This section will have a look at effects, how they are created and handled during the play and how to add new effects.

Overview of effects system

Effects can be understood as on-going statuses that have an effect to an character. Good example would be poisoning. When character has poison effect active, he periodically takes small amount of damage, until the effect is removed or it expires.

Both items and characters can cause effects. Spider can cause poisoning and healing potion can grant healing.

Effect handles

pyherc.data.effects.effect.EffectHandle are sort of prototypes for effects. They contain information on when to trigger the effect, name of the effect, possible overriding parameters and amount of charges.


pyherc.data.effects.effect.Effect is a baseclass for all effects. All effects have duration, frequency and tick. Duration tells how long it takes until effect naturally expires. Frequency tells how often effect is triggered and tick is internal counter which keeps track when effect should trigger.

When creating a new effect, subclass Effect class and define method:

def do_trigger(self):

Do trigger method is automatically triggered when effect’s internal counter reaches zero. After the method has been executed, counter will be reset if the effect has not been expired.

Creating Effects

Effects are cread by pyherc.generators.effects.create_effect(). It takes configuration that defines effects and named arguments that are effect specific to create an effect.

EffectsFactory is configured during the start up of the system with information that links names of effects to concrete Effect subclasses and their parameters.

from pyherc.generators import create_effect, get_effect_creator
from pyherc.data.effects import Poison
from pyherc.test.cutesy import Adventurer
from pyherc.rules import Dying

effect_creator = get_effect_creator({'minor poison': {'type': Poison,
                                                      'duration': 240,
                                                      'frequency': 60,
                                                      'tick': 60,
                                                      'damage': 1,
                                                      'icon': 101,
                                                      'title': 'Minor poison',
                                                      'description': 'Causes minor amount of damage'}})

Pete = Adventurer()
print('Hit points before poisoning: {0}'.format(Pete.hit_points))

poisoning = effect_creator('minor poison', target = Pete)

print('Hit points after poisoning: {0}'.format(Pete.hit_points))

Pete the adventurer gets affected by minor poison and as a result loses 1 hit point.

Hit points before poisoning: 10
Hit points after poisoning: 9

Note how the effect factory has been supplied by a dictionary of parameters. These are matched to the constructor of class specified by ‘type’ key. All parameters that are present in the constructor, but are not present in the dictionary needs to be supplied when effect factory creates a new effect instance. In our example there was only single parameter like this, the target of poisoning.

It is also possible to supply parameters during call that have been specified in the dictionary. These parameters are then used to override the default ones.

Effects collection

pyherc.data.effects.effectscollection.EffectsCollection is tasked to keep track of effects and effect handles for particular object. Both Item and Character objects use it to interact with effects sub system.

Following example creates an EffectHandle and adds it to the collection.

from pyherc.data.effects import EffectsCollection,EffectHandle

collection = EffectsCollection()
handle = EffectHandle(trigger = 'on kick',
                      effect = 'explosion',
                      parameters = None,
                      charges = 1)


The collection now contains a single EffectHandle object.

[<pyherc.data.effects.effect.EffectHandle object at 0x...>]

Following example creates an Effect and adds it to the collection.

from pyherc.data.effects import EffectsCollection, Poison

collection = EffectsCollection()
effect = Poison(duration = 200,
                frequency = 10,
                tick = 0,
                damage = 1,
                target = None,
                icon = 101,
                title = 'minor poison',
                description = 'Causes small amount of damage')


The collection now contains a single Poison object.

[<pyherc.data.effects.poison.Poison object at 0x...>]