Block-Based Syntax from Context-Free Grammars

Mauricio Verano Merino, Tijs van der Storm

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

4 Citations (Scopus)


Block-based programming systems employ a jigsaw metaphor to write programs. They are popular in the domain of programming education (e.g., Scratch), but also used as a programming interface for end-users in other disciplines, such as arts, robotics, and configuration management. In particular, block-based environments promise a convenient interface for Domain-Specific Languages (DSLs) for domain experts who might lack a traditional programming education. However, building a block-based environment for a DSL from scratch requires significant effort.
This paper presents an approach to engineer block-based language interfaces by reusing existing language artifacts. We present Kogi, a tool for deriving block-based environments from context-free grammars. We identify and define the abstract structure for describing block-based environments. Kogi transforms a context-free grammar into this structure, which then generates a block-based environment based on Google Blockly. The approach is illustrated with four case studies, a DSL for state machines, Sonification Blocks (a DSL for sound synthesis), Pico (a simple programming language), and QL (a DSL for questionnaires). The results show that usable block-based environments can be derived from context-free grammars, and with an order of magnitude reduction in effort.
Original languageEnglish
Title of host publicationSLE 2020 - Proceedings of the 13th ACM SIGPLAN International Conference on Software Language Engineering, Co-located with SPLASH 2020
EditorsRalf Lammel, Laurence Tratt, Juan de Lara
Number of pages13
ISBN (Electronic)9781450381765
Publication statusPublished - 1 Nov 2020


  • Blockly
  • DSLs
  • Rascal
  • block-based environments
  • grammars
  • language workbenches
  • syntax
  • visual languages


Dive into the research topics of 'Block-Based Syntax from Context-Free Grammars'. Together they form a unique fingerprint.

Cite this