Data\Expression
- Value
- Divide
- Multiply
- Subtract
- Add
- Compare
- Logic Not
- Logic And
- Logic Or
- Named Expression
- Exponent
- Modulo
- If

Data\Expression

Expressions are a powerful feature of the DreamEditor that allows you to write formulas and plug them into various fields of game data. They're useful for creating things like damage formulas, where certain weapon types (fire, nature, armored) will deal more or less damage to different "armor" types (water, earth, light) as arbitrarily defined with tags. See notion guide "Using Expressions."
Similar to Validators, expressions are evaluated and return a result. Expressions are more flexible as they can be configured to write user defined formulas, and unlike validators they can return numeric or boolean values depending on context.
In numeric cases, true is treated as 1 and false is treated as 0. In boolean cases, non-zero numbers are treated as true and 0 is treated as false. Note that expressions can also be used as validators.
The most common use case for expressions are for creating custom damage formulas, such as damage = ([caster]STRENGTH * 10) - [target]ARMOR), where STRENGTH and ARMOR are arbitrary attributes defined as tags.
Supported Fields
Expressions can be plugged into a number of existing data fields and can also be used with data binding in custom UI. These are the currently supported data fields:

Behavior/PeriodicInterval
Effect/ApplyBehavior/Duration
Effect/Damage/DamageAmount
Effect/EnumerateUnitList/StepCount
Effect/Heal/HealAmount
Effect/ModifyUnit/ModifyMana/Amount
Effect/ModifyUnit/ModifyShield/Amount
Mover/Orbiting/Radius
As of version 0.10.x and up, Effects now have a universal field expression section where you can overwrite any numeric effect field with an expression by specifying its field path. The expression will be evaluated right before the effect is cast using the same caster/source/target info as passed to the effect itself.

Value

These are the types of values you can include or reference in expression formulas.

Constant

Returns a constant value.

Bool Value

Returns true or false.

Int32 Value

Returns an integer value.

Double Value

Returns a floating point number (with decimal).

Random

Returns a random number between the min and max value.

Int32 Value

MessageType: RangeInt

Returns an integer value.

Double Value

MessageType: RangeDouble

Returns a floating point number (with decimal).

Damage Amount

The damage amount is multiplied by this value (default 0).

Returns the literal damage value when used within a damage effect.

Multiplier

Heal Amount

The heal amount is multiplied by this value (default 0).

Returns the literal heal value when used within a heal effect.

Multiplier

Tag Count

Returns the tag count of a specific tag on a unit.

Unit

EnumType: ValidatorExpressions.UnitLocation

Which unit is evaluated.

Tag Name

Which tag is evaluated.

Unit Level

Returns the level of a unit. Currently limited in usefulness.

Unit

EnumType: ValidatorExpressions.UnitLocation

Which unit is evaluated.

Ability Level

Returns the level of an ability. Currently limited in usefulness.

Ability

Which ablity is evaluated.

Wildsky Upgrade Level [Wild Sky]

Returns the level of a wild sky upgrade.

Data Upgrade

Which upgrade is evaluated.

Upgrade Level

Returns the level of an upgrade.

Upgrade

Which upgrade is evaluated.

Remaining Path Distance

Returns the remaining path distance for a unit with waypoints.

Unit

EnumType: ValidatorExpressions.UnitLocation

Which unit is evaluated.

Unit Ability Cooldown

Returns the current cooldown remaining for an ability.

Unit

EnumType: ValidatorExpressions.UnitLocation

Which unit is evaluated.

Ability

Which ablity is evaluated.

Returns the elapsed time that a behavior has been on a unit.

Note that this duration is reset to 0 when the stack count is refreshed.

Unit

EnumType: ValidatorExpressions.UnitLocation

Which unit is evaluated.

Behavior

Which behavior is evaluated.

Behavior Duration

Returns the duration that a behavior has been on a unit.

Returns the maximum duration of a behavior on a unit. Note that this duration is not extended when the stack count is refreshed.

Unit

EnumType: ValidatorExpressions.UnitLocation

Which unit is evaluated.

Behavior

Which behavior is evaluated.

Add Expressions

Returns the sum of the listed expressions.

Functionally similar to Add but used as an expression value rather than a top-level operator.

Effect Critical Hit

Returns 1 if the effect tree is the result of a critical hit with a weapon or ability.
This can be used to create damage expressions that deal increased damage on critical hits. For example this psuedo-expression would cause a damage effect to deal 150% damage on critical hit.

Multiply( EffectCrticial * DamageAmount(1) * Constant(0.5) )

Swap out the constant for value derived from tag count) to support dynamic critical hit damage multipliers.

Units Distance

Returns the distance between units.

From Unit

EnumType: ValidatorExpressions.UnitLocation

To Unit

EnumType: ValidatorExpressions.UnitLocation

Divide

Divide a value by another.

Multiply

Multiply multiple values together. Supports nested expressions.

Subtract

Subtract a value from another.

Add

Add multiple values together. Supports nested expressions.

Compare

Compares two values/expressions and returns true or false based on the result.

Logic Not

Returns the flipped value or expression (true becomes false, false becomes true).

Logic And

Returns true if all listed values/expressions are true.

Logic Or

Returns true if any listed values/expressions are true.

Named Expression

Used to reference another expression. This is useful for combining multiple expressions or breaking complex expressions into smaller abstractions.

Exponent

Returns value to the power of another. Similar to the ^ operator in Lua.

Modulo

Returns the remainder of a value after being divided by another. Similar to the % operator in Lua.

If

Returns the sum of the Values expressions if the Compare condition returns true. Otherwise returns the same of the Else Values expressions.