c67b8bccb9
- Expose `read`, `read_str`, and `eval` in Python - Add string evaluation example to interop section of docs - Add test for `eval` - Explain `eof` keyword argument in `read` docstring
490 lines
13 KiB
Hy
490 lines
13 KiB
Hy
;; Copyright 2017 the authors.
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;; This file is part of Hy, which is free software licensed under the Expat
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;; license. See the LICENSE.
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;;;; This contains some of the core Hy functions used
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;;;; to make functional programming slightly easier.
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;;;;
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(import itertools)
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(import functools)
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(import collections)
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(import [fractions [Fraction :as fraction]])
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(import operator) ; shadow not available yet
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(import sys)
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(if-python2
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(import [StringIO [StringIO]])
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(import [io [StringIO]]))
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(import [hy._compat [long-type]]) ; long for python2, int for python3
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(import [hy.models [HyCons HySymbol HyKeyword]])
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(import [hy.lex [LexException PrematureEndOfInput tokenize]])
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(import [hy.compiler [HyASTCompiler spoof-positions]])
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(import [hy.importer [hy-eval :as eval]])
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(defn butlast [coll]
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"Returns coll except of last element."
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(drop-last 1 coll))
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(defn coll? [coll]
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"Checks whether item is a collection"
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(and (iterable? coll) (not (string? coll))))
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(defn comp [&rest fs]
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"Function composition"
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(if (not fs) identity
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(= 1 (len fs)) (first fs)
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(do (setv rfs (reversed fs)
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first-f (next rfs)
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fs (tuple rfs))
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(fn [&rest args &kwargs kwargs]
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(setv res (first-f #* args #** kwargs))
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(for* [f fs]
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(setv res (f res)))
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res))))
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(defn complement [f]
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"Create a function that reverses truth value of another function"
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(fn [&rest args &kwargs kwargs]
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(not (f #* args #** kwargs))))
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(defn cons [a b]
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"Return a fresh cons cell with car = a and cdr = b"
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(HyCons a b))
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(defn cons? [c]
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"Check whether c can be used as a cons object"
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(instance? HyCons c))
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(defn constantly [value]
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"Create a function that always returns the same value"
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(fn [&rest args &kwargs kwargs]
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value))
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(defn keyword? [k]
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"Check whether k is a keyword"
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(and (instance? (type :foo) k)
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(.startswith k (get :foo 0))))
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(defn dec [n]
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"Decrement n by 1"
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(- n 1))
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(defn disassemble [tree &optional [codegen False]]
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"Return the python AST for a quoted Hy tree as a string.
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If the second argument is true, generate python code instead."
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(import astor)
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(import hy.compiler)
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(spoof-positions tree)
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(setv compiled (hy.compiler.hy-compile tree (calling-module-name)))
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((if codegen
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astor.codegen.to_source
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astor.dump)
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compiled))
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(defn distinct [coll]
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"Return a generator from the original collection with duplicates
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removed"
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(setv seen (set) citer (iter coll))
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(for* [val citer]
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(if (not_in val seen)
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(do
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(yield val)
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(.add seen val)))))
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(if-python2
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(def
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remove itertools.ifilterfalse
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zip-longest itertools.izip_longest
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;; not builtin in Python3
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reduce reduce
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;; hy is more like Python3
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filter itertools.ifilter
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input raw_input
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map itertools.imap
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range xrange
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zip itertools.izip)
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(def
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remove itertools.filterfalse
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zip-longest itertools.zip_longest
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;; was builtin in Python2
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reduce functools.reduce
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;; Someone can import these directly from `hy.core.language`;
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;; we'll make some duplicates.
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filter filter
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input input
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map map
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range range
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zip zip))
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(if-python2
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(defn exec [$code &optional $globals $locals]
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"Execute Python code.
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The parameter names contain weird characters to discourage calling this
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function with keyword arguments, which isn't supported by Python 3's
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`exec`."
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(if
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(none? $globals) (do
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(setv frame (._getframe sys (int 1)))
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(try
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(setv $globals frame.f_globals $locals frame.f_locals)
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(finally (del frame))))
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(none? $locals)
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(setv $locals $globals))
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(exec* $code $globals $locals))
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(def exec exec))
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;; infinite iterators
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(def
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count itertools.count
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cycle itertools.cycle
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repeat itertools.repeat)
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;; shortest-terminating iterators
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(def
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*map itertools.starmap
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chain itertools.chain
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compress itertools.compress
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drop-while itertools.dropwhile
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group-by itertools.groupby
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islice itertools.islice
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take-while itertools.takewhile
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tee itertools.tee)
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;; combinatoric iterators
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(def
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combinations itertools.combinations
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multicombinations itertools.combinations_with_replacement
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permutations itertools.permutations
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product itertools.product)
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;; also from itertools, but not in Python2, and without func option until 3.3
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(defn accumulate [iterable &optional [func operator.add]]
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"accumulate(iterable[, func]) --> accumulate object
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Return series of accumulated sums (or other binary function results)."
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(setv it (iter iterable)
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total (next it))
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(yield total)
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(for* [element it]
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(setv total (func total element))
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(yield total)))
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(defn drop [count coll]
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"Drop `count` elements from `coll` and yield back the rest"
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(islice coll count None))
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(defn drop-last [n coll]
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"Return a sequence of all but the last n elements in coll."
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(setv iters (tee coll))
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(map first (zip #* [(get iters 0)
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(drop n (get iters 1))])))
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(defn empty? [coll]
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"Return True if `coll` is empty"
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(= 0 (len coll)))
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(defn even? [n]
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"Return true if n is an even number"
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(= (% n 2) 0))
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(defn every? [pred coll]
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"Return true if (pred x) is logical true for every x in coll, else false"
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(all (map pred coll)))
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(defn flatten [coll]
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"Return a single flat list expanding all members of coll"
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(if (coll? coll)
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(_flatten coll [])
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(raise (TypeError (.format "{0!r} is not a collection" coll)))))
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(defn _flatten [coll result]
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(if (coll? coll)
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(do (for* [b coll]
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(_flatten b result)))
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(.append result coll))
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result)
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(defn float? [x]
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"Return True if x is float"
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(isinstance x float))
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(defn symbol? [s]
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"Check whether s is a symbol"
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(instance? HySymbol s))
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(import [threading [Lock]])
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(setv _gensym_counter 1234)
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(setv _gensym_lock (Lock))
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(defn gensym [&optional [g "G"]]
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(setv new_symbol None)
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(global _gensym_counter)
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(global _gensym_lock)
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(.acquire _gensym_lock)
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(try (do (setv _gensym_counter (inc _gensym_counter))
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(setv new_symbol (HySymbol (.format ":{0}_{1}" g _gensym_counter))))
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(finally (.release _gensym_lock)))
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new_symbol)
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(defn calling-module-name [&optional [n 1]]
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"Get the name of the module calling `n` levels up the stack from the
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`calling-module-name` function call (by default, one level up)"
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(import inspect)
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(setv f (get (.stack inspect) (+ n 1) 0))
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(get f.f_globals "__name__"))
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(defn first [coll]
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"Return first item from `coll`"
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(next (iter coll) None))
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(defn identity [x]
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"Returns the argument unchanged"
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x)
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(defn inc [n]
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"Increment n by 1"
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(+ n 1))
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(defn instance? [klass x]
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(isinstance x klass))
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(defn integer [x]
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"Return Hy kind of integer"
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(long-type x))
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(defn integer? [x]
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"Return True if x is an integer"
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(isinstance x (, int long-type)))
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(defn integer-char? [x]
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"Return True if char `x` parses as an integer"
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(try
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(integer? (int x))
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(except [ValueError] False)
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(except [TypeError] False)))
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(defn interleave [&rest seqs]
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"Return an iterable of the first item in each of seqs, then the second etc."
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(chain.from-iterable (zip #* seqs)))
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(defn interpose [item seq]
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"Return an iterable of the elements of seq separated by item"
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(drop 1 (interleave (repeat item) seq)))
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(defn iterable? [x]
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"Return true if x is iterable"
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(isinstance x collections.Iterable))
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(defn iterate [f x]
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(setv val x)
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(while True
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(yield val)
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(setv val (f val))))
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(defn iterator? [x]
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"Return true if x is an iterator"
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(isinstance x collections.Iterator))
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(defn juxt [f &rest fs]
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"Return a function that applies each of the supplied functions to a single
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set of arguments and collects the results into a list."
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(setv fs (cons f fs))
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(fn [&rest args &kwargs kwargs]
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(list-comp (f #* args #** kwargs) [f fs])))
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(defn last [coll]
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"Return last item from `coll`"
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(get (tuple coll) -1))
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(defn list* [hd &rest tl]
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"Return a dotted list construed from the elements of the argument"
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(if (not tl)
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hd
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(cons hd (list* #* tl))))
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(defn macroexpand [form]
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"Return the full macro expansion of form"
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(import hy.macros)
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(setv name (calling-module-name))
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(hy.macros.macroexpand form (HyASTCompiler name)))
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(defn macroexpand-1 [form]
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"Return the single step macro expansion of form"
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(import hy.macros)
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(setv name (calling-module-name))
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(hy.macros.macroexpand-1 form (HyASTCompiler name)))
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(defn merge-with [f &rest maps]
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"Returns a map that consists of the rest of the maps joined onto
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the first. If a key occurs in more than one map, the mapping(s)
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from the latter (left-to-right) will be combined with the mapping in
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the result by calling (f val-in-result val-in-latter)."
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(if (any maps)
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(do
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(defn merge-entry [m e]
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(setv k (get e 0) v (get e 1))
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(if (in k m)
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(assoc m k (f (get m k) v))
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(assoc m k v))
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m)
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(defn merge2 [m1 m2]
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(reduce merge-entry (.items m2) (or m1 {})))
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(reduce merge2 maps))))
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(defn neg? [n]
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"Return true if n is < 0"
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(< n 0))
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(defn none? [x]
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"Return true if x is None"
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(is x None))
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(defn numeric? [x]
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(import numbers)
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(instance? numbers.Number x))
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(defn nth [coll n &optional [default None]]
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"Return nth item in collection or sequence, counting from 0.
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Return None if out of bounds unless specified otherwise."
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(next (drop n coll) default))
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(defn odd? [n]
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"Return true if n is an odd number"
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(= (% n 2) 1))
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(def -sentinel (object))
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(defn partition [coll &optional [n 2] step [fillvalue -sentinel]]
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"Chunks coll into n-tuples (pairs by default). The remainder, if any, is not
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included unless a fillvalue is specified. The step defaults to n, but can be
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more to skip elements, or less for a sliding window with overlap."
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(setv
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step (or step n)
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coll-clones (tee coll n)
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slices (genexpr (islice (get coll-clones start) start None step)
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[start (range n)]))
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(if (is fillvalue -sentinel)
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(zip #* slices)
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(zip-longest #* slices :fillvalue fillvalue)))
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(defn pos? [n]
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"Return true if n is > 0"
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(> n 0))
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(defn rest [coll]
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"Get all the elements of a coll, except the first."
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(drop 1 coll))
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(defn repeatedly [func]
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"Yield result of running func repeatedly"
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(while True
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(yield (func))))
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(defn second [coll]
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"Return second item from `coll`"
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(nth coll 1))
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(defn some [pred coll]
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"Return the first logical true value of (pred x) for any x in coll, else None"
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(first (filter None (map pred coll))))
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(defn string [x]
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"Cast x as current string implementation"
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(if-python2
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(unicode x)
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(str x)))
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(defn string? [x]
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"Return True if x is a string"
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(if-python2
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(isinstance x (, str unicode))
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(isinstance x str)))
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(defn take [count coll]
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"Take `count` elements from `coll`, or the whole set if the total
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number of entries in `coll` is less than `count`."
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(islice coll None count))
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(defn take-nth [n coll]
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"Return every nth member of coll
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raises ValueError for (not (pos? n))"
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(if (not (pos? n))
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(raise (ValueError "n must be positive")))
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(setv citer (iter coll) skip (dec n))
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(for* [val citer]
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(yield val)
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(for* [_ (range skip)]
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(next citer))))
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(defn zero? [n]
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"Return true if n is 0"
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(= n 0))
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(defn read [&optional [from-file sys.stdin]
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[eof ""]]
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"Read from input and returns a tokenized string. Can take a given input buffer
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to read from, and a single byte as EOF (defaults to an empty string)"
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(setv buff "")
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(while True
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(setv inn (string (.readline from-file)))
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(if (= inn eof)
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(raise (EOFError "Reached end of file")))
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(+= buff inn)
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(try
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(setv parsed (first (tokenize buff)))
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(except [e [PrematureEndOfInput IndexError]])
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(else (break))))
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parsed)
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(defn read-str [input]
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"Reads and tokenizes first line of input"
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(read :from-file (StringIO input)))
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(defn hyify [text]
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"Convert text to match hy identifier"
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(.replace (string text) "_" "-"))
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(defn keyword [value]
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"Create a keyword from the given value. Strings numbers and even objects
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with the __name__ magic will work"
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(if (and (string? value) (value.startswith HyKeyword.PREFIX))
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(hyify value)
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(if (string? value)
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(HyKeyword (+ ":" (hyify value)))
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(try
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(hyify (.__name__ value))
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(except [] (HyKeyword (+ ":" (string value))))))))
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(defn name [value]
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"Convert the given value to a string. Keyword special character will be stripped.
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String will be used as is. Even objects with the __name__ magic will work"
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(if (and (string? value) (value.startswith HyKeyword.PREFIX))
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(hyify (cut value 2))
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(if (string? value)
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(hyify value)
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(try
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(hyify (. value __name__))
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(except [] (string value))))))
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(defn xor [a b]
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"Perform exclusive or between two parameters"
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(if (and a b)
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False
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(or a b)))
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(def *exports*
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'[*map accumulate butlast calling-module-name chain coll? combinations
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comp complement compress cons cons? constantly count cycle dec distinct
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disassemble drop drop-last drop-while empty? eval even? every? exec first
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filter flatten float? fraction gensym group-by identity inc input instance?
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integer integer? integer-char? interleave interpose islice iterable?
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iterate iterator? juxt keyword keyword? last list* macroexpand
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macroexpand-1 map merge-with multicombinations name neg? none? nth
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numeric? odd? partition permutations pos? product range read read-str
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remove repeat repeatedly rest reduce second some string string? symbol?
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take take-nth take-while xor tee zero? zip zip-longest])
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