Glastis / lua-must-have-functions

Lua must have functions

Bundle of functions that are useful in many cases.

Json

Got here, https://gist.github.com/tylerneylon/59f4bcf316be525b30ab

Used to convert a json string to a table or a table to string.

local json = require 'json'

json.parse(my_string) -- will return a table containing all objects
json.stringify(my_table) -- will return a printable string

Utilities

Use this by adding local utilities = require 'utilities'.

Trim

Remove spaces from string (before first and after last word)

utilities.trim(str)

Get elem in table

Return the index of the first elem found in array.

utilities.get_elem_in_table(table, elem)

Concatenate arrays

Concatenate two arrays, add t2 elems after t1 ones, at same depth.

local t1 = {1, 2}
local t2 = {3, 4}

utilities.concatenate_arrays(t1, t2) -- return {1, 2, 3, 4}

Split

Split a string into a table of elements, in a same way as bash awk or php explode.

local str = 'Hello world'
local separator = ' '

utilities.split(str, separator) -- return {'Hello', 'world'} 

Exec function table

Execute a table of functions with parameters provided. Params must have the same index that actions, params can be nil.

Arguments:

• actions table (eg: actions[1] = print).
• args table (eg: args[1] = "Hello world"), can be nil, and can contain nil elems.

local actions = {print, print}
local param = {'glastis > guigur', 'Hi'}

utilities.exec_function_table(actions, param) -- will print 'glastis > guigur' and 'Hi'
utilities.exec_function_table_revert(actions, param) -- will print 'Hi' and 'glastis > guigur' 

Debug info

Write calltrace into a log file, with a custom text to see which debug_info function is called.

Arguments:

• more string (eg: "in buggy_function main loop"), can be nil.
• calltrace boolean, if true will write the calltrace to the file.

local more = 'We are inside buggy_function, with parametter test, before the infinite loop'
local calltrace = true

utilities.debug_info(more, calltrace)

Var dump

Like the php var_dump, it returns a variable (table, number, string...) in string.

Arguments:

• var variable to be dumped.
• printval boolean, if the dump should be printed, can be nil.
• max_depth integer, if provided, limit the exploration of sub-tables (in case of recursive or huge tables).
• cur_depth used by var_dump itself, leave it nil.

local var = {1, 'DooM', {'asdasd'}}

utilities.var_dump(var, true)

Round

Args:

• number number to round.
• decimals amount of digits after the decimal point.
• ext_abs if true, 0.5 will be rounded to 1, otherwise, it will be rounded to 0.

local numer = 1.1234
local decimals = 2
local ext_abs = true

utilities.round(number, decimals) -- return 1.12
utilities.round(number, decimals, ext_abs) -- return 1.12

File

Use this by adding local file = require 'file'.

Is existing

Return true if file exists, false otherwise.

local filepath = '/home/glastis/foo.txt'

file.is_existing(filepath)

Read

Read and return all file content.

local filepath = '/home/glastis/foo.txt'

file.read(filepath)

Write

Write and string in file

Args:

• filepath string, path to file, eg: /home/glastis/foo.txt
• str string, content to write
• mode string, "a" to append, "w" to overwrite file or "w+" to delete and write to file. Default is "a".

file.write(filepath, str, mode)

Read line

Read and return one line from a file

Args:

• filepath string, path to file, eg: /home/glastis/foo.txt
• file file, if nil, will open filepath.

local file, line = file.read_line('/home/glastis/foo.txt')

while file do
    print(line)
    file, line = file.read_line('/home/glastis/foo.txt')
end