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PrefixType renamed to PrefixFamily + units hierarchy PNG fixed

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This commit is contained in:
Mateusz Pusz
2020-03-19 14:44:56 +01:00
parent a9432b1407
commit 034f239f96
10 changed files with 146 additions and 68 deletions
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docs/DESIGN.md
+11 -11
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@@ -97,12 +97,12 @@ All below class templates indirectly derive from a `scaled_unit` class template
- Defines a named, in most cases base or coherent unit that is then passed to a dimension's
definition.
- A named unit may be used by other units defined with the prefix of the same type, unless
`no_prefix` is provided for `PrefixType` template parameter (in such a case it is impossible
`no_prefix` is provided for `PrefixFamily` template parameter (in such a case it is impossible
to define a prefixed unit based on this one).
- `named_scaled_unit`
- Defines a new named unit that is a scaled version of another unit.
- Such unit can be used by other units defined with the prefix of the same type, unless
`no_prefix` is provided for `PrefixType` template parameter (in such a case it is impossible
`no_prefix` is provided for `PrefixFamily` template parameter (in such a case it is impossible
to define a prefixed unit based on this one).
- `prefixed_unit`
- Defines a new unit that is a scaled version of another unit by the provided prefix.
@@ -115,26 +115,26 @@ All below class templates indirectly derive from a `scaled_unit` class template
- All of the units provided should also be a named ones so it is possible to create a deduced
symbol text.
Some of the above types depend on `PrefixType` and `no_prefix`. `PrefixType` is a concept that
Some of the above types depend on `PrefixFamily` and `no_prefix`. `PrefixFamily` is a concept that
is defined as:
```cpp
template<typename T>
concept PrefixType = std::derived_from<T, prefix_type>;
concept PrefixFamily = std::derived_from<T, prefix_family>;
```
where `prefix_type` is just an empty tag type used to identify the beginning of prefix types
where `prefix_family` is just an empty tag type used to identify the beginning of prefix types
hierarchy and `no_prefix` is one of its children:
```cpp
struct prefix_type {};
struct no_prefix : prefix_type {};
struct prefix_family {};
struct no_prefix : prefix_family {};
```
Concrete prefix derives from a `prefix` class template:
```cpp
template<typename Child, PrefixType PT, basic_fixed_string Symbol, Ratio R>
template<typename Child, PrefixFamily PT, basic_fixed_string Symbol, Ratio R>
requires (!std::same_as<PT, no_prefix>)
struct prefix;
```
@@ -151,7 +151,7 @@ Coming back to units, here are a few examples of unit definitions:
namespace units::si {
// prefixes
struct prefix : prefix_type {};
struct prefix : prefix_family {};
struct centi : units::prefix<centi, prefix, "c", ratio<1, 1, -2>> {};
struct kilo : units::prefix<kilo, prefix, "k", ratio<1, 1, 3>> {};
@@ -508,7 +508,7 @@ a series of checks:
dimension:
- prefix:
- if ratio of the scaled unit is `1`, than no prefix is being printed,
- otherwise, if `PrefixType` template parameter of a reference unit is different than
- otherwise, if `PrefixFamily` template parameter of a reference unit is different than
`no_prefix`, and if the ratio of scaled unit matches the ratio of a prefix of a specified
type, than the symbol of this prefix will be used,
- otherwise, non-standard ratio (i.e. `2 [60]Hz`) will be printed.
@@ -781,7 +781,7 @@ adds support for digital information quantities. In summary it adds:
```cpp
namespace units::data {
struct prefix : prefix_type {};
struct prefix : prefix_family {};
struct kibi : units::prefix<kibi, prefix, "Ki", ratio< 1'024>> {};
struct mebi : units::prefix<mebi, prefix, "Mi", ratio<1'048'576>> {};