A brief introduction

Once Funcml has been installed on your system, you can start generating complex files. Take, for example, the following file (extension .yf (YAML function)):

sum_values:
  _sum: [1, 2, 3]

This file only contains valid YAML syntax. It can also be written as:

sum_values:
  _sum:
    - 1
    - 2
    - 3

And since YAML syntax also support one-liners, this syntax is also tolerated.

sum_values: { _sum: [1, 2, 3] }

Here, we want the key sum_values to be equal to 6.

Let me introduce to you the first function of Funcml, _sum. As describe in its dedicated documentation section, this function takes an array of integers as argument and mutates the calling block from a dictionary to the direct result. It mutates__ the calling block, keep this sentence in your head as this is the core principle of Funcml. Funcml _mutates structured blocks from YAML or JSON.

Variables

YAML already implements a principle of anchor ; the syntax isn’t that easy to memorize and the feature is pretty limited in fact. Funcml prefers to provide an alternative that’ll be handled by a mutation. A Funcml variable is a string, always starting with a dollar-sign, like in PHP or Javascript for example.

variable: "string"
my_value: "$variable"

The my_value key will be equal to “string” as the $variable will be expanded. What is nice here is that the dot-convention also works:

variable:
  sub_variable:
    again: "string"

my_value: "$variable.sub_variable.again"

The variable can also be expanded to another data type. For example, from a string to a dictionary:

variable:
  sub_variable:
    again:
      sub_key: sub_value

my_value: "$variable.sub_variable.again"

will be rendered as

my_value:
  sub_key: sub_value

And last but not the least, the mutations are recursive, meaning you can use any function in the called key.

variable:
  sub_variable:
    again:
      sub_key:
        _sum:
          - 1
          - 2
          - 3

my_value: "$variable.sub_variable.again"

will be rendered as:

my_value:
  sub_key: 6

What you need to take attention to is that a block always returns its mutated value. So Funcml acts as it:

• first, it process the _sum function with parameters 1, 2 and 3.
• $.variable.sub_variable.again.sub_key is returned as 6.
• Finally the variable call on my_value is executed.

Special variables

Sometimes, you just want your computer to return a value you don’t know yet. For example, the current time as a string or a UUID. To make it short, some special variables exist in Funcml:

$now returns the current date
$uuidv4 returns a new UUIDv4

Want to learn more about the usable functions ? Read the dedicated page on this website.