Safe Haskell | None |
---|---|

Language | Haskell2010 |

This modle contains a number of classes for building constraints of one variable.

Whilst this package can stand alone, it was developed to be used in conjuction with the package "polydata". Hence the documentation here is brief and examples (and indeed test cases currently) are more from the package "polydata".

- class (c1 a, c2 a) => (c1 &&& c2) a
- class (c1 a, c2 a) => And c1 c2 a
- data Arg n
- data Result n
- type family GetArg t a where ...
- class GetArg i a ~ t => IxIs i t a
- class GetArg i1 a ~ GetArg i2 a => IxEqual i1 i2 a
- class c (GetArg i a) => IxConstrainBy i c a
- class c (GetArg i1 a) (GetArg i2 a) => IxConstrainPair c i1 i2 a
- class GetArg i1 a ~ f (GetArg i2 a) => IxConstructorEqual i1 f i2 a
- class (GetArg i1 a ~ f (GetArg i2 a), c f) => IxConstraintedConstructorEqual i1 c f i2 a

# Documentation

class (c1 a, c2 a) => (c1 &&& c2) a Source #

This class combines two constraints. Given:

c1 :: * -> Constraint c2 :: * -> Constraint

then

(c1 &&& c2) :: * -> Constraint

is only satisfied when both `c1`

and `c2`

are satisfied. This is useful for building constraints.

The following types `Arg`

and `Result`

, and `GetArg`

are used to reference particular arguments of functions.

It's worth remembering `Arg`

is zero based, so the first argument is `Arg 0`

.

With `Result`

, you still need to specify the number of arguments. So

GetArg (Result 2) (t1 -> t2 -> t3) == t3

Naturally:

GetArg (Result 1) (t1 -> t2 -> t3) == t2 -> t3

as

(t1 -> t2 -> t3) == (t1 -> (t2 -> t3))

class GetArg i a ~ t => IxIs i t a Source #

IxIs i t

is a constraint that says element `i`

is `t`

.

For example:

IxIs (Arg 1) Int

is of type `* -> Constraint`

such that

IxIs (Arg 1) Int t

says that second argument of `t`

is Int. Remember that for this library, function args are 0 based.

IxIs (Result 2) Int t

says the result of the two argument function is Int. The definition is:

IxIs i t a == GetArg i a ~ t

class GetArg i1 a ~ GetArg i2 a => IxEqual i1 i2 a Source #

`IxEqual i1 i2 a`

just says arguments `i1`

and `i2`

are equal. i.e.

IxEqual i1 i2 a == GetArg i1 a ~ GetArg i2 a

class c (GetArg i a) => IxConstrainBy i c a Source #

`IxConstrainBy i c a`

applies constraint `c`

to the ith argument. i.e.

IxConstrainBy i c a == c (GetArg i a)

c (GetArg i a) => IxConstrainBy i c a Source # | |

class c (GetArg i1 a) (GetArg i2 a) => IxConstrainPair c i1 i2 a Source #

`IxConstrainPair c i1 i2`

applies two argument constraint `c`

to the `i1`

th and `i2`

th element in that order. i.e.

IxConstrainPair c i1 i2 a == c (GetArg i1 a) (GetArg i2 a)

c (GetArg i1 a) (GetArg i2 a) => IxConstrainPair c i1 i2 a Source # | |

class GetArg i1 a ~ f (GetArg i2 a) => IxConstructorEqual i1 f i2 a Source #