#LuaRock "htmlparser" Parse HTML text into a tree of elements with selectors [1]: http://wscherphof.github.com/lua-set/ [2]: http://api.jquery.com/category/selectors/ ##License MIT; see `./doc/LICENSE` ##Install Htmlparser is a listed [LuaRock](http://luarocks.org/repositories/rocks/). Install using [LuaRocks](http://www.luarocks.org/): `luarocks install htmlparser` ###Dependencies Htmlparser depends on [Lua 5.2](http://www.lua.org/download.html), and on the ["set"][1] LuaRock, which is installed along automatically. To be able to run the tests, [lunitx](https://github.com/dcurrie/lunit) also comes along as a LuaRock ##Usage Start off with ```lua require("luarocks.loader") local htmlparser = require("htmlparser") ``` Then, parse some html: ```lua local root = htmlparser.parse(htmlstring) ``` The input to parse may be the contents of a complete html document, or any valid html snippet, as long as all tags are correctly opened and closed. Now, find sepcific contained elements by selecting: ```lua local elements = root:select(selectorstring) ``` Or in shorthand: ```lua local elements = root(selectorstring) ``` This wil return a [Set][1] of elements, all of which are of the same type as the root element, and thus support selecting as well, if ever needed: ```lua for e in pairs(elements) do print(e.name) local subs = e(subselectorstring) for sub in pairs(subs) do print("", sub.name) end end ``` The root element is a container for the top level elements in the parsed text, i.e. the `` element in a parsed html document would be a child of the returned root element. ##Selectors Supported selectors are a subset of [jQuery's selectors][2]: - `"*"` all contained elements - `"element"` elements with the given tagname - `"#id"` elements with the given id attribute value - `".class"` elements with the given classname in the class attribute - `"[attribute]"` elements with an attribute of the given name - `"[attribute='value']"` equals: elements with the given value for the attribute with the given name - `"[attribute!='value']"` not equals: elements without an attribute of the given name, or with that attribute, but with a value that is different from the given value - `"[attribute|='value']"` prefix: attribute's value is given value, or starts with given value, followed by a hyphen (`-`) - `"[attribute*='value']"` contains: attribute's value contains given value - `"[attribute~='value']"` word: attribute's value is a space-separated token, where one of the tokens is the given value - `"[attribute^='value']"` starts with: attribute's value starts with given value - `"[attribute$='value']"` ends with: attribute's value ends with given value - `":not(selectorstring)"` elements not selected by given selector string - `"ancestor descendant"` elements selected by the `descendant` selector string, that are a descendant of any element selected by the `ancestor` selector string - `"parent > child"` elements selected by the `child` selector string, that are a child element of any element selected by the `parent` selector string Selectors can be combined; e.g. `".class:not([attribute]) element.class"` ###Limitations - Attribute values in selectors currently cannot contain any spaces, since space is interpreted as a delimiter between the `ancestor` and `descendant`, `parent` and `>`, or `>` and `child` parts of the selector - Consequently, for the `parent > child` relation, the spaces before and after the `>` are mandatory - Attribute values in selectors currently also cannot contain any of `#`, `.`, `[`, `]`, `:`, `(`, or `)` - `line1
line2

` is plainly `"line1
line2"` - All start and end tags should be explicitly specified in the text to be parsed; omitted tags (as [permitted](http://www.w3.org/TR/html5/syntax.html#optional-tags) by the the HTML spec) are NOT implied. Only the [void](http://www.w3.org/TR/html5/syntax.html#void-elements) elements naturally don't need (and mustn't have) an end tag - The HTML text is not validated in any way; tag and attribute names and the nesting of different tags is completely arbitrary. The only HTML-specific part of the parser is that it knows which tags are void elements ##Examples See `./doc/sample.lua` ##Tests See `./tst/init.lua` ##Element type All tree elements provide, apart from `:select` and `()`, the following accessors: ###Basic - `.name` the element's tagname - `.attributes` a table with keys and values for the element's attributes; `{}` if none - `.id` the value of the element's id attribute; `nil` if not present - `.classes` an array with the classes listed in element's class attribute; `{}` if none - `:getcontent()` the raw text between the opening and closing tags of the element; `""` if none - `.nodes` an array with the element's child elements, `{}` if none - `.parent` the elements that contains this element; `root.parent` is `nil` ###Other - `:gettext()` the raw text of the complete element, starting with `""` - `.level` how deep the element is in the tree; root level is `0` - `.root` the root element of the tree; `root.root` is `root` - `.deepernodes` a [Set][1] containing all elements in the tree beneath this element, including this element's `.nodes`; `{}` if none - `.deeperelements` a table with a key for each distinct tagname in `.deepernodes`, containing a [Set][1] of all deeper element nodes with that name; `{}` in none - `.deeperattributes` as `.deeperelements`, but keyed on attribute name - `.deeperids` as `.deeperelements`, but keyed on id value - `.deeperclasses` as `.deeperelements`, but keyed on class name