goidiomatic

README

Go Idiomatic

go_idiomatic provides a Starlark module that defines Go idiomatic functions and values.

Functions

length(obj) int

Returns the length of the object, for string it returns the number of Unicode code points, instead of bytes like len().

Examples

String

Calculate the length of a CJK string.

load("go_idiomatic", "length")
s = "你好"
print(length(s), len(s))
# Output: 2 6

Misc

Calculate the length of a list, set and map.

load("go_idiomatic", "length")
print(length([1, 2, 3]), length(set([1, 2])), length({1: 2}))
# Output: 3 2 1

sum(iterable, start=0)

Returns the sum of start and the items of an iterable from left to right. The iterable's items and the start value are normally numbers.

Examples

Basic

Calculate the sum of a list.

load("go_idiomatic", "sum")
print(sum([1, 2, 3]))
# Output: 6

Start

Calculate the sum of a list with a start value.

load("go_idiomatic", "sum")
print(sum([1, 2, 3], 10))
# Output: 16

distinct(iterable)

Returns an iterable with distinct elements from the given iterable, i.e., without duplicates. For a list and custom types, it returns a new list with distinct elements. For a tuple, it returns a new tuple with distinct elements. For a dict, it returns the keys in a list. For a set, it just returns the original set.

Parameters

name	type	description
iterable	iterable	The iterable to process for distinct elements.

Examples

List

Get distinct elements from a list.

load("go_idiomatic", "distinct")
print(distinct([1, 2, 2, 3, 3, 3]))
# Output: [1, 2, 3]

Tuple

Get distinct elements from a tuple.

load("go_idiomatic", "distinct")
print(distinct((1, 2, 2, 3, 3, 3)))
# Output: (1, 2, 3)

Dict

Get distinct keys from a dictionary.

load("go_idiomatic", "distinct")
print(distinct({1: 'a', 2: 'b', 3: 'c'}))
# Output: [1, 2, 3]

Set

Return original set (already distinct).

load("go_idiomatic", "distinct")
print(distinct(set([1, 2, 3, 3])))
# Output: {1, 2, 3}

hex(x)

Convert an integer number to a lowercase hexadecimal string prefixed with 0x.

Examples

Basic

Convert an integer to a hexadecimal string.

load("go_idiomatic", "hex")
print(hex(255))
# Output: 0xff

Negative

Convert a negative integer to a hexadecimal string.

load("go_idiomatic", "hex")
print(hex(-42))
# Output: -0x2a

oct(x)

Convert an integer number to an octal string prefixed with 0o.

Examples

Basic

Convert an integer to an octal string.

load("go_idiomatic", "oct")
print(oct(255))
# Output: 0o377

Negative

Convert a negative integer to an octal string.

load("go_idiomatic", "oct")
print(oct(-56))
# Output: -0o70

bin(x)

Convert an integer number to a binary string prefixed with 0b.

Examples

Basic

Convert an integer to a binary string.

load("go_idiomatic", "bin")
print(bin(255))
# Output: 0b11111111

Negative

Convert a negative integer to a binary string.

load("go_idiomatic", "bin")
print(bin(-10))
# Output: -0b1010

bytes_hex(bytes,sep="",bytes_per_sep=1)

Return a string containing two hexadecimal digits for each byte in the instance. If you want to make the hex string easier to read, you can specify a single character separator sep parameter to include in the output. By default, this separator will be included between each byte. A second optional bytes_per_sep parameter controls the spacing. Positive values calculate the separator position from the right, negative values from the left.

Parameters

name	type	description
bytes	bytes	The bytes to convert.
sep	string	The separator to use.
bytes_per_sep	int	The number of bytes per separator.

Examples

Basic

Convert bytes to a hexadecimal string.

load("go_idiomatic", "bytes_hex")
print(bytes_hex(b"hello"))
# Output: 68656c6c6f

Separator

Convert bytes to a hexadecimal string with a separator.

load("go_idiomatic", "bytes_hex")
print(bytes_hex(b"hello", sep=":"))
# Output: 68:65:6c:6c:6f

Bytes per separator

Convert bytes to a hexadecimal string with a separator and bytes per separator.

load("go_idiomatic", "bytes_hex")
print(bytes_hex(b"hello", sep=":", bytes_per_sep=2))
# Output: 68:656c:6c6f

sleep(secs)

Sleeps for the given number of seconds.

Examples

Basic

Sleep for 1 second.

load("go_idiomatic", "sleep")
sleep(1)

exit(code=0)

Exits the program with the given exit code.

Examples

Default

Exit with default code (0).

load("go_idiomatic", "exit")
exit()

Non-zero

Exit with code 1.

load("go_idiomatic", "exit")
exit(1)

quit(code=0)

Alias for exit().

Examples

Default

Exit with default code (0).

load("go_idiomatic", "quit")
quit()

Non-zero

Exit with code 1.

load("go_idiomatic", "quit")
quit(1)

module(name, **kv)

Returns the module with the given name and keyword arguments. The main difference between the module and the struct is that the string representation of the module does not enumerate its fields. The module can't be compared with == and !=, but the struct can.

Parameters

name	type	description
name	string	The name of the module to return.
kv	**kwargs	Key-value pairs to provide attributes.

Examples

Basic

Get the os module with pid attribute.

load("go_idiomatic", "module")
os = module("os", pid=1)
print(os)
# Output: <module "os">

struct(**kv)

Returns a new struct with the given keyword arguments.

Parameters

name	type	description
kv	**kwargs	Key-value pairs to provide attributes.

Examples

Basic

Create a struct with name and age attributes.

load("go_idiomatic", "struct")
person = struct(name="Alice", age=30)
print(person)
# Output: struct(age = 30, name = "Alice")

make_struct(name, **kv)

Returns a new struct with the given name as constructor and keyword arguments. Comparing two structs with == and != will compare their constructors first and then their fields.

Parameters

name	type	description
name	string	The name to use as constructor.
kv	**kwargs	Key-value pairs to provide attributes.

Examples

Basic

Create a struct with name and age attributes.

load("go_idiomatic", "make_struct")
person = make_struct("Person", name="Alice", age=30)
print(person)
# Output: Person(age = 30, name = "Alice")

Types

nil

Value as an alias for None.

true

Value as an alias for True.

false

Value as an alias for False.

Documentation

Overview

Package goidiomatic provides a Starlark module that defines Go idiomatic functions and values.

Index

• Constants
• Variables
• func LoadModule() (starlark.StringDict, error)

Constants

const ModuleName = "go_idiomatic"

ModuleName defines the expected name for this Module when used in Starlark's load() function, eg: load('go_idiomatic', 'nil')

Variables

var (
	// ErrSystemExit is returned by exit() to indicate the program should exit.
	ErrSystemExit = errors.New(`starlet runtime system exit (Use Ctrl-D in REPL to exit)`)
)

Functions

func LoadModule

func LoadModule() (starlark.StringDict, error)

LoadModule loads the Go idiomatic module.