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Improve docs spacing, remove spurious output in unittest

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This commit is contained in:
Andrei Alexandrescu 2016-10-21 08:48:57 -04:00
parent 30626d289d
commit d3ddf0fd38
1 changed files with 44 additions and 48 deletions
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92
std/experimental/checkedint.d
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@ -33,32 +33,31 @@ This module provides a few predefined hooks (below) that add useful behavior to
`Checked`:
$(UL
$(LI $(LREF Abort) fails every incorrect operation with a message to $(REF
stderr, std, stdio) followed by a call to `assert(0)`. It is the default
second parameter, i.e. `Checked!short` is the same as $(D Checked!(short,
Abort)).)
Abort)).
)
$(LI $(LREF Warn) prints incorrect operations to $(REF stderr, std, stdio) but
otherwise preserves the built-in behavior.)
otherwise preserves the built-in behavior.
)
$(LI $(LREF ProperCompare) fixes the comparison operators `==`, `!=`, `<`, `<=`, `>`,
and `>=` to return correct results in all circumstances, at a slight cost in
efficiency. For example, $(D Checked!(uint, ProperCompare)(1) > -1) is `true`,
which is not the case for the built-in comparison. Also, comparing numbers for
equality with floating-point numbers only passes if the integral can be
converted to the floating-point number precisely, so as to preserve transitivity
of equality.)
of equality.
)
$(LI $(LREF WithNaN) reserves a special "Not a Number" value akin to the homonym
value reserved for floating-point values. Once a $(D Checked!(X, WithNaN)) gets
this special value, it preserves and propagates it until reassigned.)
this special value, it preserves and propagates it until reassigned.
)
$(LI $(LREF Saturate) implements saturating arithmetic, i.e. $(D Checked!(int,
Saturate)) "stops" at `int.max` for all operations that would cause an `int` to
overflow toward infinity, and at `int.min` for all operations that would
correspondingly overflow toward negative infinity.)
correspondingly overflow toward negative infinity.
)
)
These policies may be used alone, e.g. $(D Checked!(uint, WithNaN)) defines a
@ -68,7 +67,6 @@ checked integral emulates an actual integral, which means another checked
integral can be built on top of it. Some combinations of interest include:
$(UL
$(LI $(D Checked!(Checked!int, ProperCompare)) defines an `int` with fixed
comparison operators that will fail with `assert(0)` upon overflow. (Recall that
`Abort` is the default policy.) The order in which policies are combined is
@ -76,14 +74,14 @@ important because the outermost policy (`ProperCompare` in this case) has the
first crack at intercepting an operator. The converse combination $(D
Checked!(Checked!(int, ProperCompare))) is meaningless because `Abort` will
intercept comparison and will fail without giving `ProperCompare` a chance to
intervene.)
intervene.
)
$(LI $(D Checked!(Checked!(int, ProperCompare), WithNaN)) defines an `int`-like
type that supports a NaN value. For values that are not NaN, comparison works
properly. Again the composition order is important; $(D Checked!(Checked!(int,
WithNaN), ProperCompare)) does not have good semantics because `ProperCompare`
intercepts comparisons before the numbers involved are tested for NaN.)
intercepts comparisons before the numbers involved are tested for NaN.
)
)
The hook's members are looked up statically in a Design by Introspection manner
@ -93,49 +91,48 @@ In the table, `hook` is an alias for `Hook` if the type `Hook` does not
introduce any state, or an object of type `Hook` otherwise.
$(TABLE ,
$(TR $(TH `Hook` member) $(TH Semantics in $(D Checked!(T, Hook))))
$(TR $(TH `Hook` member) $(TH Semantics in $(D Checked!(T, Hook)))
)
$(TR $(TD `defaultValue`) $(TD If defined, `Hook.defaultValue!T` is used as the
default initializer of the payload.))
default initializer of the payload.)
)
$(TR $(TD `min`) $(TD If defined, `Hook.min!T` is used as the minimum value of
the payload.))
the payload.)
)
$(TR $(TD `max`) $(TD If defined, `Hook.max!T` is used as the maximum value of
the payload.))
the payload.)
)
$(TR $(TD `hookOpCast`) $(TD If defined, `hook.hookOpCast!U(get)` is forwarded
to unconditionally when the payload is to be cast to type `U`.))
to unconditionally when the payload is to be cast to type `U`.)
)
$(TR $(TD `onBadCast`) $(TD If defined and `hookOpCast` is $(I not) defined,
`onBadCast!U(get)` is forwarded to when the payload is to be cast to type `U`
and the cast would lose information or force a change of sign.))
and the cast would lose information or force a change of sign.)
)
$(TR $(TD `hookOpEquals`) $(TD If defined, $(D hook.hookOpEquals(get, rhs)) is
forwarded to unconditionally when the payload is compared for equality against
value `rhs` of integral, floating point, or Boolean type.))
value `rhs` of integral, floating point, or Boolean type.)
)
$(TR $(TD `hookOpCmp`) $(TD If defined, $(D hook.hookOpCmp(get, rhs)) is
forwarded to unconditionally when the payload is compared for ordering against
value `rhs` of integral, floating point, or Boolean type.))
value `rhs` of integral, floating point, or Boolean type.)
)
$(TR $(TD `hookOpUnary`) $(TD If defined, `hook.hookOpUnary!op(get)` (where `op`
is the operator symbol) is forwarded to for unary operators `-` and `~`. In
addition, for unary operators `++` and `--`, `hook.hookOpUnary!op(payload)` is
called, where `payload` is a reference to the value wrapped by `Checked` so the
hook can change it.))
hook can change it.)
)
$(TR $(TD `hookOpBinary`) $(TD If defined, $(D hook.hookOpBinary!op(get, rhs))
(where `op` is the operator symbol and `rhs` is the right-hand side operand) is
forwarded to unconditionally for binary operators `+`, `-`, `*`, `/`, `%`,
`^^`, `&`, `|`, `^`, `<<`, `>>`, and `>>>`.))
`^^`, `&`, `|`, `^`, `<<`, `>>`, and `>>>`.)
)
$(TR $(TD `hookOpBinaryRight`) $(TD If defined, $(D
hook.hookOpBinaryRight!op(lhs, get)) (where `op` is the operator symbol and
`lhs` is the left-hand side operand) is forwarded to unconditionally for binary
operators `+`, `-`, `*`, `/`, `%`, `^^`, `&`, `|`, `^`, `<<`, `>>`, and `>>>`.))
operators `+`, `-`, `*`, `/`, `%`, `^^`, `&`, `|`, `^`, `<<`, `>>`, and `>>>`.)
)
$(TR $(TD `onOverflow`) $(TD If defined, `hook.onOverflow!op(get)` is forwarded
to for unary operators that overflow but only if `hookOpUnary` is not defined.
Unary `~` does not overflow; unary `-` overflows only when the most negative
@ -143,23 +140,23 @@ value of a signed type is negated, and the result of the hook call is returned.
When the increment or decrement operators overflow, the payload is assigned the
result of `hook.onOverflow!op(get)`. When a binary operator overflows, the
result of $(D hook.onOverflow!op(get, rhs)) is returned, but only if `Hook` does
not define `hookOpBinary`.))
not define `hookOpBinary`.)
)
$(TR $(TD `hookOpOpAssign`) $(TD If defined, $(D hook.hookOpOpAssign!op(payload,
rhs)) (where `op` is the operator symbol and `rhs` is the right-hand side
operand) is forwarded to unconditionally for binary operators `+=`, `-=`, `*=`, `/=`, `%=`,
`^^=`, `&=`, `|=`, `^=`, `<<=`, `>>=`, and `>>>=`.))
`^^=`, `&=`, `|=`, `^=`, `<<=`, `>>=`, and `>>>=`.)
)
$(TR $(TD `onLowerBound`) $(TD If defined, $(D hook.onLowerBound(value, bound))
(where `value` is the value being assigned) is forwarded to when the result of
binary operators `+=`, `-=`, `*=`, `/=`, `%=`, `^^=`, `&=`, `|=`, `^=`, `<<=`, `>>=`,
and `>>>=` is smaller than the smallest value representable by `T`.))
and `>>>=` is smaller than the smallest value representable by `T`.)
)
$(TR $(TD `onUpperBound`) $(TD If defined, $(D hook.onUpperBound(value, bound))
(where `value` is the value being assigned) is forwarded to when the result of
binary operators `+=`, `-=`, `*=`, `/=`, `%=`, `^^=`, `&=`, `|=`, `^=`, `<<=`, `>>=`,
and `>>>=` is larger than the largest value representable by `T`.))
and `>>>=` is larger than the largest value representable by `T`.)
)
)
*/
@ -2182,7 +2179,6 @@ static:
unittest
{
assert(checked!Saturate(int.max) + 1 == int.max);
import std.stdio; writeln(checked!Saturate(100) ^^ 10);
assert(checked!Saturate(100) ^^ 10 == int.max);
assert(checked!Saturate(-100) ^^ 10 == int.max);
assert(checked!Saturate(100) / 0 == int.max);