expug v0.9.2 Expug.Compiler View Source

Compiles tokens into an AST.

How it works

Nodes are maps with a :type key. They are then filled up using a function with the same name as the type:

node = %{type: :document}
document({node, tokens})

This function returns another {node, tokens} tuple, where node is the updated node, and tokens are the rest of the tokens to parse.

The functions (document/1) here can do 1 of these things:

Spawn a child, say, %{type: :element}, then delegate to its function (eg, element()).
Simply return a {node, tokens} - no transformation here.

The functions indent() and statement() are a little different. It can give you an element, or a text node, or whatever.

Also see

Expug.Tokenizer is used to build the tokens used by this compiler.
Expug.Builder uses the AST made by this compiler.

Link to this section Summary

Functions

add_attribute(list, key, value)

add_child(node, child)

Adds a child to a Node

add_element(node, t, tokens, depth)

append_subindent(arg)

Consumes :subindent tokens and adds them to the value of node

attribute(arg)

Returns a list of [type: :attribute] items

compile(tokens, opts \\ [])

Compiles tokens. Returns {:ok, ast} on success

document(arg)

A document

element(arg, parent, depths)

Parses an element. Returns a %{type: :element} node

indent(arg, depths)

Indentation. Called with depth which is the current level its at

statement(arg, depths)

A statement after an :indent. Can consume these

subindent(arg)

Matches :subindent tokens and discards them. Used for line comments (-#)

subindent_capture(tokens, lines \\ [])

Link to this section Functions

add_attribute(list, key, value)

add_child(node, child)

Adds a child to a Node.

iex> Expug.Compiler.add_child(%{}, %{type: :a})
%{children: [%{type: :a}]}

iex> src = %{children: [%{type: :a}]}
...> Expug.Compiler.add_child(src, %{type: :b})
%{children: [%{type: :a}, %{type: :b}]}

add_element(node, t, tokens, depth)

append_subindent(arg)

Consumes :subindent tokens and adds them to the value of node.

attribute(arg)

Returns a list of [type: :attribute] items.

compile(tokens, opts \\ [])

Compiles tokens. Returns {:ok, ast} on success.

On failure, it returns {:error, [type: type, position: {line, col}]}.

document(arg)

A document.

element(arg, parent, depths)

Parses an element. Returns a %{type: :element} node.

indent(arg, depths)

Indentation. Called with depth which is the current level its at.

statement(arg, depths)

A statement after an :indent. Can consume these:

:element_name
:element_class
:element_id
[:attribute_open [...] :attribute_close]
[:buffered_text | :unescaped_text | :raw_text | :block_text]

subindent(arg)

Matches :subindent tokens and discards them. Used for line comments (-#).

subindent_capture(tokens, lines \\ [])