Comments on: Syntax Diagrams for APEXlang

By: Friedhold Matz

Friedhold Matz — Fri, 19 Jun 2026 19:33:50 +0000

Here is Prof. Niklaus Wirth’s Modula-2 language definition incl. the EBNF of Modula-2:
https://www.research-collection.ethz.ch/bitstreams/289cc859-94e5-4758-8786-ac05437780a2/download
and about the syntax notation: https://grokipedia.com/page/Wirth_syntax_notation
A good paper about EBNF: https://www.cs.cmu.edu/~pattis/misc/ebnf2.pdf .

By: Philipp Salvisberg

Philipp Salvisberg — Fri, 19 Jun 2026 16:53:01 +0000

In reply to Friedhold Matz.

Perhaps a good approach would be to provide EBNF converters as Python libraries for various use cases.

To do this, we need a complete list of EBNFs with full specifications.
I tried to find the Wirth EBNF specification, but was unsuccessful.
In my opinion, a parser is required for each EBNF to produce reliable transpiler results.
The approach I took in this case is somewhat hacky, but it works for the current version of apexlang.ebnf.

Please let me know once you have found (provided?) such a library. ;-)

By: Friedhold Matz

Friedhold Matz — Fri, 19 Jun 2026 16:17:01 +0000

I still remember when Prof. Niklaus Wirth defined Modula-2 using EBNF; that marked a significant breakthrough and an attempt to standardise language specifications. Nowadays, there are many representation formats for EBNF—for verifiers, compiler generators, parser tools, railroad diagrams, and so on—as well as an ISO standard for EBNF: https://www.cl.cam.ac.uk/~mgk25/iso-14977.pdf.
Perhaps a good approach would be to provide EBNF converters as Python libraries for various use cases.
In any case, Oracle has taken a promising path with EBNF for APEXlang—much like they did for PGQL (https://pgql-lang.org/).