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name: ordo-expression-syntax description: Ordo expression syntax quick reference. Includes comparison operators, logical operators, built-in functions, conditional expressions, field access syntax. Use for writing rule conditions, calculating output values, data transformation.

Ordo Expression Syntax

Operators

Comparison Operators

Operator	Description	Example
==	Equal	status == "active"
!=	Not equal	status != "banned"
>	Greater than	age > 18
>=	Greater or equal	balance >= 1000
<	Less than	price < 100
<=	Less or equal	level <= 5

Logical Operators

Operator	Description	Example
&&	And	age >= 18 && active == true
||	Or	vip == true || points > 1000
!	Not	!is_blocked

Arithmetic Operators

Operator	Description	Example
+	Addition	price + tax
-	Subtraction	total - discount
*	Multiplication	quantity * price
/	Division	total / count
%	Modulo	index % 2

Field Access

Dot Notation

user.name
user.profile.level
order.items[0].price

Array Indexing

items[0]
matrix[1][2]
users[index]

Safe Access (coalesce)

coalesce(user.nickname, user.name, "Anonymous")

Built-in Functions

String Functions

Function	Description	Example
len(s)	String length	len(name) > 0
upper(s)	To uppercase	upper(code) == "VIP"
lower(s)	To lowercase	lower(email)
trim(s)	Trim whitespace	trim(input)
starts_with(s, prefix)	Prefix match	starts_with(url, "https")
ends_with(s, suffix)	Suffix match	ends_with(file, ".pdf")
contains_str(s, sub)	Contains substring	contains_str(desc, "urgent")
substring(s, start, end)	Extract substring	substring(code, 0, 3)

Math Functions

Function	Description	Example
abs(n)	Absolute value	abs(diff) < 0.01
min(a, b, ...)	Minimum	min(price, max_price)
max(a, b, ...)	Maximum	max(0, balance)
floor(n)	Floor	floor(rating)
ceil(n)	Ceiling	ceil(price)
round(n)	Round	round(average)

Array Functions

Function	Description	Example
len(arr)	Array length	len(items) > 0
sum(arr)	Sum of array	sum(prices) >= 100
avg(arr)	Average	avg(scores) > 60
count(arr)	Element count	count(orders)
first(arr)	First element	first(results)
last(arr)	Last element	last(history)

Type Functions

Function	Description	Example
type(v)	Get type	type(value) == "string"
is_null(v)	Is null	is_null(optional)
is_number(v)	Is number	is_number(input)
is_string(v)	Is string	is_string(data)
is_array(v)	Is array	is_array(items)

Conversion Functions

Function	Description	Example
to_int(v)	To integer	to_int(str_num)
to_float(v)	To float	to_float(price)
to_string(v)	To string	to_string(code)

Time Functions

Function	Description	Example
now()	Current timestamp (seconds)	now() - created_at > 86400
now_millis()	Current timestamp (milliseconds)	now_millis()

Conditional Expressions

if-then-else

if condition then value1 else value2

Examples:

if exists(discount) then price * (1 - discount) else price
if vip == true then 0.2 else 0.05
if age >= 18 then "adult" else "minor"

exists Check

if exists(user.nickname) then user.nickname else user.name

Nested Conditions

if tier == "gold" then 0.2
else if tier == "silver" then 0.1
else 0.05

Literals

Numbers

42          # Integer
3.14        # Float
-100        # Negative

Strings

"hello"
"it's ok"
"line1\nline2"

Booleans

true
false

Null

null

Rust API

Parsing Expressions

use ordo_core::prelude::*;

let parser = ExprParser::new();
let expr = parser.parse("age >= 18 && status == \"active\"")?;

Evaluation

let evaluator = Evaluator::new();
let context = Context::from_json(r#"{"age": 25, "status": "active"}"#)?;
let result = evaluator.eval(&expr, &context)?;

Compile to Bytecode

let compiler = ExprCompiler::new();
let compiled = compiler.compile(&expr)?;
let vm = BytecodeVM::new();
let result = vm.execute(&compiled, &context)?;

Key Files

• crates/ordo-core/src/expr/parser.rs - Expression parser
• crates/ordo-core/src/expr/eval.rs - Expression evaluation
• crates/ordo-core/src/expr/functions.rs - Built-in functions
• crates/ordo-core/src/expr/ast.rs - AST definitions