f0999de9dc
During the instantiation of a generic type A, some other generic type B may be instantiated multiple times with different parameters. We can think about each instantiation as a function call that should temporary bind the parameter names to concrete types. The problem with the existing implementation in semtypinst was that it was performing this binding within a shared global table. In this sense, it was executing the code as a programming language featuring only global variables. In such a language, re-entrant functions cannot be defined properly and hence this was leading to problems with similar types. The solution is simple - just like we need to introduce stack frames to handle re-entrant functions, we introduce a stack of type bindings that are pushed and popped during the generic instantiations.
81 lines
2.3 KiB
Nim
81 lines
2.3 KiB
Nim
discard """
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output: '''
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(Field0: 10, Field1: (Field0: test, Field1: 1.2))
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3x3 Matrix [[0.0, 2.0, 3.0], [2.0, 0.0, 5.0], [2.0, 0.0, 5.0]]
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2x3 Matrix [[0.0, 2.0, 3.0], [2.0, 0.0, 5.0]]
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2x3 Literal [[0.0, 2.0, 3.0], [2.0, 0.0, 5.0]]
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2x3 Matrix [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]
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2x2 ArrayArray[[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]
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2x3 ArrayVector[[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]
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2x3 VectorVector [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]
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2x3 VectorArray [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]
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'''
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"""
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# https://github.com/nim-lang/Nim/issues/5962
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type
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ArrayLike[A, B] = (A, B)
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VectorLike*[SIZE, T] = ArrayLike[SIZE, T]
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MatrixLike*[M, N, T] = VectorLike[M, VectorLike[N, T]]
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proc tupleTest =
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let m: MatrixLike[int, string, float] = (10, ("test", 1.2))
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echo m
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tupleTest()
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type
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Vector*[K: static[int], T] =
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array[K, T]
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Matrix*[M: static[int]; N: static[int]; T] =
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Vector[M, Vector[N, T]]
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proc arrayTest =
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# every kind of square matrix works just fine
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let mat_good: Matrix[3, 3, float] = [[0.0, 2.0, 3.0],
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[2.0, 0.0, 5.0],
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[2.0, 0.0, 5.0]]
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echo "3x3 Matrix ", repr(mat_good)
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# this does not work with explicit type signature (the matrix seems to always think it is NxN instead)
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let mat_fail: Matrix[2, 3, float] = [[0.0, 2.0, 3.0],
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[2.0, 0.0, 5.0]]
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echo "2x3 Matrix ", repr(mat_fail)
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# this literal seems to work just fine
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let mat_also_good = [[0.0, 2.0, 3.0],
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[2.0, 0.0, 5.0]]
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echo "2x3 Literal ", repr(mat_also_good)
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# but making a named type out of this leads to pretty nasty runtime behavior
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var mat_fail_runtime: Matrix[2, 3, float]
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echo "2x3 Matrix ", repr(mat_fail_runtime)
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# cutting out the matrix type middle man seems to solve our problem
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var mat_ok_runtime: array[2, array[3, float]]
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echo "2x2 ArrayArray", repr(mat_ok_runtime)
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# this is fine too
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var mat_ok_runtime_2: array[2, Vector[3, float]]
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echo "2x3 ArrayVector", repr(mat_ok_runtime_2)
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# here we are in trouble again
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var mat_fail_runtime_2: Vector[2, Vector[3, float]]
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echo "2x3 VectorVector ", repr(mat_fail_runtime_2)
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# and here we are fine again
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var mat_ok_runtime_3: Vector[2, array[3, float]]
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echo "2x3 VectorArray ", repr(mat_ok_runtime_3)
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arrayTest()
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