Control Flow

Control-flow commands take blocks — groups of sub-commands in parentheses — and run them conditionally or repeatedly.

Conditionals

if takes a condition, a then-block, and an optional second block that runs when the condition is false. There is no else keyword:

load token

set $balance @token:balance(DAI @me)
if @bool($balance > 0) (
  print "Has balance"
) (
  print "No balance"
)

Loops

Loop over an array with loop $var of:

loop $item of @arr(0 10) (
  print $item
)

Or repeat until a condition becomes true:

set $i 0
loop until @bool($i >= 5) (
  print $i
  set $i @num($i + 1)
)

User-Defined Commands and Helpers

Use def to define reusable commands and helpers:

# Define a helper — the body is a single expression, not a block
def @double "$x: number -> number" @num($x * 2)

# Define a command — params live in the signature string, the body is a block
def transfer "$token: address $to: address $amount: number" (
  exec $token "transfer(address,uint256)" $to $amount
)

# Use them
set $result @double(21)
transfer @token(DAI) 0x4F2083f5fBede34C2714aFfb3105539775f7FE64 100e18

Groups of defs can be bundled into an inline module with def module <name> ( ...defs ) — see Modules & Imports.

Next Steps

• Blocks & Batching — how blocks work and atomic execution
• Values & Variables — the expressions that drive conditions