Szathmáry László honlapja @ DEIK

Types that you'll use the most often:

let
a = 42 # int is int64 (8 bytes) on a 64-bit system
pi = 3.14 # float is float64 (8 bytes) on a 64-bit system
s = "nim" # string
ok = true # bool (1 byte)
c = 'x' # char (1 byte)

Integer types:

int        # signed, 64-bit long on a 64-bit system
int8       # 8 bits, i.e. 1-byte long
int16
int32
int64

uint       # unsigned, 64-bit long on a 64-bit system
uint8      # 8 bits, i.e. 1-byte long
uint16
uint32
uint64

Type info #1:

import typetraits # echo n.type.name

proc main() =
let a = 42 # has type int

echo a # 42
echo a.sizeof # 8 (8 bytes in the memory)
echo a.type.name # "int" (as string)
echo a.low # -9223372036854775808 (smallest possible value)
echo a.high # 9223372036854775807 (largest possible value)

echo int.low # -9223372036854775808 (works with types too)
echo int.high # 9223372036854775807 (works with types too)

Type info #2:

let
a = 42
b = true
c = 'A'

echo typeof(a) # int

echo typeof(b) # bool

echo typeof(c) # char

let s: string = $typeof(a)
echo s # "int" as string

Integer literals in various number systems:

let
decimal = 42
hex = 0xffff
octal = 0o644
binary = 0b1111_0101

Type suffixes:

nim> 42'i8
42 == type int8

nim> 42'u8
42 == type uint8

nim> 3.14'f32
3.14 == type float32

nim> 3.14
3.14 == type float64

In C, 3.14 is a double. Here, it's called a float or float64. The type float is a float64 on a 64-bit system.

Char type

Like in C, a char is just 1 byte.

let
a1 = 'A'
a2 = '\x41' # also 'A', given in hexa

special = 'é' # ERROR, it's 2 bytes in UTF-8

ok = "é" # stored as a string

Basic types

Char type