Fix Statement vs Expr #51

jakzale · 2020-03-17T14:32:14Z

In most imperative programming languages statements are the top level forms, with expressions occurring inside statements. At the moment, the language is inside-out, by having statements inside expressions.

We can solve that in two possible ways:

make the statements toplevel, with expressions occuring inside them, or
forego statements altogether by introducing unit type and treating ; as expression sequencing operator (Add the unit type #44).

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effectfully · 2020-03-31T14:19:09Z

forego statements altogether by introducing unit type and treating ; as expression sequencing operator

Quoting another comment (that I just left):

we distinguish between expressions and statements right now (which is something that we have to do, because assertions can only be compiled when they're at the top level, see this comment, so "statements" arise naturally).

I did think about this option of having unit and ; as a sequencing operator, but compiling that is hard and inefficient and it's not clear if this level of generality gives us anything substantial.

We could allow uncompilable syntax trees, but I'd rather clearly express the intentions in the structure of the AST, when possible.

Fixes effectfully#51, effectfully#52 We make the following changes to the AST by adding - a newly introduced a top-level `Program` node, which is parent to - a newly introduced `Statements` node, which is parent to - a `Statement` node, which is chaned to be a parent of - an `Expr` node. In addition we introduce a `EFor` node to the typed AST. We update update the evaluator by providing an explicit transformer stack, `EvalT`, and we fix the semantics for for loops. We also add the following minor improvements - we fix `Sign` vs `Sig` naming issue, - clean up some naming conventions, - provide `stack bench` benchmark for testing generators for the new AST.

Fixes effectfully#51, effectfully#52 We make the following changes to the AST by adding - a newly introduced a top-level `Program` node, which is parent to - a newly introduced `Statements` node, which is parent to - a `Statement` node, which is chaned to be a parent of - an `Expr` node. We make the following changes to Statement by - introduce a `EFor` node to the typed AST. We update update the evaluator by - providing an explicit transformer stack (`EvalT`), - fixing the semantics for for loops, and - switching to CPS both in evaluator and normaliser. We also add minor improvements to the codebase by - fixing `Sign` vs `Sig` naming issue, - cleaning up some naming conventions, and - providing `stack bench` benchmark for testing generators for the new AST.

* [AST] fix statement vs expression Fixes #51, #52 We make the following changes to the AST by adding - a newly introduced a top-level `Program` node, which is parent to - a newly introduced `Statements` node, which is parent to - a `Statement` node, which is chaned to be a parent of - an `Expr` node. We make the following changes to Statement by - introduce a `EFor` node to the typed AST. We update update the evaluator by - providing an explicit transformer stack (`EvalT`), - fixing the semantics for for loops, and - switching to CPS both in evaluator and normaliser. We also add minor improvements to the codebase by - fixing `Sign` vs `Sig` naming issue, - cleaning up some naming conventions, and - providing `stack bench` benchmark for testing generators for the new AST.

effectfully added AST Important labels Mar 17, 2020

effectfully mentioned this issue Mar 20, 2020

Add the unit type #44

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jakzale mentioned this issue Mar 31, 2020

Add proper declarations #33

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jakzale mentioned this issue Apr 3, 2020

Fix statement vs expr #62

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effectfully closed this as completed in #62 May 18, 2020

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Fix Statement vs Expr #51

Fix Statement vs Expr #51

jakzale commented Mar 17, 2020 •

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effectfully commented Mar 31, 2020

Fix Statement vs Expr #51

Fix Statement vs Expr #51

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jakzale commented Mar 17, 2020 • edited Loading

effectfully commented Mar 31, 2020

jakzale commented Mar 17, 2020 •

edited

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