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  • +add
  • +dec
  • +div
  • +dvr
  • +gte
  • +gth
  • +lte
  • +lth
  • +max
  • +min
  • +mod
  • +mul
  • +sub
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  1. Hoon
  2. Standard Library

1a: Basic Arithmetic

+add

Add

Produces the sum of a and b.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  add
  ~/  %add
  |=  [a=@ b=@]
  ^-  @
  ?:  =(0 a)  b
  $(a (dec a), b +(b))

Examples

> (add 2 2)
4
> (add 1 1.000.000)
1.000.001
> (add 1.333 (mul 2 2))
1.337
> (add 'a' 4)
101
> (add 'a' 'b')
195
> (add 0xc 0xf)
27
> `@ux`(add 0xc 0xf)
0x1b

+dec

Decrement

Decrements a by 1.

Accepts

a is an atom.

Produces

An atom.

Source

++  dec
  ~/  %dec
  |=  a=@
  ~_  leaf+"decrement-underflow"
  ?<  =(0 a)
  =+  b=0
  |-  ^-  @
  ?:  =(a +(b))  b
  $(b +(b))

Examples

> (dec 7)
6
> (dec 0)
! decrement-underflow
! exit
> (dec 'b')
97
> `@t`(dec 'b')
'a'
> (dec 0xc)
11
> `@ux`(dec 0xc)
0xb

+div

Divide

Computes a divided by b without remainder.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  div
  ~/  %div
  |:  [a=`@`1 b=`@`1]
  ^-  @
  -:(dvr a b)

Examples

> (div 4 2)
2
> (div 17 8)
2
> (div 20 30)
0
> (div 'ab' 'a')
259
> `@`'ab'
25.185
> `@`a
97
> (div 0x9f 0x29)
6

+dvr

Divide with remainder

Computes a divided by b, producing the quotient and the remainder.

Accepts

a is an atom.

b is an atom.

Produces

A cell of atoms.

Source

++  dvr
  |:  [a=`@`1 b=`@`1]
  ^-  [p=@ q=@]
  ~_  leaf+"divide-by-zero"
  ?<  =(0 b)
  =+  c=0
  |-
  ?:  (lth a b)  [c a]
  $(a (sub a b), c +(c))

Examples

> (dvr 17 8)
[p=2 q=1]
> (dvr 17 6)
[p=2 q=5]
> (dvr 18 6)
[p=3 q=0]
> (dvr 4 2)
[p=2 q=0]
> (dvr 'ab 'a')
[p=259 q=62]
> `@`'a'
97
> `@`'ab'
25.185

+gte

Greater-than/equal

Tests whether a is greater than or equal to b.

Accepts

a is an atom.

b is an atom.

Produces

A flag.

Source

++  gte
  ~/  %gte
  |=  [a=@ b=@]
  ^-  ?
  !(lth a b)

Examples

> (gte 100 10)
%.y
> (gte 4 4)
%.y
> (gte 3 4)
%.n

+gth

Greater-than

Tests whether a is greater than b.

Accepts

a is an atom.

b is an atom.

Produces

A flag.

Source

++  gth
  ~/  %gth
  |=  [a=@ b=@]
  ^-  ?
  !(lte a b)

Examples

> (gth 'd' 'c')
%.y
> (gth ~h1 ~m61)
%.n
> (gth 'steak' 'brisket')
%.n

+lte

Less-than/equal

Tests whether a is less than or equal to b.

Accepts

a is an atom.

b is an atom.

Produces

A flag.

Source

++  lte
  ~/  %lte
  |=  [a=@ b=@]
  |(=(a b) (lth a b))

Examples

> (lte 4 5)
%.y
> (lte 5 4)
%.n
> (lte 5 5)
%.y
> (lte 0 0)
%.y
> (lte 'a' 'b')
%.y
> `@`'a'
97
> `@`'b'
98
> (lte 'abraham' 'bob')
%.n
> (lte ~m61 ~h1)
%.n

+lth

Less-than

Tests whether a is less than b.

Accepts

a is an atom.

b is an atom.

Produces

A flag.

Source

++  lth
  ~/  %lth
  |=  [a=@ b=@]
  ^-  ?
  ?&  !=(a b)
      |-
      ?|  =(0 a)
          ?&  !=(0 b)
              $(a (dec a), b (dec b))
  ==  ==  ==

Examples

> (lth 4 5)
%.y
> (lth 5 4)
%.n
> (lth 5 5)
%.n
> (lth 5 0)
%.n
> (lth 'a' 'b')
%.y
> `@`'a'
97
> `@`'b'
98
> (lth 'abraham' 'bob')
%.n

+max

Maximum

Computes the greater of a and b.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  max
  ~/  %max
  |=  [a=@ b=@]
  ^-  @
  ?:  (gth a b)  a
  b

Examples

> (max 10 100)
100
> (max 10.443 9)
10.443
> (max 1 1)
1
> (max 'abraham' 'bob')
30.787.873.400.840.801
> `@t`(max 'abraham' 'bob')
'abraham'
> `@t`(max 'abraham' 'benjamin')
'benjamin'
> `@dr`(max ~m6 ~h1)
~h1
>`@ux`(max 0xe1 0x1e)
0xe1

+min

Minimum

Computes the lesser of a and b.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  min
  ~/  %min
  |=  [a=@ b=@]
  ^-  @
  ?:  (lth a b)  a
  b

Examples

> (min 10 100)
10
> (min 10.443 9)
9
> (min 1 1)
1
> (min 'abraham' 'bob')
6.451.042
> `@t`(min 'abraham' 'bob')
'bob'
> `@t`(min 'abraham' 'benjamin')
'abraham'
> `@dr`(min ~m6 ~h1)
~m6

+mod

Modulus

Computes the remainder of dividing a by b.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  mod
  ~/  %mod
  |:  [a=`@`1 b=`@`1]
  ^-  @
  +:(dvr a b)

Examples

> (mod 5 2)
1
> (mod 5 5)
0
> (mod 2 5)
2
> (mod 40 20)
0
> `@`'c'
99
>`@`'a'
97
> (mod 'c' 'a')
2

+mul

Multiply

Multiplies a by b.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  mul
  ~/  %mul
  |:  [a=`@`1 b=`@`1]
  ^-  @
  =+  c=0
  |-
  ?:  =(0 a)  c
  $(a (dec a), c (add b c))

Examples

> (mul 3 4)
12
> (mul 0 1)
0
> `@`'a'
97
> `@`'b'
98
> (mul 'a' 'b')
9.506
>`@ux`(mul 0x1f 0xe)
0x1b2

+sub

Subtract

Subtracts b from a.

Accepts

a is an atom.

b is an atom.

Produces

An atom.

Source

++  sub
  ~/  %sub
  |=  [a=@ b=@]
  ~_  leaf+"subtract-underflow"
  ^-  @
  ?:  =(0 b)  a
  $(a (dec a), b (dec b))

Examples

> (sub 10 5)
5
> (sub 243 44)
199
> (sub 5 0)
5
> (sub 0 5)
! subtract-underflow
! exit
> (sub 'c' 'a')
2
> `@`'c'
99
> `@`'a'
97
> (sub 0x1f 0xe)
17
> `@ux`(sub 0x1f 0xe)
0x11
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