tag_value = chat:get_tag(tag_name)

The same as chats:get_tag but the subject of this chat is the default root.

output = chat:replace_tags(input)

The same as chats:replace_tags but the subject of this chat is the default root.

tag_value = chat:set_tag(tag_name,tag_value)

The same as chats:set_tag but the subject of this chat is the default root.

chat:set_tags(tags)

Set all the values in the given table of {tag_name=tag_value} pairs.

chat:set_topic(topic_name)

Set the current topic for this chat object, information about this topic and its gotos are built from and stored in this chat object.

chat.topic_name

Will be set to the given topic name.

We merge all gotos found in this topic and all topic parents by iterating over the dotnames. We only use add each topic once and each topic may have a bit of logic that decides if it should be displayed.

<topic_name?logic_test

So this would goto the topic_name if the logic_test passes. The logic test is written simmilar to a url query after the question mark comes a number of tests that are then & or | together in left to right order (no operator precedence).

<topic_name?count<10&seen==false

So this would display the goto option if count is less than 10 and seen is set to false. These variables we are testing are tag_names and default to the current subject chat but could reference other subjects by explicitly including a root.

Available logic tests are

name==value
name=value

True if the tag is set to this value.

name!=value

True if the tag is not set to this value.

name<value

True if the tag is less than this value (numeric test).

name>value

True if the tag is more than this value (numeric test).

name<=value

True if the tag is less than or equal to this value (numeric test).

name>=value

True if the tag is more than or equal to this value (numeric test).

All of these tests can be preceded by a ! to negate them so

name!=vale
!name==value

Are both a test for inequality.

Multiple tests can be joined together by & (and) or | (or) this logic will be applied to a running total moving from left to right as the values are evaluated with the final value deciding if this goto will be displayed.