View Source Pathex (Pathex v2.4.0)
This module contains functions and macros to be used with Pathex and i
To use Pathex just insert to your context. You can import Pathex in module body or even in function body.
require Pathex
import Pathex, only: [path: 1, path: 2, "~>": 2, ...]Or you can use use
defmodule MyModule do
# `default_mod` option is optional
# when no mod is specified, `:naive` is selected
use Pathex, default_mod: :json
...
endThis will import all operatiors and path macro
Any macro here belongs to one of three categories:
Link to this section Summary
Types
Function which is passed to path-closure as second element in args tuple
This depends on the modifier
Value returned by non-bang path call
Also known as path-closure
Also known as path-closure
Functions
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}
Easy and convenient way to add pathex to your module.
This macro creates compositions of paths which work along with each other
Applies func under path in struct and returns result of this func.
Raises if path is not found.
Applies func under path in struct and returns result of this func.
The same as Pathex.~>/2 for those who do not like operators
Deletes value under path in struct or raises if value is not found.
Deletes value under path in struct.
Gets the value under path in struct or returns default value if not found.
Applies func under path of struct.
Applies func under path of struct.
Sets the value under path in struct.
Sets the value under path in struct.
Gets the value under path in struct or returns default when path is not present.
Inspect the given path-closure and returns string which corresponds to given path-closure
Applies the func to the item under path in struct and returns modified structure.
Works like Map.update!/3.
Applies func to the item under the path in struct
and returns modified structure. Works like Map.update!/3 but doesn't raise.
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.
This macro converts path (which can be matched upon) into pattern.
Gets value under path in struct and then deletes it.
Macro which gets value in the structure and deletes it.
Sets the value under path in struct. Think of it like Map.put/3.
Sets value under path in structure. Think of it like Map.put/3.
Gets the value under path in struct. Raises if path not found.
Gets the value under path in struct.
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
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
Link to this section Types
@type force_update_args(input, output) :: {input, inner_func(output), any()}
Function which is passed to path-closure as second element in args tuple
@type inspect_args() :: any()
@type mod() :: :map | :json | :naive
More about modifiers
This depends on the modifier
@type result(inner) :: {:ok, inner} | :error | :delete_me
Value returned by non-bang path call
@type t() :: t(pathex_compatible_structure(), any())
Also known as path-closure
@type t(input, output) :: (op_name(), force_update_args(input, output) | update_args(input, output) | inspect_args() -> result(output | input) | Macro.t())
Also known as path-closure
@type update_args(input, output) :: {input, inner_func(output)}
Link to this section Functions
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, 2Easy and convenient way to add pathex to your module.
You can specify modifier
use Pathex, default_mod: :jsonOr just use it with default :naive modifier
use PathexThis 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.
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})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})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_pathDeletes 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))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))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> [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 structureApplies 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"Sets the value under path in struct.
If the path does not exist it creates the path favouring maps when structure is unknown.
Example:
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, 1If the item in path doesn't have the right type, it raises.
Example:
iex> p = path "hey" / "you"
iex> force_set! %{"hey" => {1, 2}}, p, "value"
** (Pathex.Error) Type mismatch in structureNote that for paths created with Pathex.path/2 list and tuple indexes
which are out of bounds fill the empty space with nil.
Example:
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, 5This is also true for negative indexes (except -1 for lists which always prepends)
Example:
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, 0Sets the value under path in struct.
If the path does not exist it creates the path favouring maps when structure is unknown.
Example:
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, 1If the item in path doesn't have the right type, it returns :error.
Example:
iex> p = path "hey" / "you"
iex> :error = force_set %{"hey" => {1, 2}}, p, "value"Note that for paths created with Pathex.path/2 list and tuple indexes
which are out of bounds fill the empty space with nil.
Example:
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, 5This is also true for negative indexes (except -1 for lists which always prepends)
Example:
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, 0Gets the value under path in struct or returns default when path is not present.
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)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 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, incApplies 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, incNote: Exceptions from passed function left unhandled
iex> over(%{1 => "x"}, path(1), fn x -> x + 1 end)
** (ArithmeticError) bad argument in arithmetic expressionCreates 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, mypathPaths 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,:tupleand: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}], pThis macro converts path (which can be matched upon) into pattern.
These requirements must be satisfied in order for this macro to work correctly:
- Path must be inlined into this macro. This means that path must be defined in a argument of this macro
- Defined paths must contain constants only
- 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"}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))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))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, 123Sets 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, 123Gets 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}}, pGets 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}}, pCreates 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, 2Creates 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