A bunch of utilities that you might find in interesting functional and/or function-level languages.
A bunch of utilities that you might find in interesting functional and/or function-level languages.
(!pred p f)(!pred p f ex-dispatch)A higher-order function that creates a validated wrapper around another function. Given a predicate p, a function f, and an optional exception handler ex-dispatch, a closure is returned that executes f with the provided arguments, the result is checked against p. If p returns true then the closure throws according to the exception dispatch. If ex-dispatch is a string or a map then that data is used to form the relevant contents of an ex-info packet. If ex-dispatch is a fn then the arguments given to the closure are passed to it and a Throwable is expected as its return.
If the predicate returns false, it returns the result unchanged.
A higher-order function that creates a validated wrapper around another function. Given a predicate p, a function f, and an optional exception handler ex-dispatch, a closure is returned that executes f with the provided arguments, the result is checked against p. If p returns true then the closure throws according to the exception dispatch. If ex-dispatch is a string or a map then that data is used to form the relevant contents of an ex-info packet. If ex-dispatch is a fn then the arguments given to the closure are passed to it and a Throwable is expected as its return. If the predicate returns false, it returns the result unchanged.
(downto end start)Generates an descending lazy sequence of numbers from start (inclusive) down to but not including end.
Generates an descending lazy sequence of numbers from start (inclusive) down to but not including end.
(foldr f acc [h & t :as coll])Right-associative fold over a collection. Unlike reduce (which is left-associative and processes elements left-to-right), foldr processes elements right-to-left by recursing to the end of the collection first, then applying the function f as the recursion unwinds.
reduce computes: f(f(f(acc, x1), x2), x3)foldr computes: f(x1, f(x2, f(x3, acc)))This difference matters when:
Right-associative fold over a collection. Unlike reduce (which is left-associative and processes elements left-to-right), foldr processes elements right-to-left by recursing to the end of the collection first, then applying the function f as the recursion unwinds. - `reduce` computes: f(f(f(acc, x1), x2), x3) - `foldr` computes: f(x1, f(x2, f(x3, acc))) This difference matters when: 1. The operation is non-associative (e.g., division, subtraction, list cons) 2. You need to build right-associative data structures (e.g., linked lists) 3. You want lazy evaluation (foldr can short-circuit on lazy sequences) 4. The combining function needs to see the 'rest result' before processing current
(iota t nxt stop y)Generates a lazy sequence by repeatedly applying a transformation function t to the result of a next-step function nxt, starting from initial value y, and continuing while the stop predicate is truthy. This is a generalized iteration function for creating sequences with custom stepping and transformation logic.
Generates a lazy sequence by repeatedly applying a transformation function t to the result of a next-step function nxt, starting from initial value y, and continuing while the stop predicate is truthy. This is a generalized iteration function for creating sequences with custom stepping and transformation logic.
(to start end)Generates a lazy sequence from start to end (exclusive), automatically choosing ascending or descending direction based on the relationship between start and end values.
Generates a lazy sequence from start to end (exclusive), automatically choosing ascending or descending direction based on the relationship between start and end values.
(upto end start)Generates an ascending lazy sequence of numbers from start (inclusive) up to but not including end.
Generates an ascending lazy sequence of numbers from start (inclusive) up to but not including end.
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