def build_Tuple(ctx, expr):
return TupleLiteral(
ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + 1),
[build_expr(ctx, e) for e in expr.elts])
def build_Subscript(ctx, expr):
def build_SliceExpr(ctx, base, slice_expr):
lower = build_expr(
ctx,
slice_expr.lower) if slice_expr.lower is not None else None
upper = build_expr(
ctx,
slice_expr.upper) if slice_expr.upper is not None else None
step = build_expr(
ctx, slice_expr.step) if slice_expr.step is not None else None
return SliceExpr(base.range(), lower, upper, step)
def build_Index(ctx, base, index_expr):
if isinstance(index_expr.value, ast.Tuple):
raise NotSupportedError(
base.range(), "slicing multiple dimensions with "
"tuples not supported yet")
return build_expr(ctx, index_expr.value)
def build_ExtSlice(ctx, base, extslice):
sub_exprs = []
for expr in extslice.dims:
sub_type = type(expr)
if sub_type is ast.Index:
sub_exprs.append(build_Index(ctx, base, expr))
elif sub_type is ast.Slice:
sub_exprs.append(build_SliceExpr(ctx, base, expr))
elif sub_type is ast.Ellipsis:
sub_exprs.append(Dots(base.range()))
else:
raise NotSupportedError(
base.range(), "slicing multiple dimensions with "
"{} not supported".format(sub_type))
return sub_exprs
base = build_expr(ctx, expr.value)
sub_type = type(expr.slice)
if sub_type is ast.Index:
if isinstance(expr.slice.value, ast.Tuple):
# N-dimensional indexing using Tuple: x[(i, j, k)] is equivalent to x[i, j, k]
# XXX: Indexing using a list is **different**! It triggers advanced indexing.
indices = [
build_expr(ctx, index_expr)
for index_expr in expr.slice.value.elts
]
if not indices:
# `col_offset` is an int, but `end_col_offset` is
# `Optional[int]`. The magic number is here to make
# sure we can parse `()` on any machine
r = ctx.make_range(expr.lineno,
expr.slice.value.col_offset,
expr.slice.value.col_offset + 2)
tup = TupleLiteral(r, [])
indices.append(tup)
return Subscript(base, indices)
else:
return Subscript(base, [build_expr(ctx, expr.slice.value)])
elif sub_type is ast.Slice:
return Subscript(base, [build_SliceExpr(ctx, base, expr.slice)])
elif sub_type is ast.ExtSlice:
return Subscript(base, build_ExtSlice(ctx, base, expr.slice))
elif sys.version_info >= (
3,
9): # In Python3.9 array indicies are not wrapped in ast.Index
if sub_type is ast.Tuple:
# N-dimensional indexing using Tuple: x[(i, j, k)] is equivalent to x[i, j, k]
indices = []
for index_expr in expr.slice.elts:
if isinstance(index_expr, ast.Slice):
indices.append(build_SliceExpr(ctx, base, index_expr))
else:
indices.append(build_expr(ctx, index_expr))
# Special-case logic for `typing.Tuple[()]`
if not indices:
# See note above r.e. magic number
r = ctx.make_range(expr.lineno, expr.slice.col_offset,
expr.slice.col_offset + 2)
tup = TupleLiteral(r, [])
indices.append(tup)
return Subscript(base, indices)
return Subscript(base, [build_expr(ctx, expr.slice)])
else: # Ellipsis (can only happen in Python 2)
raise NotSupportedError(base.range(), "ellipsis is not supported")