Eclipse-based IDE for the Fantom Programming Language

F4 is the full-featured Integrated Development Environment for emerging Fantom programming language. This is a first self-hosted Eclipse-based IDE we know, fully developed without a line of Java code.

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Type inference for proposals inside it-blocks, collection elements, Java classes and methods available via FFI.


Breakpoints, variables introspection and modification, stepping, mixed Fantom and Java stack frames.


Search for code elements, references to elements including read and/or write references to fields.


Go to declaration, open type, class hierarchy, call hierarchy, source and project outlines, in-place navigation.