parsing - How does Swift disambiguate generic constructors? -

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consider following swift expression

println(generic<foo, bar>(1))

normally, 1 read generic call constructor generic<foo, bar> arguments (1).

println( generic<foo,bar>(1) )

however, when re-arranging tokens bit, represent 2 separate comparisons, example if generic , foo poorly named numeric variables:

println(generic < foo, bar > (1)) // or, proper parenthesis println((generic < foo), (bar > 1))

what can observe here expression generic constructor highly ambiguous, , not easy disambiguate humans. problem here swift doesn't have new keyword constructors, makes them ambiguous method calls , operators in cases. thus, interested in how swift compiler (parser) manages disambiguate above expressions. way parsed dependant on context (types, variables, functions) or can resolved parser?

the answer simple: compiler does't allow declare these variables:

struct generic<t, u> {      init(_ i: int) {} } struct foo {} struct bar {}  print(generic<foo, bar>(1))  // error let foo = 0      // invalid redeclaration of foo let bar = 3      // invalid redeclaration of bar let generic = 5  // invalid redeclaration of generic print(generic<foo, bar>(1))

making either variables or type declarations in source file current declaration "overrides" other one.


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