Creates composition of two paths which has some inspiration from logical and. This means that a &&& b path-closure tries to apply a and only if it returns {:ok, something}, tries apply b and if b returns exactly the same as a does, the a &&& b returns {:ok, something}

Example

iex> p1 = path :x / :y
iex> p2 = path :a / :b
iex> ap = p1 &&& p2
iex> {:ok, 1} = view %{x: %{y: 1}, a: [b: 1]}, ap
iex> :error = view %{x: %{y: 1}, a: [b: 2]}, ap
iex> {:ok, %{x: %{y: 2}, a: [b: 2]}} = set %{x: %{y: 1}, a: [b: 1]}, ap, 2
iex> {:ok, %{x: %{y: 2}, a: %{b: 2}}} = force_set %{}, ap, 2

Easy and convenient way to add pathex to your module.

You can specify modifier

use Pathex, default_mod: :json

Or just use it with default :naive modifier

use Pathex

use Pathex

When you use Pathex, the Pathex module will require Pathex and import Pathex's operators, path/2 and alongside/1 macros. Plus it will set special module attribute with default_mod value in it.

This macro creates compositions of paths which work along with each other

Think of alongside([path1, path2, path3]) as path1 &&& path2 &&& path3 The only difference is that for viewing alongside returns list of variables

Example

iex> pa = alongside [path(:x), path(:y)]
iex> {:ok, [1, 2]} = view(%{x: 1, y: 2}, pa)
iex> {:ok, %{x: 3, y: 3}} = set(%{x: 1, y: 2}, pa, 3)
iex> :error = set(%{x: 1}, pa, 3)
iex> {:ok, %{x: 1, y: 1}} = force_set(%{}, pa, 1)

Applies func under path in struct and returns result of this func.

Example

iex> x = 1
iex> {:ok, 9} = at [0, %{x: 8}], path(x / :x), fn x -> x + 1 end
iex> p = path "hey" / 0
iex> {:ok, {:here, 9}} = at(%{"hey" => {9, -9}}, p, & {:here, &1})

Applies func under path in struct and returns result of this func. Raises if path is not found.

Example

iex> x = 1
iex> 9 = at! [0, %{x: 8}], path(x / :x), fn x -> x + 1 end
iex> p = path "hey" / 0
iex> {:here, 9} = at!(%{"hey" => {9, -9}}, p, & {:here, &1})

The same as Pathex.~>/2 for those who do not like operators

Example

iex> p1 = path :x / :y
iex> p2 = path :a / :b
iex> composed_path = concat(p1, p2)
iex> {:ok, 1} = view %{x: [y: [a: [a: 0, b: 1]]]}, composed_path

Deletes value under path in struct.

Example

iex> x = 1
iex> {:ok, [0, %{}]} = delete([0, %{x: 8}], path(x / :x))
iex> :error = delete([0, %{x: 8}], path(1 / :y))

Deletes value under path in struct or raises if value is not found.

Example

iex> x = 1
iex> [0, %{}] = delete!([0, %{x: 8}], path(x / :x))

Gets the value under path in struct or returns default value if not found.

Example

iex> x = 1
iex> true = exists?([0, %{x: 8}], path(x / :x))
iex> p = path "hey" / "you"
iex> false = exists?(%{"hey" => [x: 1]}, p)

Applies func under path of struct.

If the path does not exist it creates the path favouring maps when structure is unknown and inserts default value.

Example

iex> x = 1
iex> {:ok, [0, %{x: {:xxx, 8}}]} = force_over([0, %{x: 8}], path(x / :x), & {:xxx, &1}, 123)
iex> p = path "hey" / 0
iex> {:ok, %{"hey" => %{0 => 1}}} = force_over(%{}, p, fn x -> x + 1 end, 1)

If the item in path doesn't have the right type, it returns :error.

Example

iex> p = path "hey" / "you"
iex> :error = force_over %{"hey" => {1, 2}}, p, fn x -> x end, "value"

Applies func under path of struct.

If the path does not exist it creates the path favouring maps when structure is unknown and inserts default value.

Example

iex> x = 1
iex> [0, %{x: {:xxx, 8}}] = force_over!([0, %{x: 8}], path(x / :x), & {:xxx, &1}, 123)
iex> p = path "hey" / 0
iex> %{"hey" => %{0 => 1}} = force_over!(%{}, p, fn x -> x + 1 end, 1)

If the item in path doesn't have the right type, it raises.

Example

iex> p = path "hey" / "you"
iex> force_over! %{"hey" => {1, 2}}, p, fn x -> x end, "value"
** (Pathex.Error) Type mismatch in structure

Sets the value under path in struct.

Creates path if it is not present

If the path does not exist it creates the path favouring maps when structure is unknown.

iex> x = 1
iex> {:ok, [0, %{x: 123}]} = force_set [0, %{x: 8}], path(x / :x), 123
iex> p = path "hey" / 0
iex> {:ok, %{"hey" => %{0 => 1}}} = force_set %{}, p, 1

Incorrect types may be detected during call

If the item in path doesn't have the right type, it returns :error.

iex> p = path "hey" / "you"
iex> :error = force_set %{"hey" => {1, 2}}, p, "value"

Empty space is filled with nil

Note that for paths created with Pathex.path/2 list and tuple indexes which are out of bounds fill the empty space with nil.

iex> p = path 4
iex> {:ok, [1, 2, 3, nil, 5]} = force_set [1, 2, 3], p, 5
iex> {:ok, {1, 2, 3, nil, 5}} = force_set {1, 2, 3}, p, 5

Negative indexes

This is also true for negative indexes (except -1 for lists which always prepends)

iex> p = path -5
iex> {:ok, [0, nil, 1, 2, 3]} = force_set [1, 2, 3], p, 0
iex> {:ok, {0, nil, 1, 2, 3}} = force_set {1, 2, 3}, p, 0

Sets the value under path in struct.

Creates path if it is not present

If the path does not exist it creates the path favouring maps when structure is unknown.

iex> x = 1
iex> [0, %{x: 123}] = force_set! [0, %{x: 8}], path(x / :x), 123
iex> p = path "hey" / 0
iex> %{"hey" => %{0 => 1}} = force_set! %{}, p, 1

Incorrect types may be detected during call

If the item in path doesn't have the right type, it raises.

iex> p = path "hey" / "you"
iex> force_set! %{"hey" => {1, 2}}, p, "value"
** (Pathex.Error) Type mismatch in structure

Empty space is filled with nil

Note that for paths created with Pathex.path/2 list and tuple indexes which are out of bounds fill the empty space with nil.

iex> p = path 4
iex> [1, 2, 3, nil, 5] = force_set! [1, 2, 3], p, 5
iex> {1, 2, 3, nil, 5} = force_set! {1, 2, 3}, p, 5

Negative indexes

This is also true for negative indexes (except -1 for lists which always prepends)

iex> p = path -5
iex> [0, nil, 1, 2, 3] = force_set! [1, 2, 3], p, 0
iex> {0, nil, 1, 2, 3} = force_set! {1, 2, 3}, p, 0

Gets the value under path in struct or returns default when path is not present. Note that the default value is always lazily evaluted.

Example

iex> x = 1
iex> 8 = get([0, %{x: 8}], path(x / :x))
iex> p = path "hey" / "you"
iex> nil = get(%{"hey" => [x: 1]}, p)
iex> :default = get(%{"hey" => [x: 1]}, p, :default)

@spec inspect(t()) :: iodata()

Inspect the given path-closure and returns string which corresponds to given path-closure

Example

iex> index = 1
iex> p = path(:x) ~> path(:y / index) &&& path(-1)
iex> Pathex.inspect(p)
"path(:x) ~> path(:y / 1) &&& path(-1)"

Applies func to the item under the path in struct and returns modified structure. Works like Map.update!/3 but doesn't raise.

Example

iex> index = 1
iex> inc = fn x -> x + 1 end
iex> {:ok, [0, %{x: 9}]} = over [0, %{x: 8}], path(index / :x), inc
iex> p = path "hey" / 0
iex> {:ok, %{"hey" => [2, [2]]}} = over %{"hey" => [1, [2]]}, p, inc

Note: Exceptions from passed function left unhandled

iex> over(%{1 => "x"}, path(1), fn x -> x + 1 end)
** (ArithmeticError) bad argument in arithmetic expression

Applies the func to the item under path in struct and returns modified structure. Works like Map.update!/3.

Example

iex> x = 1
iex> inc = fn x -> x + 1 end
iex> [0, %{x: 9}] = over! [0, %{x: 8}], path(x / :x), inc
iex> p = path "hey" / 0
iex> %{"hey" => [2, [2]]} = over! %{"hey" => [1, [2]]}, p, inc

Creates path from quoted ast. Paths look like unix filesystems paths and consist of elements separated from each other with /. Each element defines the key or index in the collection.

Example

iex> x = 1
iex> mypath = path 1 / :atom / "string" / {"tuple?"} / x
iex> structure = [0, [atom: %{"string" => %{{"tuple?"} => %{1 => 2}}}]]
iex> {:ok, 2} = view structure, mypath

Paths can be used with one of the verbs in Pathex module (for example, Pathex.view/2). Paths can be customized with modifiers, composed using one of composition operators (Pathex.concat/2, Pathex.~>/2, Pathex.|||/2, Pathex.&&&/2 or Pathex.alongside/1).

Note: Each element in path can have collection type annotated using :: operator. Available collection types are :list, :keyword, :tuple and :map. Multiple collections can be annotated using list It must comply with the limits set with modifier.

Example

iex> p = path( (0 :: [:list, :map]) / (:x :: :keyword) )
iex> {:ok, :hit} = view %{0 => [x: :hit]}, p
iex> {:ok, :hit} = view [[x: :hit]], p
iex> :error = view [%{x: :hit}], p

This macro converts path (which can be matched upon) into pattern.

These requirements must be satisfied in order for this macro to work correctly:

1. Path must be inlined into this macro. This means that path must be defined in a argument of this macro
2. Defined paths must contain constants only
3. Path must result only in case with one clause

Example

iex> import Pathex
iex> structure = %{users: %{1 => %{fname: "Jose", lname: "Valim"}}}
iex> case structure do
...>   pattern(fname, path(:users / 1 / :fname, :map)) ->
...>     {:ok, fname}
...>
...>   _ ->
...>     :error
...> end
{:ok, "Jose"}

Macro which gets value in the structure and deletes it.

Note:

Current implementation of this function performs double lookup. Which is still more efficient than pop_in

Example

iex> {:ok, {1, [2, 3]}} = pop([1, 2, 3], path(0))

Gets value under path in struct and then deletes it.

Note:

Current implementation of this function performs double lookup. Which is still more efficient than pop_in

Example

iex> {1, [2, 3]} = pop!([1, 2, 3], path(0))

Sets value under path in structure. Think of it like Map.put/3.

Example

iex> x = 1
iex> {:ok, [0, %{x: 123}]} = set [0, %{x: 8}], path(x / :x), 123
iex> p = path "hey" / 0
iex> {:ok, %{"hey" => [123, [2]]}} = set %{"hey" => [1, [2]]}, p, 123

Sets the value under path in struct. Think of it like Map.put/3.

Example

iex> x = 1
iex> [0, %{x: 123}] = set! [0, %{x: 8}], path(x / :x), 123
iex> p = path "hey" / 0
iex> %{"hey" => [123, [2]]} = set! %{"hey" => [1, [2]]}, p, 123

Gets the value under path in struct.

Example

iex> x = 1
iex> {:ok, 8} = view [0, %{x: 8}], path(x / :x)
iex> p = path "hey" / 0
iex> {:ok, 9} = view %{"hey" => {9, -9}}, p

Gets the value under path in struct. Raises if path not found.

Example

iex> x = 1
iex> 8 = view! [0, %{x: 8}], path(x / :x)
iex> p = path "hey" / 0
iex> 9 = view! %{"hey" => {9, -9}}, p

Creates composition of two paths which has some inspiration from logical or. This means that a ||| b path-closure tries to apply a and only if it returns :error, tries apply b

Example

iex> p1 = path :x / :y
iex> p2 = path :a / :b
iex> op = p1 ||| p2
iex> {:ok, 1} = view %{x: %{y: 1}, a: [b: 2]}, op
iex> {:ok, 2} = view %{x: 1, a: [b: 2]}, op
iex> {:ok, %{x: %{y: 2}, a: [b: 1]}} = set %{x: %{y: 1}, a: [b: 1]}, op, 2
iex> {:ok, %{x: %{y: 2}}} = force_set %{}, op, 2
iex> {:ok, %{x: %{}, a: [b: 1]}} = force_set %{x: %{y: 1}, a: [b: 1]}, op, 2

Creates composition of two paths similar to concatenating them together. This means that a ~> b path-closure applies a and only if it returns {:ok, something} it applies b to something

Example

iex> p1 = path :x / :y
iex> p2 = path :a / :b
iex> composed_path = p1 ~> p2
iex> {:ok, 1} = view %{x: [y: [a: [a: 0, b: 1]]]}, composed_path