Unfold may refer to:
In category theory, the concept of anamorphism ("ana" from the Greek ἀνά = upwards; "morphism" from the Greek μορφή = form, shape) denotes a morphism from a coalgebra to the final coalgebra for that endofunctor. These objects have been applied to functional programming as unfolds. The categorical dual of the anamorphism is the catamorphism.
In functional programming, an anamorphism is a generalization of the concept of unfolds on lists. Formally, anamorphisms are generic functions that can corecursively construct a result of a certain type and which is parameterized by functions that determine the next single step of the construction.
An unfold on lists would build a (potentially infinite) list from a seed value. Typically, the unfold takes a seed value x
, a one-place operation unspool
that yields a pairs of such items, and a predicate finished
which determines when to finish the list (if ever). In the action of unfold, the first application of unspool
, to the seed x
, would yield unspool x => (y,z)
. The list defined by the unfold would then begin with y
and be followed with the (potentially infinite) list that unfolds from the second term, z
, with the same operations. So if unspool z => (u,v)
, then the list will begin y:u:...
, where ...
is the result of unfolding v with r, and so on.
Almah is a Brazilian metal band. It was initially established in 2006 as a side project of former Angra’s singer Edu Falaschi. Since 2006 Almah has released three albums and has turned from a solo-project into a band with regular activities. The band released its third album entitled "Motion" in October 2011. "Motion" was recorded at Norcal Studios in São Paulo, Brasil between May and June 2011. The album was mixed and mastered by Jochem Jacobs at Split Second Sound Studios in Amsterdam in July 2011. They released theirfourth album "Unfold" in 2013, and a compilation titled "Within The Last Eleven Lines" in 2015.
The first self-titled Almah was released in the second half of 2006 (Japan/Victor-JVC and Brazil/Laser Company) / in March 2007 (Europe/AFM Records). Besides singing, Edu Falaschi also produced the record, composed all the songs and wrote all the lyrics. He recorded acoustic guitars and keyboards and created all the arrangements for every instrument, including orchestrations. The album was recorded in Finland and Brazil with the following musicians: Emppu Vuorinen (guitars – Nightwish), Lauri Porra (bass – Stratovarius) and Casey Grillo (drums – Kamelot) and special guest appearances: Mike Stone (guitars – Queensrÿche), Edu Ardanuy (guitars – Dr. Sin) and Sizão Machado (bass – Tom Jobim, Chico Buarque and others) among others.