AST: parse a.b as (. a b)
#325
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I was working a bit on macro expansion - particularly `quote` (quasiquote) expansion with `$` interpolations - and I've found that it's weird and inconvenient that we parse `a.b` into `(. a (quote b))`. Specifically, the part that's weird here is that we emit `(quote b)` for the field name even though this is "not quote syntax": this should not yield a syntax literal during lowering, and is thus a semantic mismatch with actual quote syntax of the form `:(a + b)` or `quote a+b end`. * Why is this a problem? It means we need special rules to distinguish actual syntax literals from field names. * But can we really change this? Surely this AST form had a purpose? Yes! A long time ago Julia supported `a.(b)` syntax to mean `getfield(a, b)`, which would naturally have been parsed as `(. a b)`. However this was deprecated as part of adding broadcast syntax in JuliaLang/julia#15032 Here we simplify by parsing `a.b` as `(. a b)` instead, with the second argument implied to be a field name.
Codecov Report
@@ Coverage Diff @@
## main #325 +/- ##
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- Coverage 96.56% 96.54% -0.03%
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Files 14 14
Lines 4139 4140 +1
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Hits 3997 3997
- Misses 142 143 +1
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Fix #324 as described there.