservation of a transplanted and adapted Irish English construction. DARE, s.v. "after (B.1)" lists a 1792 quotation in an Irish-American context, with the most recent quotation dating from 1926, while it is in contemporary use in some Atlantic Canadian dialects.
After, preceded by be and followed by a present participle, is one of the most discussed grammatical constructions of Newfoundland and Labrador English. Clarke (2010b: 79) notes that the "after-perfect" is a preservation from Irish and Scottish English, and was thus originally most prominent in the Irish- (and Scottish-) settled parts of Newfoundland. The construction is also reported in the English dialects of PEI and the Ottawa Valley, which are also Irish-settled areas. The construction is originally based on substrate influence from an Old Irish syntactic feature and was used, from about 1600 onwards (Hickey 2007: 199), to refer to both future (see the 1889 quotation - "I will/would be reminding ye") and immediate past in Irish English, with future meaning declining drastically after 1850 (McCafferty 2004: 139, Table 3). Present-Day Irish English allows only the meaning of 'immediate, recent past' (Hickey 2007: 204) and since the mid-19th century in Irish English it can generally be seen as equivalent to "have just done", with the emphasis on the recency of the action (OED-3, "after" (P5.b).
Another use of the construction is for the general or distant, rather than the immediate past. Bismark (2008: 100) argues that the use of the after construction in Newfoundland differs in this respect from Irish English, though the construction is also reported there for much of the 20th century (McCafferty 2014: 212-13). The construction "be after doing" in Newfoundland can suggest a whole range of meanings similar to some "have" resultative perfect constructions, but the predominant meaning was found to refer to actions done at any time in the past (Bismark 2008: 103-105). Though the construction is clearly Irish in origin, the after perfect frequently appears in the parts of Newfoundland that contain a dialect derived from West Country English. In Ireland, the general perfect is used in the South (McCafferty personal communication). It therefore stands to reason that the construction was reallocated to a new meaning as a result of dialect mixing processes (Trudgill 2004: 84-89). This offers a possible explanation for the semantic generalization from immediate past to general past, as the West Country and Irish English speakers would have generalized its meaning, possibly in analogy to the "have" perfect (Trudgill 1986: 152).
See also DNE, s.v. "after", DPEIE, s.v. "after" and DCBE, s.v. "after", the latter of which attesting the form in present-day English (the 2000s) in both the recent and general past.