This poster showing the grammar of Pascal in colourful railroad diagrams is rather glorious! Found in “50 Years of Pascal”: cacm.acm.org/magazines/2021
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How about Oberon? :O
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Also, can somebody come up with 'railroad diagrams' for inference rules?
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how do they look?
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The idea is that you each inference rule is kind of a 'branch node' and the axioms are 'leaf nodes' and you slot them together to build a proof tree.
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oh yes! these look very diagrammable!
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Yeah I reckon so! I think the big issue I have with them though is scaling them to full language specs - the current inference rule notation works for small stuff, but can get unmanageable quickly.
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I was thinking it would be neat to have some text notation to define the rules, and then a way of presenting them that implementors can use - perhaps with a way of switching between a diagram version, generated 'prose', and more traditional maths notation.
With clickable links to jump to definitions and usages, ways of grouping based on judgement vs syntactic construct, and an index of rules, judgements and syntax.
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