prequel/span

Types

Position

The position of a line (or column) relative to a span: it could either be its first or last line, it could be inside the span, or it could be outside of it.

You can look at the classify_line for an example usage of this type.

pub type Position {
  First
  Inside
  Last
  Outside
}

Constructors

```
First
```
```
Inside
```
```
Last
```
```
Outside
```

Span

</>

A span indicating a slice of a source code file.

pub type Span {
  Span(
    start_line: Int,
    end_line: Int,
    start_column: Int,
    end_column: Int,
  )
}

Constructors

Span(
  start_line: Int,
  end_line: Int,
  start_column: Int,
  end_column: Int,
)

Functions

classify_line

</>

pub fn classify_line(span: Span, line: Int) -> Position

Returns the position of a line relative to the given span:

First means that the given line is the first line of the span
Last means that the given line is the last line of the span
Inside means that the line falls between the first and last lines of the span
Outside is for a line that is not contained inside the span

Examples

> classify_line(new(1, 3, 2, 2), 1)
First

> classify_line(new(1, 3, 2, 2), 2)
Inside

> classify_line(new(1, 3, 2, 2), 3)
Last

> classify_line(new(1, 3, 2, 2), 4)
Outside

columns

</>

pub fn columns(span: Span) -> NonEmptyList(Int)

Returns a non empty list with the starting and ending columns of a span.

Examples

> lines(point(11, 1)) |> non_empty_list.to_list
[1]

> lines(new(11, 15, 2, 4)) |> non_empty_list.to_list
[2, 4]

contains_line

</>

pub fn contains_line(span: Span, line: Int) -> Bool

Returns true if the given line is contained inside the span.

## Examples

> new(1, 11, 2, 3) |> contains_line(1)
True

> new(1, 11, 2, 3) |> contains_line(11)
True

> new(1, 11, 2, 3) |> contains_line(10)
True

> new(1, 11, 2, 3) |> contains_line(12)
False

ends_on_line

</>

pub fn ends_on_line(span: Span, line: Int) -> Bool

Returns true if the span ends on the given line.

## Examples

> point(1, 2) |> ends_on_line(1)
True

> point(11, 2) |> ends_on_line(1)
False

is_segment

</>

pub fn is_segment(span: Span) -> Bool

Returns true if the given span is a single-line segment, that is if its starting and ending line are the same.

Examples

> is_segment(segment(1, 2, 3))
True

> is_segment(point(2, 5))
True

> is_segment(new(1, 2, 3, 4))
False

lines

</>

pub fn lines(span: Span) -> NonEmptyList(Int)

Returns a non empty list with the starting and ending lines of a span.

Examples

> lines(point(11, 1)) |> non_empty_list.to_list
[11]

> lines(new(11, 15, 2, 4)) |> non_empty_list.to_list
[11, 15]

max_column

</>

pub fn max_column(spans: NonEmptyList(Span)) -> Int

Returns the smallest line in a non empty list of spans.

## Examples

> non_empty_list.new(point(14, 1), [segment(2, 4, 5)])
> |> max_column
5

max_line

</>

pub fn max_line(spans: NonEmptyList(Span)) -> Int

Returns the greatest line in a non empty list of spans.

Examples

> non_empty_list.new(point(14, 1), [segment(2, 4, 5)])
> |> max_line
14

merge

</>

pub fn merge(one: Span, with other: Span) -> Span

Merge two spans together obtaining the largest possible span: it starts from the smallest line and column and ends at the largest line and column.

Examples

> point(1, 2) |> merge(point(3, 1))
Span(1, 3, 1, 2)

> new(1, 4, 3, 4) |> merge(new(3, 5, 2, 3))
Span(1, 5, 2, 4)

min_column

</>

pub fn min_column(spans: NonEmptyList(Span)) -> Int

Returns the smallest column in a non empty list of spans.

Examples

> non_empty_list.new(point(14, 1), [segment(2, 4, 5)])
> |> min_column
1

min_line

</>

pub fn min_line(spans: NonEmptyList(Span)) -> Int

Returns the smallest line in a non empty list of spans.

Examples

> non_empty_list.new(point(14, 1), [segment(2, 4, 5)])
> |> min_line
2

new

</>

pub fn new(start_line: Int, end_line: Int, start_column: Int, end_column: Int) -> Span

Creates a new span given its start line, end line, start column and end column.

Examples

> new(1, 2, 3, 4)
Span(1, 2, 3, 4)

point

</>

pub fn point(line: Int, column: Int) -> Span

Creates a span that spans over a single line and a single column.

## Examples

> point(1, 2)
Span(1, 1, 2, 2)

segment

</>

pub fn segment(line: Int, start_column: Int, end_column: Int) -> Span

Creates a span taht spans over a single line and multiple columns.

Examples

> segment(1, 2 ,5)
Span(1, 1, 2, 5)

starts_at_line

</>

pub fn starts_at_line(span: Span, line: Int) -> Bool

Returns true if the span starts at the given line.

## Examples

> point(1, 2) |> starts_at_line(1)
True

> point(11, 1) |> starts_at_line(1)
False