Nim en ejemplos (1)

 

En post pasados vimos que el lenguaje de programación Nim (o Nimrod Lang) es bastante parecido a Python.

#Tipos de datos en Nim Lang

var numero:int = 45
var str:string = "ABC"
var flotante:float = 45.0
const VERDADERO = true


if VERDADERO:
  echo "Numero: ",numero
  echo "Cadena: ",str
  echo "Flotante: ",flotante

Salvo algunas diferencias, Nim es un hermano siámes de Python.
Ejemplo. Obtener el número binario de un número decimal:

import strutils

var decimal:int = 144
var binario:string=""
var residuo:int=0
echo "Decimal: ",decimal
while decimal >=2:
   residuo = decimal mod 2
   decimal = parseint(intToStr((int) decimal/2))
   binario &=""&intToStr(residuo)
   
binario &=""&intToStr(decimal)
var tam = len(binario) - 1
var temp:string = binario
binario=""
while tam >= 0:
   binario &=""&temp[tam]
   tam -=1
echo "Binario: ",decimal

En Python, vemos que no cambia mucho:

decimal = 144
residuo = 0
binario = ""
print("Decimal:",decimal)
while decimal >= 2:
    residuo = decimal%2
    decimal = int(decimal/2)
    binario += str(residuo)

binario += str(decimal)
print(binario)
i = len(binario)-1
temp = binario
binario = ""

while i >= 0:
    print("i:",i)
    binario += temp[i]
    i-=1
    
print("Binario:",binario)

Nim podría ser muy fácil para quienes ya saben Python. Incluso para quienes usan Ruby o Crystal. Veamos unos ejemplos sacados de la página oficial de Nim.
Condicionales

var conditional = 42

if conditional < 0:
  echo "conditional < 0"
elif conditional > 0:
  echo "conditional > 0"
else:
  echo "conditional == 0"

var ternary = if conditional == 42: true else: false

var another =
  if conditional == 0:
    "zero"
  elif conditional mod 2 == 0:
    "even"
  else:
    "odd"


# Case switch.
var letter = 'c'

case letter
of 'a':
  echo "letter is 'a'"
of 'b', 'c':
  echo "letter is 'b' or 'c'"
of 'd'..'h':
  echo "letter is between 'd' and 'h'"
else:
  echo "letter is another character"

Matemática básica

import math

# Basic math.
assert 1 + 2 == 3        # Sum
assert 4 - 1 == 3        # Substraction
assert 2 * 2 == 4        # Multiplication
assert 4 / 2 == 2.0      # Division
assert 4 div 2 == 2      # Integer Division
assert 2 ^ 3 == 8        # Power
assert 4 mod 2 == 0      # Modulo
assert (2 xor 4) == 6    # XOR
assert (4 shr 2) == 1    # Shift Right
assert PI * 2 == TAU     # PI and TAU
assert sqrt(4.0) == 2.0  # Square Root
assert round(3.5) == 4.0 # Round
assert isPowerOfTwo(16)  # Powers of Two
assert floor(2.9) == 2.0 # Floor
assert ceil(2.9) == 3.0  # Ceil
assert cos(TAU) == 1.0   # Cosine
assert gcd(12, 8) == 4   # Greatest common divisor
assert trunc(1.75) == 1.0     # Truncate
assert floorMod(8, 3) == 2    # Floor Modulo
assert floorDiv(8, 3) == 2    # Floor Division
assert hypot(4.0, 3.0) == 5.0 # Hypotenuse
assert gamma(4.0) == 6.0      # Gamma function
assert radToDeg(TAU) == 360.0 # Radians to Degrees
assert clamp(1.4, 0.0, 1.0) == 1.0 # Clamp

Cadenas

import strutils

assert "con" & "cat" == "concat"
assert "    a    ".strip == "a"
assert "42".parseInt == 42
assert "3.14".parseFloat == 3.14
assert "0x666".parseHexInt == 1638
assert "TrUe".parseBool == true
assert "0o777".parseOctInt == 511
assert "a".repeat(9) == "aaaaaaaaa"
assert "abc".startsWith("ab")
assert "abc".endsWith("bc")
assert ["a", "b", "c"].join == "abc"
assert "abcd".find("c") == 2
assert "a x a y a z".count("a") == 3
assert "A__B__C".normalize == "abc"
assert "a,b".split(",") == @["a", "b"]
assert "a".center(5) == "  a  "
assert "a".indent(4) == "    a"
assert "    a".unindent(4) == "a"

for word in tokenize("This is an example"):
  echo word

Básico

import strformat

type
  Person = object
    name: string
    age: Natural # Ensures the age is positive

let people = [
  Person(name: "John", age: 45),
  Person(name: "Kate", age: 30)
]

for person in people:
  # Type-safe string interpolation,
  # evaluated at compile time.
  echo(fmt"{person.name} is {person.age} years old")


# Thanks to Nim's 'iterator' and 'yield' constructs,
# iterators are as easy to write as ordinary
# functions. They are compiled to inline loops.
iterator oddNumbers[Idx, T](a: array[Idx, T]): T =
  for x in a:
    if x mod 2 == 1:
      yield x

for odd in oddNumbers([3, 6, 9, 12, 15, 18]):
  echo odd


# Use Nim's macro system to transform a dense
# data-centric description of x86 instructions
# into lookup tables that are used by
# assemblers and JITs.
import macros, strutils

macro toLookupTable(data: static[string]): untyped =
  result = newTree(nnkBracket)
  for w in data.split(';'):
    result.add newLit(w)

const
  data = "mov;btc;cli;xor"
  opcodes = toLookupTable(data)

for o in opcodes:
  echo o

Ejemplo. El clásico Hola, mundo en Nim.
holamundo.nim

echo("Hola, mundo en Nim Language!!")

Compilar y ejecutar:

$ nim c -r holamundo.nim

Más ejemplos en próximos post.

Enlaces:
https://dev.to/aachh/nim-v-rust-4kh5
https://dev.to/itachiuchiha/getting-started-nim-lang-3g5b
http://rosettacode.org/wiki/Category:Nim
https://nim-lang.org/
http://alquimistadecodigo.blogspot.com/2020/08/nim-un-lenguaje-parecido-python.html
http://alquimistadecodigo.blogspot.com/2020/08/nim-nimrod-language.html