Coding Style

Indentation

Coco uses Python-style indentation to define code hierarchy. A colon (:) at the end of a line indicates that an indented block follows.

// Standard Block (Recommended: 4 spaces)
if x > 5:
    throw "Too much"
else:
    emit "Phew"

// One-Liner (Allowed for single statements)
if x > 5: throw "Too much"
else: emit "Phew"

Key Rules

• Consistency — All lines in a block must use the exact same number of spaces
• Tabs vs Spaces — A TAB counts as 1 space. Use spaces only and never mix tabs and spaces

Multiple Lines

Long statements can span multiple lines for better readability:

function NameSupply(
    n String,
    s U256,
) -> (name String,
      supply U256):
    return(name: n,
           supply: s)

Lines may continue wherever a space could be written. Strings can span multiple lines, but indentation is included in the string:

s = "My spl
it string"      // Result: "My split string"

s = "My spl
    it string"  // Result: "My spl    it string"

Comments

Coco supports line comments with //. Multi-line comments require // on each line:

// Multi-line comments need
// a // sign in front of
// each line
x = 5  // inline comment

Unit Test Directives

Special comment prefixes // > and // < are used for testing. They are ignored by the compiler but processed by coco test.

Naming Conventions

Element	Convention	Example
File name	snake_case	my_logic.coco
Module name	PascalCase	MyLogic
Package name	snake_case	my_package
Endpoints/Functions	PascalCase	GetBalance
Classes & Events	PascalCase	TokenInfo
Class methods	snake_case	get_value
Variables & Arguments	snake_case	user_balance
State & Field names	snake_case	total_supply
Constants	ALL_CAPS	MAX_SUPPLY