lcons: Creates a pair, the right value is promised (by making...
In TobCap/lazystreamr: Provides basic functions that handle lazy stream objects

Description Usage Arguments Value References Examples

The idea and funcition names mainly comes from Scheme (Gauche) and Haskell. see References

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lhs %:% rhs

lcons(lhs, rhs)

`lhs`	car part
`rhs`	cdr part

lazy cons of lhs and rhs.

# R's infix operator has left-associativity
# run
1 %:% (2 %:% (3 %:% lempty))

# can be parsed but not llist
1 %:% 2 %:% 3 %:% lempty

# repeat 1L as an infinit sequence
ones <- 1L %:% ones

# this was privous version of lcons that evaluate a cdr part as eager-eval.
`%:%` <- lcons <- function(x, y) {
  `class<-`(pairlist(head = x, tail = function() y), "lcons")
}