EO+ ANTLR4 Grammar

An ANTLR4 grammar for the EO+ quest scripting language from Endless Online.

Branches

• master: The official EO+ syntax
• eoserv: The EOSERV flavor of the EO+ syntax

Syntax support

The following syntax structures are supported:

• main block
  • questname attribute
  • version attribute
• state block
  • desc statement
  • action statement
  • rule statement
• Expressions
  • String literals
  • Integer literals
• Identifiers
  • of the form [$_a-zA-Z][_a-zA-Z0-9]*

Differences

While simple, the official "grammar" isn't especially well-defined. The quest parser in the official game server was very lenient, and would accept all sorts of malformed inputs.

This grammar disallows:

• Strings that are not properly terminated
• Argument lists that are not properly closed
• Omission of the keywords action or rule
• Mislabeled action and rule statements
• Use of dashes within identifier names

Examples

• See the examples directory for test data files.
• See the eo-quests repo for the official quest files.

License

Licensed under the MIT license.