features.md

Polarity search

A Hoogle-like type-based search for libraries that are in merlin's scope.

The commands :MerlinSearch (vim) / merlin-search (emacs) take a search query and return the list of identifiers that satisfy this query.

The query language is simply a list of path identifiers prefixed by + or -, e.g. -int, -int +string, -Hashtbl.t +int.

- is interpreted as "consuming" and + as "producing": -int +string looks for functions consuming an int and producing a string.

The search algorithm uses type variance to filter results. Thus, search will proceed inside abstract types, continuation-passing-style, ... as long as variance annotations are available.

Open refactoring

Merlin provides a pair of commands to help cleaning the code in the scope of an open statement.

Two new commands (:MerlinRefactorOpen, :MerlinRefactorOpenQualify in vim, and merlin-refactor-open, merlin-refactor-open-qualify in Emacs) help cleaning the code in the scope of an open statement.

When the cursor is on an open statement:

• :MerlinRefactorOpen (vim) / merlin-refactor-open (emacs) will remove references to the path of the open that are made useless
• :MerlinRefactorOpenQualify (vim) / merlin-refactor-open-qualify (emacs) will always add references to this path

Starting from:

open Unix

let times = Unix.times ()
let f x = x.Unix.tms_stime, x.Unix.tms_utime

Calling :MerlinRefactorOpen with the cursor on the open statement will produce:

open Unix

let times = times ()
let f x = x.tms_stime, x.tms_utime

Calling :MerlinRefactorOpenQualify will restore:

open Unix

let times = Unix.times ()
let f x = x.Unix.tms_stime, x.Unix.tms_utime