Return a Boolean value indicating if a number is greater than or equal to -zero.
... b a <{}
+zero. ... b a <{}
-----------------
... [] b a
Tuck an empty list just under the first two items on the stack.
... a <{}
----------------
... [] a
-Tuck an empty list just under the first item on the stack.
Is the item on the top of the stack "truthy"?
You often want to test the truth value of an item on the stack without +
Tuck an empty list just under the first item on the stack.
Is the item on the top of the stack "truthy"?
You often want to test the truth value of an item on the stack without consuming the item.
combinator
Build a list of values from a generator program G and a stopping
predicate P.
[P] [G] anamorphism
@@ -113,7 +113,7 @@ empty list is false and all other lists are true.<
T
This is one of the fundamental operations (although it can be defined in terms of [choice] as above). The more common "if..then..else" construct -[ifte] adds a predicate function that is evaluated [nullary].
a b c d [...] ccccons
+[ifte] adds a predicate function that is evaluated [nullary]. a b c d [...] ccccons
---------------------------
[a b c d ...]
dip combinator could "set aside" t
item and replace it after running Q but that means that there is an
"extra space" where the item resides while Q runs. One of the nice
things about CPS is that the whole state is recorded in the stack and
-pending expression (not counting modifications to the dictionary.)combinator
Like [dip] but expects two items.
+pending expression (not counting modifications to the dictionary.)combinator
Like [dip] but expects two items.
... y x [Q] . dipd
-------------------------
... . Q y x
@@ -264,7 +264,7 @@ items removed off the top.
a dup
-----------
a a
-
[dup] the second item down on the stack.
+[dup] the second item down on the stack.
a b dupd
--------------
a a b
@@ -303,7 +303,7 @@ them with a Boolean value.
[a ...]
--------------
a
-
Replace a list with its first two items.
+Replace a list with its first two items.
[a b ...] first_two
-------------------------
a b
@@ -404,7 +404,7 @@ example, the [x] combinator can be defined as dup i. [if] [then] [else] ifte
---------------------------------------
[if] nullary [else] [then] branch
-combinator
Take a quoted program from the stack and run it twice, first under the top item, then again with the top item.
... a [Q] ii
------------------
@@ -515,12 +515,12 @@ parallelism combinator due to the "pure" nature of the language. [1 2 3 4] max
-------------------
4
-Given a list find the minimum.
[1 2 3 4] min
-------------------
1
-Return the remainder of a divided by b.
a b mod
-------------
(a%b)
@@ -552,7 +552,7 @@ stack, replacing them with a Boolean value.
[[F] nullary]
Helper function for [or] and [and].
True if the item on the top of the stack is an empty list, false if it's a list but not empty, -and an error if it's not a list.
combinator
Run a quoted program without using any stack values and leave the first +and an error if it's not a list.
combinator
Run a quoted program without using any stack values and leave the first item of the result on the stack.
... [P] nullary
---------------------
@@ -614,11 +614,11 @@ the underlying [map] function is so implemented, of course.)[pop] the second item down on the stack.
+[pop] the second item down on the stack.
a b popd
--------------
b
-[pop] the third item on the stack.
+[pop] the third item on the stack.
a b c popdd
-----------------
b c
@@ -815,7 +815,7 @@ complement to the "destructive" pair [enstacken] and [disenstacken].See the Recursion Combinators notebook.
combinator
Like [step] but with 0 as the initial value.
+See the Recursion Combinators notebook.
combinator
Like [step] but with 0 as the initial value.
[...] [F] step_zero
-------------------------
0 [...] [F] step
@@ -920,7 +920,7 @@ the list. You cannot uncons an item from an empty list.
[a ...] uncons
--------------------
a [...]
-
This is the inverse of [cons].
Given a list remove duplicate items.
Given a list remove duplicate items.