Elm.Data.Located

Wrapper for location metadata. The location is essentially a pair of (row,col) coordinates for some span of source code.

Useful for error messages, but hopefully for stuff like source maps etc. too.

Types

type Located expr

Holds location metadata and some value.

type alias Region =

{ start : Position

, end : Position

}

type alias Position =

{ row : Int

, col : Int

}

located : Region -> expr -> Located expr

A constructor for the Located type.

Return the value inside the wrapper.

Return the location info inside the wrapper.

map : (a -> b) -> Located a -> Located b

Apply a function to the value inside the wrapper.

Merge the regions of the two wrappers.

Replace the value inside the wrapper with another.

Empty, meaningless region. Used in tests or where you don't need the location info but need to appease the typesystem.

mergeRegions : Region -> Region -> Region

Merge the regions: the resulting region is always bigger or equal than the input regions.

mergeRegions <1:1 - 4:4> <2:2 - 3:3>
    --> <1:1 - 4:4>

The order doesn't matter:

mergeRegions <2:2 - 3:3> <1:1 - 4:4>
    --> <1:1 - 4:4>

One doesn't have to be a subset of the other:

mergeRegions <1:1 - 3:3> <2:2 - 4:4>
    --> <1:1 - 4:4>

There can be gaps in between

mergeRegions <1:1 - 2:2> <4:4 - 5:5>
    --> <1:1 - 5:5>

regionToComparable : Region -> ( ( Int, Int ), ( Int, Int ) )

Transforms the record into something comparable.

positionToComparable : Position -> ( Int, Int )

Transforms the record into something comparable.

comparePosition : Position -> Position -> Order